Transmission Options?

-
JeremyAB95

JeremyAB95

Well-Known Member
Joined
Sep 21, 2016
Messages
118
Reaction score
29
Location
Ohio
I have a '70 Duster with a 318 small block in need of a transmission. The goal for this project is to produce a DD / weekend warrior setup, so I'm pretty set on an auto with at least five gears to keep cruising RPM down.

I've done plenty of research into the GearVendors Over/Under-Drive aux gearbox. I'd love to have one, but it costs almost as much as the car itself and I'd have to get my leaky old 904 rebuilt.

Any way to pair a late model 5-speed like the W5A580 (NAG1) or 545RFE to a small block and control it?

Any Ford or GM transmissions that would work? I saw a 6-speed valve body for the 4L80 (if I recall correctly). Don't know that I'd want to go this route because it'd make me happier to stay all Chrysler, but if I can spend less and get exceptional performance without using 100% Mopar I'll just get over it.

Bear in mind I'm still a college student and I don't have an exorbitant amount of cash to drop on a transmission or auxiliary gearbox. I'd like to try and keep it under $2000 at the most.

Any guidance or insight would be much appreciated.
 
not with out cutting up the floor, and or expensive adaptor kit, gm200r can be done still going to cost some money . best for budget, is a rebuilt a904.... and high gear 294 ish gears fuel mileage, and small carburetor... or cut it up and go wild but costs money...
 
An A500 from an early 90s Dakota will bolt to your engine and use the same shifter/throttle linkage stuff you have. You will have to cut out part of your torsion bar cross member to make room for the fatter rear end on this trans, fabricate a new cross member/trans mount piece, as well as shorten your driveshaft. No floor pan mods will be needed other than whatever you decide to do for reinforcement above or below the cross member area you cut out. This site has good information on this conversion. This is probably the cheapest way to overdrive your small block mopar.
 
Sedanman said:
Why go through all of that for a low performance 318?
Click to expand...

One step at a time maybe? :D
Some of us do it that way.
I got forced into doing it all at once because half way through putting my 5.9 together, my 904 trans started bitching.
A small mod to one of the converter bolt holes in the flex plate and it bolts right up as far as the motor end.
You will also need the larger driveshaft yoke of the A500, then you use the conversion U joint and just have your current driveshaft shortened.
The cooler lines are 3/8 instead of the 904's 5/16 and you will need the 80 inch speedo cable so it can reach the new length.
Speedo assembly on the A500 needs to be swapped from the electronic sensor to the gear type.
Then there's the decision on how to control OD and lockup (automatic or manually switched)

I did all the fab work, and I have somewhere around 500 into the entire swap, and that includes the stuff for fully automatic shifting.

A500OD.jpg


ShifterArt.jpg
 
Last edited:
A lock-up converter and a 200R4 is the closest I have ever come to an automatic 5 speed. If you build it yourself, use the US Cartool trans mount conversion, you will be close. Do a search on Mopar2ya and Treblig. They are both members here, and did a nice series of write-ups on the conversion. I spent more $ to do a heavy duty conversion in my '68. Best transmission I've ever driven with the exception of some of the modern Mercedes units.
 
2004R with 410 gears is the BOMB!! Plenty of zip off the line and great cruising ability. Some trimming of the upper cross member (no tunnel work) is required otherwise it's pretty straight forward.

Treblig
 
Treblig said:
2004R with 410 gears is the BOMB!! Plenty of zip off the line and great cruising ability. Some trimming of the upper cross member (no tunnel work) is required otherwise it's pretty straight forward.

Treblig
Click to expand...
You'd be the third to recommend the 200R4. In fact, the poster above you said you had a write-up. Is there any advantage to the 200R4 over the 700R4 or 4L60/4L80?
 
Sedanman said:
Why go through all of that for a low performance 318?
Click to expand...
You may have misread the title. I wasn't quite looking for somebody to bag on the 318, but if you do happen to have an extra 340 knocking around that you'd not mind parting with...
 
TrailBeast said:
One step at a time maybe? :D
Some of us do it that way.
I got forced into doing it all at once because half way through putting my 5.9 together, my 904 trans started bitching.
A small mod to one of the converter bolt holes in the flex plate and it bolts right up as far as the motor end.
You will also need the larger driveshaft yoke of the A500, then you use the conversion U joint and just have your current driveshaft shortened.
The cooler lines are 3/8 instead of the 904's 5/16 and you will need the 80 inch speedo cable so it can reach the new length.
Speedo assembly on the A500 needs to be swapped from the electronic sensor to the gear type.
Then there's the decision on how to control OD and lockup (automatic or manually switched)

I did all the fab work, and I have somewhere around 500 into the entire swap, and that includes the stuff for fully automatic shifting.

View attachment 1715012169

View attachment 1715012170
Click to expand...
Does it require a computer for the automatic O/D and lockup? Can the speedo pickup gear be scavenged from my 904 and used for with the A500 in lieu of the electronic sensor - or is it a unique part to the A500? Can I re-use my current starter as well?
 
JeremyAB95 said:
You'd be the third to recommend the 200R4. In fact, the poster above you said you had a write-up. Is there any advantage to the 200R4 over the 700R4 or 4L60/4L80?
Click to expand...
The 2004R is smaller so that way you have to cut a lot less. It's also lighter and doesn't suck as much HP (parasitic power loss). Here are the gear ratios, I think the 2004R has better ratios but it's up to you.

