Lockup to non-lockup question(s)

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4spdragtop

4spdragtop

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Hi all, zero transmission knowledge here so I'm gonna ask a few transmission questions. Our 67 cuda currently has the orig 904 that would be non lockup. I bought a spare "built/rebuilt" 904 that is lockup.
What is required to use in our cuda? I believe the nonlockup came with a torque converter as I have one of those that has "CP112 lockup" written in marker on it.
Thanks
Steve

20240805_161809.jpg
 
I believe a 12vdc switched source to the single connector on the drivers side of the case to lock up the converter for better fuel mileage. I also believe the input shaft has a different spline found so converters are limited.
 
I put an RH42 (A500) in my Dart GT, and used the simplest controller - two switches. One activates the overdrive and the other activates the lock up. It was simple, easy and gives you lots of choices at higher speeds. Over time I have found that I don't even think about hitting the switches - you hear the rpms and just reach down and hit the button(s) without even really thinking about it. Until you get used to it, you'll probably roll to a stop without turning the lock-up off and kill the engine, but it's not a disaster.
 
You need a physically matching convertor.
The early models were fully hydraulic, and auto shifted into od as dictated by the VB.
>The later A999s electric-shift loc-ups, came with a deeper gearset, and
>IIRC the A998s came with either ratio.
Be sure to use the shift levers off your A904, or physically matching ones, as there were several different iterations.
> IDK about the power-handling of the factory loc-up.
>IIRC the A998/A999 had those identifiers cast on the BH.
 
str12-340 said:
I put an RH42 (A500) in my Dart GT, and used the simplest controller - two switches. One activates the overdrive and the other activates the lock up. It was simple, easy and gives you lots of choices at higher speeds. Over time I have found that I don't even think about hitting the switches - you hear the rpms and just reach down and hit the button(s) without even really thinking about it. Until you get used to it, you'll probably roll to a stop without turning the lock-up off and kill the engine, but it's not a disaster.
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I built a little fancier control on my 46RH conversion so it automatically unlocks the convertor & downshifts... But my understanding is the governor will still cause the trans to downshift from forth to second & when it goes into second it should unlock the convertor.... Is that not actually the case?
 
Thanks guys, as I mentioned zero transmission knowledge other than a pan drop and filter change lol, sooo do all lockup trans have OD?
 
4spdragtop said:
Thanks guys, as I mentioned zero transmission knowledge other than a pan drop and filter change lol, sooo do all lockup trans have OD?
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No, 999 and 998 are three speed transmissions with lock-up converters
 
1WildRT said:
I built a little fancier control on my 46RH conversion so it automatically unlocks the convertor & downshifts... But my understanding is the governor will still cause the trans to downshift from forth to second & when it goes into second it should unlock the convertor.... Is that not actually the case?
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It's not the case in an RH42 using simple switches. If I forget the lock-up it stalls the motor at idle.
4spdragtop said:
Thanks guys, as I mentioned zero transmission knowledge other than a pan drop and filter change lol, sooo do all lockup trans have OD?
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No - the 4speed OD automatics have a 4th gear housing that is where the simple tailhousing on a 904 or 727. They require serious surgery of the torsion bar/trans cross member loop and a much heavier trans crosmember, shorter driveshaft etc. ODs are easily recognized with a DEEP trans pan since the valve body hangs out of the bottom of the trans.

I just mentioned it because the OD manual switch part would be the same.
 
Can you give us the PK number stamped on the transmission pan rail ? It's on the left side just above the pan.
 
Thanks again folks.
Yep, I'll grab them tomorrow.
What would I need to change to use with my current sb and non lockup vert?
townsend said:
Can you give us the PK number stamped on the transmission pan rail ? It's on the left side just above the pan.
Click to expand...
 
Depending on the year of the tranny it just may be mechanical lock up. Just put the tranny in and go. Or buy a higher stall for it too.
 
