PK numbers

-
V

volaredon

Well-Known Member
Joined
Feb 28, 2010
Messages
3,673
Reaction score
2,078
Location
IL
Im trying to ID a trans I have, I know it is a slant 6 727.
is it a lockup or no? Id look at the input and know, but the trans is still in the truck.
where can I look up PK numbers for future reference?
here is the number from the trans in question;
PK4058384 8720 7883
what can be said from this number? how much info on internal guts can be determined from this number? Factory hi stall? or low stall able to be determined from PK?
how high is "hi-stall" and how low is "low stall?

Reason I am asking, is that when cranked, it is sounding like a bad tooth (or more) on ring gear. I haven't had inspection plate off yet but since I had another starter (or 3) laying around I swapped one of my spares in, and same noise. I have a new engine going together for this truck/ and if the ring gear looks like it sounds, once the engine is out, the TC is getting swapped. I have a TC in my sights for what seems like a good deal// but I need to know before someone else buys it, if my trans has L/U or not. if mine is L/U then the converter I am looking at will not work for me.

Runs and drives fine, drives like a non L/U. If it is supposed to be a L/U trans then that "feature" is currently inop.

1 more quick Q, something I don't remember ever seeing before. I had power washed the He11 out of this trans this past summer, while in the truck. Main case took to it well, could not get up onto tailshaft as well as I would have liked. less than 100 mi on truck since the douching of the engine and trans so its still clean.
I have not started the engine in about 3 months, and Im thinking this could be from converter draining back, and will be less of an issue when weather breaks and I am driving it more regular. Does this sound plausible?
The problem here, is that it appears that ATF may be seeping/leaking out threads of front band adjuster.
 
Dodge truck, 81, 6-225 A727, B,D1/2/350, long extension, 2wd.

Dodge Plymouth, 82-85,6-225,B/D1/2/350, long extension, lockup converter,2wd.

I think lockup should have electric connection on the case somewhere?
 
Last edited:
nope. not yet for the electric connection for lockup, that was still a few years off. All mechanical and controlled by a hydraulic valve, an "add on" small aux VB piggybacked onto the main VB "on topside". but I have yet to open this trans up for any reason, to see that. Thanks.
crap. it is a lockup. that means the converter I was considering buying won't work. there is a different spline count (by a total of 1 measly spline) between a non lockup and a lockup trans, on the input shaft. thanks for the info. does the list say what stall the converter would be that came within this trans (low or high stall)

OK next to that PK number were 2 additional groups of 4 numbers. After the PK4058384, that is followed by 8720 (space) 7883. any significance to that?
 
volaredon said:
nope. not yet for the electric connection for lockup, that was still a few years off. All mechanical and controlled by a hydraulic valve, an "add on" small aux VB piggybacked onto the main VB "on topside". but I have yet to open this trans up for any reason, to see that. Thanks.
crap. it is a lockup. that means the converter I was considering buying won't work. there is a different spline count (by a total of 1 measly spline) between a non lockup and a lockup trans, on the input shaft. thanks for the info. does the list say what stall the converter would be that came within this trans (low or high stall)

OK next to that PK number were 2 additional groups of 4 numbers. After the PK4058384, that is followed by 8720 (space) 7883. any significance to that?
Click to expand...
My chart doesn’t give any info on that, sorry. Would those numbers have anything to do with the 10,000 day calendar? Maybe someone else will chime in with info.
 
volaredon said:
Im trying to ID a trans I have, I know it is a slant 6 727.
is it a lockup or no? Id look at the input and know, but the trans is still in the truck.
where can I look up PK numbers for future reference?
here is the number from the trans in question;
PK4058384 8720 7883
what can be said from this number? how much info on internal guts can be determined from this number? Factory hi stall? or low stall able to be determined from PK?
how high is "hi-stall" and how low is "low stall?

Reason I am asking, is that when cranked, it is sounding like a bad tooth (or more) on ring gear. I haven't had inspection plate off yet but since I had another starter (or 3) laying around I swapped one of my spares in, and same noise. I have a new engine going together for this truck/ and if the ring gear looks like it sounds, once the engine is out, the TC is getting swapped. I have a TC in my sights for what seems like a good deal// but I need to know before someone else buys it, if my trans has L/U or not. if mine is L/U then the converter I am looking at will not work for me.

