Torque convertor question

[Valiant72]

My buddy changed out the tranny in his 1918 Dodge Brothers bucket this weekend. He got a rebuilt 904 from a guy who retired and closed his shop. He got a new TC and when he went to install it the splines aren't the same. So could the trans be a 998 with the lock-up or maybe just the wrong TC? How do you tell if it's a 904? Can the number of splines on the output shaft tell you? What's the disadvanage to the lock-up convertor? Thanks

 

[AdamR]

Count the splines. I believe the earlier 904s had a different spline count.

 

[C130 Chief]

Hmmm, I didn't think the 904 was available until 1920.

 

[Valiant72]

That one made be laugh. Thanks Chief. You know those Dodge boys were always ahead of their time.

 

[fishy68]

Adam's right. There is 2 different spline counts. I believe the early ones were 18 spline and the later ones were 27 spline. If it's a lockup it will have 26 splines and the front 1/2" or so of the input shaft will be machined down. The non-lockups have no machined part and splines all the way to the end of the input shaft.

 

[Valiant72]

Thanks everyone. It's a 998 alright. I read they had trouble with the early ones. People would shim the solenoid to eliminate the lock-up and it would be okay. Does anyone know when they started using this trans? I've got a 360/904 out of a 79 Newport but now I'm wondering if it's a 904 or a 998.

 

[SGBARRACUDA]

Thanks everyone. It's a 998 alright. I read they had trouble with the early ones. People would shim the solenoid to eliminate the lock-up and it would be okay. Does anyone know when they started using this trans? I've got a 360/904 out of a 79 Newport but now I'm wondering if it's a 904 or a 998.

I think the lock up went into service in 1978.

 

[340mopar]

I pulled a 360 4 barrel and 904 out of a '75 Cordoba parts car and it was a lock up. Can't confirm if it was the original though.


Chuck

 

[Dusterb318]

All you need to do is swap the input shaft with one from a non-lock up unit and you'll be fine to use the A-999 lock-up trans.....infact the lcok up trans had stronger planetray gears and are beefire on the internals and have an extra front clutch disc.

 

[DJVCUDA]

the pumps need to be changed as well... i just went thru swapping an 85 904 to non lockup... needed an input shaft , a pump, and had to keep the 85 valve body, they are different at the accumulator points going into the case.

 

[Dusterb318]

Ahh...I guess my swap was easier then...I had a 904 and I just swapped the input shaft off the gear and installed all the 999 guts.

 

[DJVCUDA]

the pump had 3 holes... one for lockup... i had to eliminate that.

also the OD of the shaft was different... not by much but different...

 

[C130 Chief]

Didn't the lockup 904's also have the lower gearset? Some earlier V-8 904's have the 5 disk front drum too. My 72 318 Dart did.

 

[Dusterb318]

Not all of them.....the one I pirated parts from was a 2.54 first gear.

 

[340mopar]

Somewere around the mid 80's is were the 2.74 gear showed up.


Chuck