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C-4 output shaft twisted

Posted: Sun May 07, 2017 11:12 pm
by 1972ho
I have a problem with a small amount of trans fluid dripping from the rear seal so I decide to replace the seal,But when I pulled the driveshaft I found the yoke had some scoring so I bought a new one.Now after going through the process of replacing the new yoke on the driveshaft I try to install the driveshaft yoke back into the transmission now it will only go in only about an inch and tries to seize up to the transmission output shaft and even after a couple of attempts to install it,it will not go in but the old yoke will slide right in no problem.Does this sound like the the output shaft splines or twisted causing the new yoke not to go in are is it something else.

Re: C-4 output shaft twisted

Posted: Mon May 08, 2017 3:25 pm
by PackardV8
It is to be hoped your fitment difficulty is just normal wear-and-tear. Since most C4s are old now, the miles and years of drive/coast wear may have mated the old pair in a manner which shaped the output shaft splines differently than the blueprint. Then, drag launches exacerbate the situation. Flashlight inspection of the shaft and the old yoke should determine if there is any twist; because that usually occurs in front of the yoke.

Re: C-4 output shaft twisted

Posted: Mon May 08, 2017 3:52 pm
by 1972ho
From just looking at the yoke splines and the output shaft splines I can't tell if it is twisted or not.

Re: C-4 output shaft twisted

Posted: Wed May 10, 2017 11:18 am
by BirdMan
I have had that happen once, replaced the shaft and yoke, good to go then. After removing the output shaft you will find a small full length twisting and the yoke is soft enough to do likewise. Ticked me off having to redo trans but worked great afterwards. Maybe with a billet yoke to help with not twisting it will last a long time.

Re: C-4 output shaft twisted

Posted: Thu May 11, 2017 4:30 am
by crazyman
I can't recall whether it was a ford or gm, but I once had a similar problem. It turned out that the yoke and shaft had a "clock", where there was a tooth missing on both, and it would only fit one way. 20 years ago on probably 20 year old stuff at the time.... Check your output shaft for a missing unmachined spline.