I'm hoping I can get some help/advise from anyone who knows transmissions. I have a 99 Supercab with the 4.6 V8. Thursday evening, I sprung a transmission leak, and found out that my tailshaft seal, the seal that the driveshaft yoke inserts, actually came loose from the tailshaft housing. I installed a new one on Friday, and it test drove okay. Anyhow today, (Sunday) the new seal came out again while driving on the freeway. When I got my truck home, I had my wife run the truck with the rear wheels off the ground so I could check the driveshaft. It was vibrating at the front where it inserts into the transmission. When I removed the driveshaft, I was able to wiggle the output shaft of the transmission, I'm assuming this is not normal. I'm going to call around some transmission shops tomorrow, but I was hoping someone could tell me what might cause this, so I could get some idea whether this is major or not.

Thanks to anyone who can help.

 

HI!... Make sure you check the slip-yoke it'self. Mine was slightly worn and it wore out the slip-yoke bushing, causing my tailstock to crack. Sounds to me like you might have a worn out slip-yoke bushing. Does the truck get a slight vibration when driving at high speeds?

 

Hi Gil,
Check this thread out for some more info on tail shaft tranny leaks:
https://www.f150online.com/forums/sh...highlight=leak

PS: I haven't had a day off yet with the new job yet to get down to Dego to pick up your springs yet. Not sure if you still have them or not. Perhaps this next weekend I might have a free day.

 

Neal and Area 52,

Thanks for your replies. I'm guessing the driveshaft angle because of the lift and an imbalanced shaft probably caused the problem. I will have a shop check for the worn slip yoke. As far as vibration, I wouldn't know, my worn mud terrains give me enough vibration, I probably can't notice it.

I have a couple more questions if you guys or anyone else can answer. First, the tailshaft should not wiggle right? And this slip yoke bushing, does it surround the slip yoke inside the housing? And lastly, as far as repair, can a shop perform this work while the tranny is still on the truck by simply removing the housing?

Thanks again.

Area 52,
I already sold the springs, but thanks anyway.

 

Actually, I did a search on slip yoke bushings and all my questions were answered. I'll be calling around tranny shops first thing in the morning.

 

Gil,
I didn't notice in your description on the amount of your lift. I would suspect the driveline angles are out of tolerance due to the lift which caused excessive wear/tear on the tail housing bushing and, possibly, the slip yoke.
And...I believe the tail shaft housing can be pulled without removing the entire tranny.

Glad you found out more info on your search...

Let us know what your final fix(es) is.

 

Thanks to the both of you! You guys led me in the correct direction. What I did this morning was call around so I could get a new slip yoke bushing and oil seal. The dealer said that the only way to get the bushing was to get the entire tail housing. I verified this by calling another dealer. Anyhow, I purchased the tail housing for 103.00 plus a gasket and it had a new bushing and oil seal already installed. It took me two hours to replace it. Due to the way the tailhousing sits, I had to remove the rear crossmember to get it out, but it went smoothly. I inspected the old housing and the bushing was toast. It was so worn that the grooves originally in the bushing were gone. If bushings exist in the aftermarket, I will have the old one replaced and keep the tail housing as a spare.

I dropped off my driveshaft to a drive shaft service place for an inspection and balance, and it should be ready as early as tomorrow afternoon. I just need to reinstall the driveshaft, top off my fluid, and road test.

Thanks again!

Gil

 

Gil,
Make sure the drive line angles are within tolerances or you might be facing the same problem again. I'd hate to see you spend the money for another new tailshaft housing. You might consult with a lift specialist regarding the driveshaft to axle/transmission angles.

 

I have a 98 4.6 5 speed. Their is a sleave around my tailshaft that is coming out and that is whats pushing my Tailshaft seal out! What Transmission do I have?