Whats the problem?

[destroyer1362]

I'm hoping its not the rear end but tell me what you think. When I take off from a stop in my truck it seems to buck a little like it's hesitating, but when I have it in 4x4 the bucking is gone. I've been in a truck with a u-joint on the way out and it doesn't feel like that. I also looked at the u-joints they look good and don't have any wiggle. If you all need more details just ask. I have a buddy that went to lincoln tech, how hard is it to rebuild a rear diff?

 

[grimm]

Are there any noises? Any chattering noises or any grinding sounds, etc? Is there gear oil leaking from any edges of the diff cover? If you suspect your rear end is going out, you can pull off the cover, and inspect the internals and the quality of the gear oil (e.g. are there any metal shavings/particles? is there not enough fluid? is there even wear on the ring gear? etc)

If you and your friend have some mechanical inclination, a service manual to go by, the right tools, and some patience, you could probably figure it out, but its not necessarily an easy task. If you are a little iffy about it, you might want to take it to a decent shop, or find a used/rebuilt axle at a good price and swap the whole thing out.

Also, if you rear axle is in need of attention, it could be the perfect opportunity to swap to the 6-lug 14 bolt semi-float 4x4 axle. Just a thought.

 

[destroyer1362]

When I'm coasting down hill in a parking lot and I tap the gas I can hear/feel a clank, other than that its completely silent. I can't tell if its coming from the u-joint or the diff. No oil leaking either. When I find the time I'll do a fluid change.
Is it possible to find a 14 bolt with a g80? Just for the sake of not having to install a locker.

 

[grimm]

Check your U-joints one more time to be sure. The "clank" you are hearing and feeling is the usual sign of worn out U-joints. I mean, U-joints are cheap and they are really not all that hard to replace if you have a bench vise and a typical socket set. They also have a tool specific for the job you can buy (or rent if you only need it once in a blue moon)

If you're completely sure those are fine, then inspect all components of your rear axle. You could have worn gears, bearings, races, etc. 14 bolt axles are pretty common, but most of the ones you see are 8 lug full floaters. Its hard to come across a 6 lug semi-float, and I'm sure even more-so difficult to find one with a factory locker. But they are out there; you just have to search around. They'll pop up on craigslist every now and then, sometimes for a pretty damn good price. So it might be worth looking into. They are tough as nails and definitely an upgrade that's worth the time spent searching. Its one of the things I plan on doing even though my axle seems to be in great shape.

 

[bowtiefreak]

Grease the slipyoke

 

[ScottyBoy]

Grease the slipyoke

THIS. I've heard of these same symptoms on many forums and 90% of the time greasing the slip yoke will solve the problem. But a lot of times, it will return again and you will have to grease it again. It kinda like the same problem with the Greasable steering shaft, it will be fine as long as it is packed with grease. Some people have been fine, some people have to re-grease thier slip yoke as often as every 6 months. I guess it depends on your driving conditions.

Here is a detailed write up on how to grease the slip yoke.

http://www.truckmodcentral.com/forums/showthread.php?t=2504&highlight=slip+yoke

 

[Danny_Z56]

Thanks for the link scott,i know what i'll be doing this weekend

Mine seems to be fine but still would not hurt to do this,esp with 139K on the clock.

 

[destroyer1362]

Yeah thanks for the link Scott.. I almost greased it 2k miles ago but was scared I was going to end up draining my whole t-case by pulling the shaft out. The torque spec for the u-joint retaining bolts is 15 ft/lbs right?