Lock up torque converter.

[Cornpatch MO]

1968 Plymouth Satellite, 318 two barrel with 904 transmission. I am thinking about putting a lock up torque converter in it. Can iit be done without changing the transmission? Will it fit and work as it is supposed to? How would it be different than a stock one? Driveability? advantages or dis- advantages? Thanks for your input..........................MO

 

[OKDart]

I'm a novice as far as transmissions go, but I had one built for my big block. What I do know is the input shaft and valve body are different (also different spline count on input shaft/torque converter), not sure what else.
The torque converter is only locked above 35 MPH in 3rd gear. That's all I got on the subject.

 

[493 Mike]

Hi Mo,
If you are after mileage I think you would be further ahead to adapt FI to your car. I don't think the cost would be much different to do than the lock up conversion but, the drivability would be far more satisfying.
Mike

 

[Darter6]

Check with Hughes Transmissions. I believe they have a mechanical locking converter for the 904.
It was a few years ago I read a article on such a animal.

 

[Cornpatch MO]

Hi Mo,
If you are after mileage I think you would be further ahead to adapt FI to your car. I don't think the cost would be much different to do than the lock up conversion but, the drivability would be far more satisfying.
Mike

Having never driven a Mopar with lockup, I don't know what to expect. How much " slippage "do I now have with the stock converter? I may have to take the transmission out to fix some leaks, and thought that would be a good time to change converters. Better gas mileage would be a plus, but it would take a lot of miles to pay for FI ! . Although we did go on a 650 mile road trip a couple weeks ago. I got the Ply SS pretty much finished, but you know I won't be able to leave it alone !................MO

 

[OKDart]

Here's a pic showing the difference of the input shafts

 

[toolmanmike]

Just to be clear, you can't just "add" a lock-up converter to your 904 unless the transmission was made for it.

 

[wyrmrider]

get a lock up core and swap parts
or you can buy the necessary parts
if i was doing a rebuild I'd do it

 

[1 Wild R/T]

Considering how many complaints we would get at the dealership from owners of new cars with lock up convertors & how many had the lock up disabled to "fix" the complaint...

With the original hydraulic control they would lock & unlock constantly when traveling at the critical lock up speed....


When the control of the lock up is improved they can work great, modern cars are able to set the lock up, add a delay so it doesn't unlock if the speed dips 1-2 mph and actually set the unlock 5-7 mph lower than the lock up...

 

[Cornpatch MO]

Just to be clear, you can't just "add" a lock-up converter to your 904 unless the transmission was made for it.

Well, that pretty much answers my questions. I had no idea how they worked together......Thanks......................MO

 

[Cornpatch MO]

get a lock up core and swap parts
or you can buy the necessary parts
if i was doing a rebuild I'd do it

Since I am going to take it to a trans. shop to fix the leaks, and they will probably take it out, I may just see about putting in the lockup converter and trans. set up that is correct for it. That way I get a whole new set-up. Guess I will check that out.. Thanks all......................MO

 

[Cornpatch MO]

Considering how many complaints we would get at the dealership from owners of new cars with lock up convertors & how many had the lock up disabled to "fix" the complaint...

With the original hydraulic control they would lock & unlock constantly when traveling at the critical lock up speed....


When the control of the lock up is improved they can work great, modern cars are able to set the lock up, add a delay so it doesn't unlock if the speed dips 1-2 mph and actually set the unlock 5-7 mph lower than the lock up...

Great info......Thanks...................................MO

 

[Dipstick]

Lockup wasn't available before '78 so if you go looking for a complete transmission for a conversion, look for a '80 or later A999 with lockup. Much improved internals.

 

[wyrmrider]

right- or a cop car the whole a-999 trans is worth it
more clutches, double wrap band etc etc
my daughter kept loosing reverse in her PACER backing up long driveway cold
A999 from 360 AMC cop car and Transgo stage 2 kit fixed
ATF +4