Runs and drives fine, drives like a non L/U. If it is supposed to be a L/U trans then that "feature" is currently inop.

1 more quick Q, something I don't remember ever seeing before. I had power washed the He11 out of this trans this past summer, while in the truck. Main case took to it well, could not get up onto tailshaft as well as I would have liked. less than 100 mi on truck since the douching of the engine and trans so its still clean.
I have not started the engine in about 3 months, and Im thinking this could be from converter draining back, and will be less of an issue when weather breaks and I am driving it more regular. Does this sound plausible?
The problem here, is that it appears that ATF may be seeping/leaking out threads of front band adjuster.
Click to expand...
If it's a lockup there are two converters used: Low stall (apprx. 2000) and the high stall(apprx. 2200) These converters fit both the 225 and the 318.

If it's a non lockup, the same stall rating, and again the converters were used on the 225 and the 318 engines.

If the converter you have "in your sights" is used, my advise is to avoid it. The problem with used converters is you don't know the condition of it inside. It may be perfect or a time bomb. I've worked in the industry and have seen converters that look like new, but when cut open, the story changes. I hope this helps.
 
No, I know of 2 b&m "tork master" converters that are brand new I was considering. One is here in our classifieds for a better price than I found the 1st one for. Not a lot of difference between low stall and hi stall then
the converter I was looking at won't work as it is for a non lockup trans , so the point is moot.
Unless I find a different trans, but there is nothing wrong with my current one except for possible ring gear damage.
I just figured if I can find a decent aftermarket one similar to what I mentioned here that would work for my unit, why not? I guess it's back to a rebuilder's special, as I ain't paying $600 for a converter. I have one for a 518 here that would actually work, now that I know that mine is a lockup version.
 
So any hope finding a decent converter for a 727 lockup that is more than just stock from a trans rebuilder?
 
volaredon said:
No, I know of 2 b&m "tork master" converters that are brand new I was considering. One is here in our classifieds for a better price than I found the 1st one for. Not a lot of difference between low stall and hi stall then
the converter I was looking at won't work as it is for a non lockup trans , so the point is moot.
Unless I find a different trans, but there is nothing wrong with my current one except for possible ring gear damage.
I just figured if I can find a decent aftermarket one similar to what I mentioned here that would work for my unit, why not? I guess it's back to a rebuilder's special, as I ain't paying $600 for a converter. I have one for a 518 here that would actually work, now that I know that mine is a lockup version.
Click to expand...
The A518 may or may not work. All 518 converters have a number stamped on the pump side(hub side)body of the converter. It will be 3 numbers, and these numbers are stamped by the factory. Examples: 875/595/642 and others. Get me the number and I can give you more information.
Do you really need a High Stall? You've made no mention of what engine and what has been done to it to need a high stall.
 
I've wondered, how high is high stall and how low is low stall..I've talked about this truck and what I want to do with the engine several places here in pretty good details
85 d150 long bed, building a forged crank slant 6 to replace the weak noodle original slant that is in there now. The truck came with the 727 and 3.21 which will both stay. Only reason I'm asking about converters is because listening to it start I think it has a bad ring gear. Otherwise I would have never brought up anything about whether I have a lock up or not, or anything about replacing the converter. I have swapped out starters to see if that may be the source of the noise with no change. As long as the engine is coming out that's the time to check it out and replace the converter if my fears turn out to be true. Will have a super 6, stock exhaust manifold hogged out to match the flange gasket, 2-1/4 all the way out. Oregon 819 reground cam, ported peanut head shaved for 8-1/2 to 9:1 ported and oversized valves. 3 season daily driver, want to be able to pull a 3000# popup with some camping gear in the bed. I am building towards stock for 85 360 hp numbers.
 
In about 1978, I put a 2800TC behind a fresh reman 225, into a 69 Barracuda; best thing I ever did for it.
That 2800 followed me from one Mopar to another, and eventually found it's way into my winter engine, a smog-era 318/4bbl; where it was again, a blast to drive.
One day my son made me an offer I couldn't refuse, and it (the 318/904/2800TC/3.23s), went into his 1984 D100, replacing the oil-burning lo-po 360 that was in it. My son drove it for many years, until he got married.He always loved that 2800.
Eventually he gifted that truck back to me, but the body was well,well, used.
 