4spdragtop said:
Thanks again folks.
Yep, I'll grab them tomorrow.
What would I need to change to use with my current sb and non lockup vert?
Click to expand...
Cannot easily be done, and certainly not worth it.
The whole front end has to be swapped over, and the VB, and not all VBs will swap over. I highly recommend just to obtain a correct convertor.

but the clutches and bands will swap over.
 
Here's #'s from it.
Sorry Kim not just gonna "drop it in". S**t always seems to go slower than the plan in my thick skull. I'm trying to "plan" an upgrade/swap. Don't wanna miss Moparfest again this year.
townsend said:
Can you give us the PK number stamped on the transmission pan rail ? It's on the left side just above the pan.
Click to expand...

oldkimmer said:
Depending on the year of the tranny it just may be mechanical lock up. Just put the tranny in and go. Or buy a higher stall for it too.
Click to expand...

20240807_171634.jpg
 
4130972 was used with 318 engine with lock-up , A904.
Date code 6453 would be March 29, 1979.
Front clutch has 5 disc.
Rear clutch has 4 disc.
5 disc front clutch are sometimes referred to as A999 transmission.
 
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You may not be able to use a LU trans in your car. The pilot register changed size between 1967 and 1968. 1967 and down had the smaller crank pocket. All lockup 904's had the converter with the large pilot, and it will not fit the crank. You cannot use the early converter in the LU trans. You need to measure the crank pocket to be sure. If you have the large crank pocket, just use the LU trans, and the LU converter. No other special parts are required, unless the LU trans is a much later trans (late '80's) that has a single wire switch connector at the rear of the main case, on the driver side (not the neutral safety/backup). Then the trans needs a switched 12 v signal to lock and unlock the converter.
 
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Charrlie_S said:
You may not be able to use a LU trans in your car. The pilot register changed size between 1967 and 1968. 1967 and down had the smaller crank pocket. All lockup 904's had the converter with the large pilot, and it will not fit the crank. You cannot use the early converter in the LU trans. You need to measure the crank pocket to be sure. If you have the large crank pocket, just use the LU trans, and the LU converter. No other special parts are required, unless the LU trans is a much later trans that has a single wire switch connector at the rear of the main case, on the driver side (not the neutral safety/backup). Then the trans needs a switched 12 v signal the lock and unlock the converter.
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He has a 340
 
Since we're on the subject of lock-up transmissions, this question seems appropriate.
Did any of the torque converter companies ever custom build a non lockup converter with the correct number of splines to fit a lockup 904 transmission.
 
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Thanks guys, remember we spoke a while back Charlie about the crank register? I got a piece made/machined to fit on my 67 converter to match the 70 340 crank.
Charrlie_S said:
You may not be able to use a LU trans in your car. The pilot register changed size between 1967 and 1968. 1967 and down had the smaller crank pocket. All lockup 904's had the converter with the large pilot, and it will not fit the crank. You cannot use the early converter in the LU trans. You need to measure the crank pocket to be sure. If you have the large crank pocket, just use the LU trans, and the LU converter. No other special parts are required, unless the LU trans is a much later trans (late '80's) that has a single wire switch connector at the rear of the main case, on the driver side (not the neutral safety/backup). Then the trans needs a switched 12 v signal to lock and unlock the converter.
Click to expand...
 
4spdragtop said:
Thanks guys, remember we spoke a while back Charlie about the crank register? I got a piece made/machined to fit on my 67 converter to match the 70 340 crank.
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At my age it is hard for me to remember who I spoke to about what. I forgot you had the later engine. I was just going by your initial post which just stated the year of the car. But maybe my post will help someone else.
 
4spdragtop said:
Thanks for the heads up @Charrlie_S you were right, tc snout approx 1.55" and crank is 1.80" depth of 0.64....holding pattern dammit.. :BangHead:
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Charrlie_S said:
At my age it is hard for me to remember who I spoke to about what. I forgot you had the later engine. I was just going by your initial post which just stated the year of the car. But maybe my post will help someone else.
Click to expand...
Your post is a help for sure! I quoted myself as well from a prev torque converter question I asked a while back.
 
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