driveshaft play (1 Viewer)

[nhall80]

My 80 started making a typical driveshaft u-joint noise on the front shaft. I noticed the front u-joint had some play and mimicked the sound i was hearing when I moved it with my hand. After changing the joint, I've noticed the sound is still there. Not constantly and not as bad as it was, but definitely still there and in the same general area.

I also noticed the front driveshaft has a fair amount of play. Not loose bearing play like side to side, but I mean that I can manually turn the shaft quite a bit by hand. The rear shaft can't be moved by hand...and no other car I've had will allow me to manually move a driveshaft this much. I'm assuming I have an issue with either the front diff or the transfer case. Or is there some weird thing where the front shaft is supposed to move like this?

Anyone dealt with this? Where would you start to look for the problem? I'm not afraid of a front axle rebuild, but I just don't want to start chasing problems.

By the way, I rolled over 300,000 miles just a couple weeks ago, and the axles have never had a rebuild. Other than changing and topping off diff oil, they've got the full mileage on them. Same for transfer case.

Thoughts on where I should start to diagnose?

Thx.

 

[-Spike-]

Both driveshafts have some play, your rear one is the outlier. It probably had some tension on it. Chock the wheels, put it in neutral, and you will likely get the same play in it.

 

[hammerheadfistpunch]

My 80 started making a typical driveshaft u-joint noise on the front shaft. I noticed the front u-joint had some play and mimicked the sound i was hearing when I moved it with my hand. After changing the joint, I've noticed the sound is still there. Not constantly and not as bad as it was, but definitely still there and in the same general area.

I also noticed the front driveshaft has a fair amount of play. Not loose bearing play like side to side, but I mean that I can manually turn the shaft quite a bit by hand. The rear shaft can't be moved by hand...and no other car I've had will allow me to manually move a driveshaft this much. I'm assuming I have an issue with either the front diff or the transfer case. Or is there some weird thing where the front shaft is supposed to move like this?

Anyone dealt with this? Where would you start to look for the problem? I'm not afraid of a front axle rebuild, but I just don't want to start chasing problems.

By the way, I rolled over 300,000 miles just a couple weeks ago, and the axles have never had a rebuild. Other than changing and topping off diff oil, they've got the full mileage on them. Same for transfer case.

Thoughts on where I should start to diagnose?

Thx.

The slip joint on these trucks is notorious for slop, is the entire shaft spinning or just half of it? What happens if you load up the slip joint with grease? does the noise go away for a little while?

 

[Fj80oregon]

This is very common with 80 series. Did you replace both front DS u joints? When you did the front did you clean and grease the shaft and splines?

 

[CrabCake]

Similar thoughts here...I had some clunking in mine and greased both front and rear shaft splines, which took the noise away for about 1000 city miles...it's slowly coming back, so now I need to grease just the front or rear alone to isolate which one is getting sloppy so I can replace the whole shaft in question.

 

[BILT4ME]

The rotational play is an addition of tolerances. The front has more connections (6) than the rear (3).

Check pinion play
Drive flanges
Wheel bearings
Birfields
Axle shafts
DS yoke

If the front axle has never been rebuilt in 300k miles, it's time.

Plan on new drive flanges, axles, birfields, bearings, seals.

You should be getting under 1/4 turn of play at the DS/pinion when trying to rotate by hand.

 

[nhall80]

Thanks for the comments guys. I replaced all u-joints with MOOG 15k miles ago. So I only replaced the front joint that was loose. I did grease the slip joints after reading your comments and it seems to quiet the noise for just a few miles.

If it’s normal to have some play (1/4 inch or so), then I’m fine there. U-joints are not expensive and easy to change so I may go ahead and swap them all.

I have no play in the slip joints, but I wonder how to check the tolerances. When is it time to get a new ds?