Last edited:
volaredon said:
85 360 hp numbers.
Click to expand...
Do not confuse horsepower and torque.
You may be able to get circa 1985 360 horsepower out of your slanty, at some higher rpm. But you can never get 360 torque out of it unless you supercharge it.
And to tow 3000 pounds, with 3.21 gears, you are gonna need torque, cuz 65= about 2800rpm (10% slip) with 28"tall tires.
My guess is at 2800, it will take 150 footpounds..... or more. It's gonna take a lotta lotta throttle......
A loc-up will reduce your rpm to 2500, so Ima thinking; forget 150 ftlbs.....

Lemmee put it into perspective;
Suppose you get your 225 up to 140 hp at 4600rpm. that would be 160 ftpounds......... at 4600 rpm. How much will that be at 2800rpm?
IDK.
Enough to tow a 3000# pop-up , and propel nearly 4000pounds of truck, built lake a brick with a huge frontal cross-section. Why sure, but will it do 65mph?
IDK.
But even if it does, it might have to be floored.
 
Last edited:
AJ/FormS said:
Do not confuse horsepower and torque.
You may be able to get circa 1985 360 horsepower out of your slanty, at some higher rpm. But you can never get 360 torque out of it unless you supercharge it.
And to tow 3000 pounds, with 3.21 gears, you are gonna need torque, cuz 65= about 2800rpm (10% slip) with 28"tall tires.
My guess is at 2800, it will take 150 footpounds..... or more. It's gonna take a lotta lotta throttle......
Click to expand...
It would have to be a lot better once I get the new one built than the one in the truck now, and I'm thinking that if I had numerically higher gears that cruising I would be running even more revs.
And being an inline style engine like an old tractor with such a long stroke I'm thinking that torque should be plenty. It would have to pull better with less sense of "help me" (strain) than what I get out of the 3.9 v6 in my 99 dakota.
My 96 dakota (318 mag, 3.91s and OD) and my 01durango (360mag,3.55s, OD but nearly 275k miles) pull that camper like it isn't there.
I always hated how mopar castrated every 360 built with dished pistons. From almost day 1of originally creating the 360.
So now that you brought it up would you think that I should go low or hi stall?
 
volaredon said:
So now that you brought it up would you think that I should go low or hi stall?
Click to expand...
Because your rpm at 65 with 28s is 2500LU/2750 @10%slip, as for cruising, it makes no difference. In fact, for towing, you want the TC to be fully stalled and not slipping, so that it is not producing a bunch of heat.
But to get off the line half decently, the bigger your cam is, without a change in compression ratio, the more stall those 3.21s are gonna need. Without a Loc-up I would run at least a 2800 and a big trans cooler. With a loc-up, and a cam, at least a 3200, and the same big cooler.

But I gotta tell ya, you cannot compare a Magnum to a slanty, they are worlds apart. And your 3.687 slanty can never get on the same page with even the 3.9 never mind the 5.2. Your slanty pistons are just 3.400 inches in diameter, and the /6 only fires three chambers per revolution. It wouldn't matter if it had a 6" stroke, if the mixture is finished burning in the first three inches, and finished the big push in 3.3 inches, the rest of the time, the next piston in line and the ones after, have to drag it around until the next time it fires.
Here is a stock 5.2 dyno curve; Check out the torque at 2500, and at 2800. That's what you need to have so you can cruise at Part Throttle.
But check out the power associated with 2800, about 155hp.
Suppose the 5.2M cruises at 40% throttle or say 62hp. That leaves it 93hp in reserve for acceleration, for climbing, and for passing.
But if your 225, can only muster 75/80 hp at 2800, yur engine is nearly at WOT! With very little in reserve. And it's pushing about 32 sq ft of barn-door down the road, with no aero whatsoever.
Now, don't get me wrong, I have never had a slanty in my 84 D-100, and of that I am very glad. Cuz altho the worn out 360 could do 65, it took about 5 miles, I mean a really long time, to get up to speed. And forget passing.