Tranny Ratios

If you build the 2004R with good HD parts (like in my 2004R thread) it should handle 400 horses. Remember, GM used the 2004R in the Grand National (fairly heavy car) and it held up just fine....smoking tires and ALL!!

I personally didn't want the hassle of an electronic transmission (4L60/80). I also used a non lock up converter so that I wouldn't have any wires, solenoids, or switches....just drive and have fun. So it depends on what you're looking for????

Treblig
 
Treblig said:
The 2004R is smaller so that way you have to cut a lot less. It's also lighter and doesn't suck as much HP (parasitic power loss). Here are the gear ratios, I think the 2004R has better ratios but it's up to you.

Tranny Ratios

If you build the 2004R with good HD parts (like in my 2004R thread) it should handle 400 horses. Remember, GM used the 2004R in the Grand National (fairly heavy car) and it held up just fine....smoking tires and ALL!!

I personally didn't want the hassle of an electronic transmission (4L60/80). I also used a non lock up converter so that I wouldn't have any wires, solenoids, or switches....just drive and have fun. So it depends on what you're looking for????

Treblig
Click to expand...
Thanks! I'll have to bookmark the site with that chart - that's some really useful info.
 
JeremyAB95 said:
Does it require a computer for the automatic O/D and lockup? Can the speedo pickup gear be scavenged from my 904 and used for with the A500 in lieu of the electronic sensor - or is it a unique part to the A500? Can I re-use my current starter as well?
Click to expand...

No computer needed, but they do make a nice little shift command box for it that lets you set the shifts where you want them, but I think it's a little pricey.
That's here, and it's good for the A500 as well as the 518 since they are the same control wise. COMPUSHIFT Mini for Chrysler A518/46RH and Chrysler A618/47RH
Myself I plumbed a steel line off the governor port and used adjustable pressure switches.
I have it set where OD comes on at about 50 and converter lockup around 70.
It's pretty easy to wire since all it needs to apply OD and lockup is 12v to either or both of the two trans terminals on the side of the trans so getting the plug with the trans is nice if it can be done.
This gives me 2,100 RPM's at 80 mph and right at 25mpg with a mild built 5.9 Magnum in the Dart with a 2.73 rear gear.
My car is a daily driver hiway car and not an in town racer, but the low ratio first gear of the A500 get's it off the line pretty quick anyway.

The speedo assembly off the 904 is perfect.
Current starter also works just fine.

You do have to egg one hole on the flex plate about 1/8 inch for the A500 converter, but other than that it all bolts right up.
And as mentioned already, all your existing linkage swaps over no problem.
 
I can usually turn on the OD at 35mph (but that's with 3.55 gears though).
When I'll swap the current 318 for a torque-built 360 soon, I'll probably install 3.23 gears back in the rearaxle.
 
TrailBeast said:
No computer needed, but they do make a nice little shift command box for it that lets you set the shifts where you want them, but I think it's a little pricey.
That's here, and it's good for the A500 as well as the 518 since they are the same control wise. COMPUSHIFT Mini for Chrysler A518/46RH and Chrysler A618/47RH
Myself I plumbed a steel line off the governor port and used adjustable pressure switches.
I have it set where OD comes on at about 50 and converter lockup around 70.
It's pretty easy to wire since all it needs to apply OD and lockup is 12v to either or both of the two trans terminals on the side of the trans so getting the plug with the trans is nice if it can be done.
This gives me 2,100 RPM's at 80 mph and right at 25mpg with a mild built 5.9 Magnum in the Dart with a 2.73 rear gear.
My car is a daily driver hiway car and not an in town racer, but the low ratio first gear of the A500 get's it off the line pretty quick anyway.

The speedo assembly off the 904 is perfect.
Current starter also works just fine.

You do have to egg one hole on the flex plate about 1/8 inch for the A500 converter, but other than that it all bolts right up.
And as mentioned already, all your existing linkage swaps over no problem.
Click to expand...

2K RPM doing 80 and 25mpg sounds good enough that you may have me sold on the A518 or A500, my friend. I will have to look into it further. Do you have your own write-up on the installation?
 
JeremyAB95 said:
2K RPM doing 80 and 25mpg sounds good enough that you may have me sold on the A518 or A500, my friend. I will have to look into it further. Do you have your own write-up on the installation?
Click to expand...

No writeup, because there are already enough of them out there.
 
Sedanman said:
Why go through all of that for a low performance 318?
Click to expand...
JeremyAB95 said:
You may have misread the title. I wasn't quite looking for somebody to bag on the 318, but if you do happen to have an extra 340 knocking around that you'd not mind parting with...
Click to expand...

I'll second that JeremyAB95! Not all of us have extra engines sitting around but just might have a good running mildly built 318 already in their car. Which is exactly my case too... I've got a 904 that will need rebuilding as well, If I ever go to a 360 or a 340 (when the opportunity arises) I'll still use the 904.
 
Trailbeast was a lot of help for me. Shout out......thanks man. Going in as soon as i can get to it.
 
Question because I do not know..Are the v6 trans and v8 trans the same trans in pickup trucks?
 
You must log in or register to reply here.
-

Back
Top