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904 transmission slips when cold

Posted By: dodgefreak

904 transmission slips when cold - 07/16/14 07:37 PM

Our recently rebuilt 904 in my brother's '76 Cordoba slips in 1st gear until it completely warms up.
Any suggestions where to start?
Posted By: BigBlockMopar

Re: 904 transmission slips when cold - 07/16/14 10:19 PM

- Fluid checked in Neutral?
- Kickdown linkage hooked up and adjusted properly?
Posted By: dodgefreak

Re: 904 transmission slips when cold - 07/17/14 02:46 AM

Quote:

- Fluid checked in Neutral?
- Kickdown linkage hooked up and adjusted properly?




Yes and yes.
Works fine when you pull it down into low and also when in reverse.
Line pressure maybe? Or valve body issue?
Posted By: RapidRobert

Re: 904 transmission slips when cold - 07/17/14 02:54 AM

I was hoping that Kunkel would chime in. I ain't sure which band affects which gears but I would adj the band on the outside (KD I believe) & if that did not do it then pull the pan & adj that band. I had trouble getting to 72 inch lbs then backing off the # of turns so per Kunkels advice I went with 1/4 and 5/16 lever to piston clearance (I forgot which was which I'd have to check my notes). Next step would be to pull the VB and air check the ports for clutch/servo function.
Posted By: 383man

Re: 904 transmission slips when cold - 07/17/14 04:16 AM

Actually when you take off in drive there are no bands applied. In drive first the rear clutch is applied and the rear sprag (overrunning clutch) holds. When you put it in manual low the low/reverse band applies so you have eng braking in low gear when the shifter is pulled in low. In drive low there is no eng braking as the sprag is basically a mechanical one way clutch. But putting it in manual low all you do is apply the low/reverse band. But I have not ever seen a sprag slip when cold as when you put it in manual low you are just overriding the sprag and holding with the band. I would think you have worn seals in the rear clutch but cant see why putting it in manual low would help you if you did have seal problems. Ron
Posted By: dodgefreak

Re: 904 transmission slips when cold - 07/17/14 08:38 AM

Quote:

Actually when you take off in drive there are no bands applied. In drive first the rear clutch is applied and the rear sprag (overrunning clutch) holds. When you put it in manual low the low/reverse band applies so you have eng braking in low gear when the shifter is pulled in low. In drive low there is no eng braking as the sprag is basically a mechanical one way clutch. But putting it in manual low all you do is apply the low/reverse band. But I have not ever seen a sprag slip when cold as when you put it in manual low you are just overriding the sprag and holding with the band. I would think you have worn seals in the rear clutch but cant see why putting it in manual low would help you if you did have seal problems. Ron




Fresh rebuild with all new seals. Maybe 200 miles on the trans.
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