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Fresh rebuild, 998, no motion!
https://slantsix.org/forum/viewtopic.php?t=28883		 Page 1 of 1
Author:  sixaddict [ Sun May 11, 2008 8:04 pm ]
Post subject:  Fresh rebuild, 998, no motion!
Hi all, local mechanic (30+ yrs. exp., very good) rebuilt his first Mopar tranny (mine), a 998, it's back in the car and it'll "drive & shift" on the lift but on the ground it'll only do reverse; no forward.

Here's what I know - tranny was pulled because converter (lockup converted to non-lockup status) disintegrated. Dissassembled, all parts checked & cleaned, replaced clutches & bands; previously modified but unknown kit/procedure; he installed a trans-go kit, everything checks out like the diagrams. A reconditioned lockup converter was installed. Lines cleaned, cooler cleaned.

This guy can rebuild 700R4s in his sleep... this should've been easy. He did mention there's "some vacuum thing with a spring in here that's the goofiest thing I've ever seen, but it went back in like it came out." :shock:

That's everything I know. Any ideas? Heck, any 998s? :(

Thanks in advance,
Scott in TX
Author:  SlantSixDan [ Sun May 11, 2008 9:21 pm ]
Post subject: 
There's nothing vacuum-operated in a 998...:shock:
Author:  sixaddict [ Sun May 11, 2008 9:35 pm ]
Post subject: 
Well that's not very encouraging now, is it? I wonder what he meant by that... he was stammering at that point, so it could've been "diaphragm" or "big plume" or "see you in June"... I may have misheard.
:oops:


But something about a spring mechanism.


BTW Isn't the lockup vacuum controlled?

Thanks! ~Scott in TX
Author:  SlantSixDan [ Sun May 11, 2008 10:18 pm ]
Post subject: 
Lockup's hydromechanical or electric, depending on production year and application. Never vacuum.

There are many spring mechanisms in the valve body...
Author:  ceej [ Sun May 11, 2008 10:25 pm ]
Post subject: 
Front Solenoid.
Do the Air checks in the FSM.

CJ
Author:  sixaddict [ Sun May 11, 2008 10:38 pm ]
Post subject: 
Application currently is a 78 Magnum, 318. Actual year of tranny unknown. Nothing electrical in there, though, from what I was told.

Thanks,
Scott
Author:  Slant Cecil [ Mon May 12, 2008 12:22 pm ]
Post subject: 
Sounds like the direct (rear) clutch isn't working or maybe has too much clutch pack clearance. The direct clutch is needed on all 3 forward gears but not for reverse.

Could be a valve body problem, direct clutch piston failure, bad/broken sealing rings, low fluid and/or hyd pressure, overrunning (sprag) not holding, and a few other things.

The 'hyd thing with a spring' sounds like the accumulator spring and piston. Leave it in.

The FSM is your freind, the ATSG 727/904 book is your second best pal.
Author:  sixaddict [ Tue May 13, 2008 12:55 pm ]
Post subject: 
Nine hundred and ninety eight thank yous, that's definitely a start. My guess is it's something simple that wouldn't necessarily grab his "Cheveyes"...

Scott
Author:  sixaddict [ Tue May 20, 2008 7:53 am ]
Post subject: 
He pulled it again, checked & doublechecked, all appears ok, all tests perfect when air tested. He thinks it's a valve body issue...

the tranny had been gone into and modified previously, unknown hands, unknown kit if there was one... when my mechanic put in the shift kit, he said it looked like half of what they said to do had been done, so he did the rest except for one ball that said something about manual control, continued on pg. 8. Well there was no page 8. So that stayed in.

We have the FSM for the car. Very good & helpful, but "mah car's still broke." :shock:

His next step: pull the valve body and trace the fluid path, maybe a tiny piece of my converter got lodged in there. QUESTION: will a valve body from a 904 bolt into a 998? If he needs a stock valve body to start over with I have an old 904.

Thanks again for the help!
~Scott
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