power-318-gif.gif
 
volaredon said:
I always hated how mopar castrated every 360 built with dished pistons.
Click to expand...
By themselves the dish is not a bad thing.
It only becomes a problem when you swap out the factory cam, and swap in a 3/4 race cam and end up with no cylinder pressure for street driving, below 3000or so rpm.
But the cure is just a piston swap away. It's just that a lot of hotrodders seem to be too lazy to getRdone.
At the stock spec the 360 made about 137psi cranking pressure, at sealevel This is lots enough for what it was designed to do . But when you put a 340 cam into it, the pressure falls to about 123psi, so it gets pretty sucked out below 3000rpm, it still makes great power at 5000/5500.
The cure for the pressure loss is a higher stall for most guys, so the engine does not have to pull at sub-3000 rpms. But if you have a 4-speed, yur doomed. The proper cure is higher compression, usually pistons. By 8.8Scr the pressure is back to where it started ..... but why stop there? By 10/1 the pressure is up to 164psi, and now you got yourself a pretty Hot Rod.
But really, that cam is way to big for 3.21s, So lets sub in the next smaller cam and reduce the compression ratio for regular gas. The new magic number is 155psi at 9.4 Scr.
But guess what, at sub-3000rpm, the performance is only a lil better than the stocker was.
So like I said, by itself the dished pistons were not a bad thing; they did exactly what they were supposed to do.
But I like your use of the word castrated, altho in this instance, I think it's a lil harsh.
BTW; a V8 fires 4 chamber per revolution. So already, that is 25% more power pulses.
and a 225 has 37.45 cubic inces per piston, compared to 39.8 for the 318.
But in one revolution, the slant is sweeping 37.45 x3, versus the 318 sweeping 39.4x 4. So 112.35 compared to 159.2. That is almost 42% more to the 318. And that is why 318s have so much more torque; they are just able to move so much more air, at the same rpm.

Keep one thing in mind, that I earlier said;
If the mixture in the chamber is finished delivering it's push by 3.3 inches of stroke, the rest of the stroke is a net loss to the engine. The other pistons have to drag that piston around nearly 1.5 more revolutions, until it once again fires.
If a slanty was a steam engine, the 4.125 stroke would help it. But it ain't a steam engine.
The only time the long stroke helps the slanty is to make pressure on the compression stroke, with the abysmally low stock compression ratio, and with the factory cam. As soon as you change those, the advantage can rapidly become a hindrance.
 
my 318 Mag in my 96 Dakota cruises at 70, at not much more than 2000 RPM... OD, 3.91, 265/70R15 all terrains (its 4wd)
and you're saying that my doggy 3.9 is a better engine than the slant? I've had a couple other 3.9s, and even the '90 with the LA version seemed better than this one....
this one runs good, but it's a freakin DAWG getting up to speed, even with an empty bed and no camper on the ball....and more than 100K less miles of wear and tear than the 96.
I mean, it gets up to speed eventually... but to try and pass someone if I have to?? im talking someone going 10-under on a flat road and I punch it and move over into the other lane.... it takes FOREVER to creep up and gain any more speed so I can get outta the oncoming lane.... not much better when running empty. and if I have to pull even a slight hill with that 3.9? "HELP-ME".....
I'm not talking pulling that camper all the time with this truck.... maybe 3-4 times a year, having other vehicles that can do it helps.... but I like the 80s trucks so much better, for many reasons.... I work on newer (within 10-12 yo, mostly F150s at work daily as a fleet mechanic... I hate the newer trucks so badly) so I want the D150 to at least pull as good as my 96 318 Dakota.... definitely has to do better than the 99 with its wimpy 3.9 does, there's a huge difference between the 318 in the 96 and the 3.9 in the 99..... I've detailed my wants for this truck and this engine, and how I hope to get there, in more than a couple of threads elsewhere here at the forum......... trying to understand stall speed makes my head spin as bad as trying to wrap my head around specs in a cam catalog........
when I saw this D150 I have sitting in the PO's yard every time I drove by I thought sure it "had to" have a V8.... those trucks are slim pickens around me, in any condition. I was able to buy this one for a good price, and it is more solid than many 2011-2012 trucks that come onto my lift at work daily. so I got while the gettin was good.... I was surprised to discover a /6 and a 727, once I was able to make contact finally with the PO.
 
