TCase Trouble (1 Viewer)

[Goldbug]

I’ve got an issue that seems to be emanating from my transfer case. Started a free weeks ago and was most noticeable after driving a while and at higher speeds. When I’m coasting, I get a re-verb/vibration/wobble. Almost like a big rig engine brake da-da-da. Today it got much worse. It goes away if I’m pressing tha accelerator even a little.

The front driveshaft is looser than it should be. Rear is tight. I also recently re-did the motor mounts which may have moved the engine 1/2 inch or so in spots.

tonight I removed the front driveshaft and then started into the transfer case but stopped since I don’t know what I’m doing.

Any thoughts on likely culprits? This spline has a good bit of play in it. Hoping I can order something simple from Kurt at Cruiser Outfitters to replace rather than tearing the whole transfer case apart.

 

[pjohnson]

Vibration from the front driveshaft is only going to happen in 4wd.

What does the rear output look like?
Is the speedo housing tight?
Is it leaking back there?
How are your ujoints in the rear?

 

[Living in the Past]

Check the bearing on the rear diff pinion. The four speed sixteen spline are know to wear and make noise while coasting. But this shows more like a bearing.

 

[Goldbug]

Thanks guys, I guess I’ll start tearing into it to get to that bearing tonight.

@pjohnson, I agree that if I’m not in 4WD the loose front driveshaft shouldn’t matter. But the issue does seem to be clearly coming from the transfer case.

I’ll dig in a layer further and try to evaluate any bearings I find.

 

[1911]

How are your ujoints in the rear?

Pinion bearing and/or the u-joints would be my initial suspects.

 

[3_puppies]

did any oil come out when the flange was removed?
did you drain the oil in the transfer? how much?

 

[greenbeasty]

I would recheck everything I did with the mounts.
Then remove the front shaft and take it for a spin.
Reinstall front, remove rear, and drive again.
That should give you some good data.

 

[Goldbug]

did any oil come out when the flange was removed?
did you drain the oil in the transfer? how much?

No, didn’t drain the oil and no oil came out when I removed the front driveshaft.

 

[Goldbug]

I would recheck everything I did with the mounts.
Then remove the front shaft and take it for a spin.
Reinstall front, remove rear, and drive again.
That should give you some good data.

Ok, so drive it as is without the front driveshaft? Was thinking that too but worried I’d permanently damage something somehow but I’ll give that a shot. Good idea on checking everything with the mounts.

 

[3_puppies]

I wouldn't drive it anywhere until I made sure there is oil in it. I'd probably drain what is in there, see how much comes out, and if there are any large metal bits.
I wouldn't drive it with out the flange installed.
the mounts should have no bearing on the transfer case as the entire unit, engine, trans and transfer are a single unit

if the seal leaks between the transfer and trans all the oil from the transfer will migrate into the trans, leaving the transfer low on oil

 

[greenbeasty]

I wouldn't drive it anywhere until I made sure there is oil in it. I'd probably drain what is in there, see how much comes out, and if there are any large metal bits.
I wouldn't drive it with out the flange installed.
the mounts should have no bearing on the transfer case as the entire unit, engine, trans and transfer are a single unit

if the seal leaks between the transfer and trans all the oil from the transfer will migrate into the trans, leaving the transfer low on oil

That’s a great point!! Checking the oil would definitely come first.

 

[Goldbug]

So I drained the oil and it looked decent. Then @vfrer helped me pull off the front and rear output shafts and the bearings are definitely in rough shape. Ordered a rebuild kit from @cruiseroutfit and gonna do a lot of cleaning in the meantime. 43 years of gunk!

 

[vfrer]

The front output bearing is completely shot and has probably 1/8" play in it. Rear output also has play so removed the speedo housing and did find one thin shim. Everything looked ok otherwise. New front bearings and some shims on the back should tighten things up and then see if anything else is going on. Input gears all looked good.