The Stovebolt Site Forums The Shop Area Engine Shop driveline vibration?

Ok guys I have a 41 216 with 4 speed box and original TT and 4.11 rear end. I had the truck out on a 120 mile run yesterday. Ran well top gear almost all the way. Near home I had to shift down to 2nd. On accelerating in 2nd there is only a slight increase in vibration but once I've changed into 3rd and accelerate the vibration is very noticable. Feel it through the seat. Its not so bad in top until it gets to about 45mph and then it kicks in again. Ease off on the throttle and there is a significant reduction in the vibration. First thought is the Uni joint. I haven't worked on a TT driveline before anything to look out for? With the 4 speed does the crossmember have to be removed when sliding back the front of the TT housing?

Thanks guys

Bob

Bob, could be a few things. I presume you have had the wheels balanced so i won't dwell on that. If the bushing in the TT is worn it could the cause. I don't know if your 4 speed has a TT so this is a guess. I am about to change the bushings in my TT.
Bill

I had this problem FOR YEARS. My mechanic didn't believe me. I knew that the vibration came from the recently rebuilt trans. I finally I took my truck over there, jacked the back end up and removed the rear wheels. I started the truck up and ran through the gears with my mechanic underneath until the vibration began. He immediately saw that the output shaft bushing was bad causing the driveshaft to wobble.

Thanks Bill and Tab. I'll jack up the back end and see if I can pin point where the vibration is coming from before I start going crazy with the spanners. Thanks guys.

Bob

UPDATE,

Ok guys I finally decided that the problem seems to be from the front of the driveline. It has however raised a few more questions.

When I unbolted the bell housing at the front of the torque tube and slid it back I found that there was very little oil ( maybe only 50mls )I seem to remember that the housing needs to be filled with a half pint (300mls)of trans fluid when its put back together. Never had any problem with a high oil level in the diff. Just wondering that when the PO built this maybe he forgot to fill the housing?

Three of the four cap bolts on the u-joint front yoke were loose ( its just as well the lock tabs had been installed. There is a little bit of sideways movement between the trunnion and each of the four trunnion bearings with some discolouration on the trunnion shafts. How much play is acceptable?

There is also noticable play on the splined drive shaft. Could it be time to remove the bushing and instal an okie bushing?

Any other jobs that I should be looking to do while I've got the TT disconnected?

Sorry for all the questions guys but its the first time I've worked on a TT driveline. It's another in a growing list of jobs that I've done over the last few months that I wasn't expecting to have to do. This truck has supposed to have had a complete rebuild.

Anyway as always I'd appreciate your input.

All the best

Bob

Just bringing this up to the top again guys. As the 41 is a daily driver I'm pretty keen to get the old truck back on the road asap.

Cheers

Bob

I don't think you want the ball housing full of oil. When you get everything back together you should pour about a half cup thru the small hole at the end of the transmission. This will lubricate the u-joint until it starts to come in from the trans. Was the inside of the ball housing scored from the u-joint hitting it? If it is then either the u-joint is sloppy or the gap between the collar and the ball housing is too tight. The gap between the two is crucial and although I don't know how the 41 compares to my 49, I would think they are alike. In my shop manual there are directions for determining the gap, which is set up with carboard shims. It is too long to go into here but when I did mine I used 4 shim/gaskets between the two pieces. Too tight and it will bind the u-joint and too loose it will leak. With 4 I was okay and I have just pulled it apart again to install the okie bushing assembly. The idea behind having multiple shims is that if it starts to leak at the joint you can loosen off the bolts and tear out one of the shims.
If you are all apart I would suggest to err on the side of caution and change what you need to. A friendly transmission shop should tell you if your u-joint is good. And if nothing has been done to the bushings in the TT then an Okie kit would be a good idea. However do not believe all the ads about the Okie job being done in an hour. I finally got my front bushing out today and that alone took an hour.
Bill

Thanks Bill,

There was scoring inside the ball housing. There was also no shims in place. While this is off I'll replace anything that looks suss as you suggest.

Thanks again

Bob

There is also a possibility that you may have broken leaf springs in the rear, some are undetectable till ya take em apart leaf by leaf, this will also cause a vibration at about 45 to 50 mph............resto44

Bob, about the shims. The way I did it was to bolt the ball housing and collar to the rear of the trans without the u-joint in place. Start with one shim and tighten down the collar. The book specifies "that it should not be too loose or too tight". If it is too tight then add a shim and so on. You have to take the ball housing in one hand and try to move it with some effort. Too many shims and the ball housing will flop down which you do not want. It is time consuming but it works. The only problem I had was how tight was too tight or how loose was too loose! Too bad they could not specify a torque-type setting. What kept me going was the thought that these trucks were often repaired in the field (literally) and the people who did it were not rocket scientists.

Resto thanks for the info I'll keep it in mind and check that area as well.

Bill there is some slop on the trunnion. I've ordered a u-joint kit, shim kit and okie bushing. The bearing at the back of the gearbox seems fine. The front yoke bolt wasn't all that tight either ( certainly not to specs anyway ). I've started to practice my cursing and swearing so that I'll be up to scratch by the time the okie bushing arrives. Cheers mate

Bob