The 3.9M is just a 5.2M with two less cylinders. It again, has only 3 cylinders firing per revolution. But it has the same good heads that the 5.2 has. The same 3.91 bore, and the same 3.315 stroke. And AFAIK the same compression and cam specs.
So two otherwise identical trucks, one a 5.2M and the other a 3.9M. will instantly give you a fair comparison to show you exactly what the value is of those two missing cylinders. But the key here is "otherwise identical". You cannot compare a 3.91 geared 5.2 with a 2600stall TC, against a 3.9 with a 2200TC and 3.55s. Even tire diameters can,on a truck,make a huge difference.
Take your 5.2 and put the same rear gear and tires on it that are on your 3.9 equipped truck. Then disable two cylinders. Adjust the weights to match, stick your accelerometer on the windshield, and take her for a blast. Pound for pound, gear for gear, and stall for stall, the 5.2 less two cylinders should run pretty much the same as the 3.9.
But the Dakota/Durango has aero on their side; whereas the D100 is pug-nosed brick, that the faster you push it to go, it requires exponentially more power to push it thru the air. The math says everytime you double the speed, it takes double-double the power. So if the D-100 takes 35hp to go 40MPH, then theoretically it will take 140 to go 80, and 560 to go 160.
But maybe the Dakota only takes 25hp, because of the aero, to go 40, then 100 to go 80 and just 400 to go 160.
Now if you force the Dakota to run 3.21s with 28" tires, like the D-100 has, then in direct gear at 60mph, the rpm is 2310 @zero slip. So you got no accelerating capability left; the trans has to kick down into second. The Rs will rise to 3920 plus say 15/20% TC slip, so maybe 4500 on the tach. The engine is well beyond the torque peak, right on the power peak, getting set to slide down the back side. So really, you would get a lot of roaring, but not a lot of RapidTransit. And of course the stall is way back there at maybe 2200, so no help at all.
I know you really like the D-100,( I like my homely-D too) but if the 3.21s have to stay, then I would load it up and go for a test run, to see at what roadspeed, and under what conditions, the power really sucks. And I would do it with my accelerometer glued to the windshield, to remove my butt-dyno from the equation. My G-tek-Pro will also generate a horsepower curve and so I can very quickly analyze where in the roadspeed range, the power is tanking, and from those two, I can formulate a plan of attack. I got mine 20 years ago, when they were still cheap. But I gotta tell ya, whatever you gotta pay it's the best money you will ever spend, on account of you can spend your HotRod money on the most bang for the buck, where it will do the most good..
And I gotta remind you, that there are many things you can do to your slanty to make more power; but more power always comes at a higher rpm. And if the 3.21s gotta stay, then you will have a hard time to get to that higher rpm, in every gear except first, and you will never get to it in third gear.
For instance, with a power peak at 4800, with 3.21s and 28s, you will get there
in first gear at ~38 mph,
in second at ~72, and
in third at ~113.
So while you can build your slanty up in power, if that power is in a place you cannot get to, or where it does no good, then you are kindof pooched.
So shifting into Second at say 5100, the Rpm will drop to 3000, and now your engine has to labor up the powercurve again, beginning at 38mph. Of course it will be sucked out for a long time.......
Now say you had 3.91s,
then first gear would be revved out by 34mph, and by 38mph in second, the Rs will already have climbed to maybe 3200, so yur 200 rpm higher up the curve.
But, if the engine you built, sacrifices 20hp at 3200 rpm to get 30hp at 4800........... then the break even point in second gear might not come, I'm just guessing here, until 60mph with the 3.21s. So great, you got more power at 72 mph, but less from 38 to 60.
The point is this; you gotta analyze the whole combo, and not get stuck on high-rpm power.
If you need power at 38 to 60, you gotta build the whole combo to put it there. and castrating your 225 with 3.21s is not gonna help it one bit. If the 3.21s absolutely have to stay, like you keep saying, then upcamming the slanty, for more power at the top, is, IMO, the wrong thing to do. You would be way ahead to just supercharge it. That is the best way, IMO, for the 225 to get thru the 1-2 split of 1.45/2.45=.59
So once again, get yourself a G-tek or some type of accelerometer with graphing capabilities, and go generate some power curves. From those, you can figure out what to do next.
 
As for the Torque Convertor, It is kindof a magical device. It does two things, maybe three, depending on how you count,lol.
1) the TC provides a fluid coupling so you don't have to clutch it.
2) It is a Torque Multiplying device;
in that more torque comes out the back, than what actually goes in the front, and
3) it can be tuned to transmit the bulk of the engine torque at almost any rpm.

As for #2) most TCs have an finitely variable automatically adjusting multiplier between about 1.8 and 1.1. The multiplier is usually greatest at Zero mph, (not always) and diminishes with both rpm (torque input) and roadspeed (resistance to forward motion).
So lets say you had a TC that stalls at 2000rpm. That means, when you mash the gas at zero mph, the rpm will jump to ~2000rpm before the truck starts moving. If your Torque peak was at 2000rpm and say it was 70 ftlbs, then it is possible that the TC could multiply that 70 by say 1.6 so say 112 ftlbs.
But say you had a 2800, and that was also your torque peak. And say at 2800 your torque was 90ftlbs. That TC might have a multiplier now of 1.8, so 162 ftlbs leaving. That's an increase of 44.6%, just in the TC.......... Now remember, this is at zero mph.
Lets see what is happening at the tires.
Stock;
Your first gear ratio is 2.45 and your rear gear is 3.21, so into the rear axles, you are looking at :
With the 2000 TC and 3.21s
112 x2.45x3.21= 881 ftlbs
With the 2800 and 3.21s
162x2.45x3.21= 1274 ftlbs, a 44.6% increase
With the 2000TC and 3.91s
112x2.45x3.91= 1073 . See how that is ~22% better than the 3.21s, but is only half the percentage increase of what the 2800TC did. lets try
Both a 2800 and 3.91s I get
162x2.45x3.91= 1552, this is now 1552/881= 76% better than stock! ........ and we never even touched the engine! Remember, this is at zero mph. Remember,if the stall is at the torque-peak, then the multiplier will begin to diminish just as soon as the truck begins to move.
Finally; once the engine is past stall and continuously loaded (as in a dragrace) the multiplier will continuously diminish to it's minimum value, with minor blips along the way during gear changes. Therefore, after ~2800rpm, it no longer matters much what the less than 2800 stall, actually is.
Also bear in mind, I arbitrarily choose the torque numbers in these examples as a best guess; I just wanted you to see the magic that happens with the TC and gears.
 
good info, thanks. Ive had slant trucks before but they were all stick equipped/ IF the 727 were to go away then this one would be switched to a stick as well.
Ive done the swap a slant to a 318 thing before..... I thought in this case by not getting a V8 radiator, engine mounts, trans, etc I could put more into the engine itself.
Im not going crazy on a cam, but I am going up some from stock.
Im porting a head for it, I have a set of NOS valves I could put in sitting here, but I am going to go with the OS valves.
just an overbore of 20-thou-that's all the machinist said it would take to clean up.
going to a Super 6, I have an NOS BBD here for it already (not a Chinesium clone) all else being equal swapping to a super 6 "only" with no other mods, that in and of itself made a big difference in my son's '80 stepside with a slant. still not a barn burner but definitely noticeable improvement. Im hoping that mine will improve more than his did with teh additional work I have in mind for mine. Im not building a drag racer. That was never the plan. but I want to see what I can get out of a /6.
I have a 440 sitting here (low comp and low miles from a Winnebago) that I could stuff in there instead. I have 2 each 318 Magnums (in pieces) and 360 Magnums (also need rebuilt) that I have enough parts for to build one each, 318 and 360. But no good Magnum heads on hand. so I'll see what the slant will do this time.
If I dont like it then I can put that engine into my Volare (that I was gonna put one of teh 318 Magnums into) as it too was originally a slant that surprised me and actually ran pretty damn good for a slant car with 2.76 gears (once I replaced the plugged cats with straight pipe) so this engine wont go to waste. I sold that original slant from the Volare, this engine that I am working on now, is forged crank version.
 
You must log in or register to reply here.
-

Back
Top