Sad front differential??

[Gdsmith07]

Well here we all are,

I wanted to pick the minds of some experts on my what I’m thinking is a front differential issue.

So I’ve rebuilt the entire front end on my Yukon since purchase. Steering,
suspension all brand new.

When engaging 4WD I get what feels like a big amount of drag. Every other vehicle I own is either 4WD or AWD solid Axel and IFS none of the others feel this way.

So not only do I have a dragging feeling when engaged in 4WD I’m getting a almost whir maybe you could call it a growl as I increase speed but only with 4WD engaged.

I also have a continuous *click or *tap that sounds very similar to a cv Axel. I initially
Thought maybe it was suspension angles, or alignment or steering issues and I was throwing axels out but I’ve since fixed/diagnosed all other related issues.

When I first got the the Yukon I drained and filled the front diff, and then I also check the level in the transfer case. t-case was fine on level. Front diff was low but it was to be expected. The PO had mentioned a front diff leak and hadn’t been using the 4WD except in emergencies as he had a fear of bombing the diff.

I replaced the front Axel seal reassembled everything and drained and filled the front diff.

Looking for some opinions maybe even some direction, I’m probably going to drain the front diff and see about metal shavings. Other than that I am not an expert in the field of differentials. I mean I’d give a rebuild a go …. But it’d be a first hahaha

 

[rockola1971]

Disconnect front driveshaft at front diff. Jack frontend off the ground and turn diff by the yoke. You'll feel it if the front diff is screwed up. You replaced the front diff pinion seal? How many miles ago was that? Use a new crush washer? Set lash correctly?

 

[swathdiver]

When you engage it, are you driving on pavement or concrete, a hard surface?

@Matthew Jeschke

 

[Gdsmith07]

I’ll give it a look,

I replaced the front drivers side Axel seal. I haven’t touched the pinion seal.

All I’ve done to the front diff was replace the drivers side axel seal where it had a leak and then drained the fluid and filled with new.

I get the *tap or *click in 2WD when 4WD not engaged. When 4WD is engaged I still have the *tap/*click and I get a whirring noise almost a growl which increases in loudness with speed. At low speeds, 10pm. And under, not Much noise except for the *tap/*click.

I’ve been doing lots of research into the 8.25 IFS differential. From what I can tell there’s a possibility I messed the bearings and or auto adjuster up when replacing the drivers side Axel seal. Maybe it’s a culprit, maybe the PO grenaded the front end and didn’t know it. But I’ve replaced the entire front end, the only things left would be from the differential to the T-Case but I don’t feel/hear anything from the T-case it all sounds front of the cab.

I also replaced all the U joints front to
Back when I did all the underside work.

I’ll give it a lift and see what i can find and get back.

 

[Gdsmith07]

When you engage it, are you driving on pavement or concrete, a hard surface?

@Matthew Jeschke

I’ve got the AUTO 4WD option I was under the assumption this was your engagement option for hard surfaces or rock.

But not on pavement no, loose rock yes auto 4WD, or 4H do roughly the same however when AUTO engages it’s an obvious *drag* to the vehicle. A very obvious drag like an almost
Lurch you forward kind of feeling. The only way I can explain it is almost a dragging or binding feeling. I haven’t done differential work I’ve swapped whole axels in and out but never built a differential. I understand the mechanics and workings. Which is why I keep coming back to something’s wrong in the differential.

My 03 silverado that I had never made such issues.

 

[swathdiver]

I think you have two problems, something is wrong internally and a CV Axle needs replacing. Probably less expensive to get one from a salvage yard. I had a boot go on one of my CV Axles and replaced the whole thing with a Cardone Reman which are rebuilt using GM cores.

 

[Gdsmith07]

I think you have two problems, something is wrong internally and a CV Axle needs replacing. Probably less expensive to get one from a salvage yard. I had a boot go on one of my CV Axles and replaced the whole thing with a Cardone Reman which are rebuilt using GM cores.

This is my second set of cv axels, second set of brand new Cv’s boots are completely fine. On first drive out of the garage had the same *tap/*click sounds almost exactly like a cv Axel, and it’s rhythmically speeds up and slows down with speed.

If you Jack the front end up and spin the axels they make no noise if you put the Jack under the LCA and Jack it up I get no noise. The only thing I haven’t done is Jack it up off all 4’s and turn it on put it in 4WD and look for Binding or noise.

I guess it’s 100% possible the cv Axel is bad again that I got 2 bad back to back cv’s.

But I’m now remembering an interesting thing the PO told me when I bought. He said he had thought he over tightened the Axel nut the cv Axel I can’t remember if he said the driver or passenger side and had thought he caused it to fail. But that was two brand new cv axels ago.

I feel like I’m going a little crazy hunting for this noise. I guess if it is a differential I could just see about it getting a new one geared differently and match the rear to it. Hahaha

 

[Gdsmith07]

But aside from that noise the 4WD engagement just doesn’t feel right. Too much drag and the weird noise.

 

[Erickk120]

But aside from that noise the 4WD engagement just doesn’t feel right. Too much drag and the weird noise.

Is the drag in any form of 4wd, or just 4hi/4lo? doubt the axles are bad, since you replaced them. If you assembled the engagement portion of the axle the same way it came out, it should be good, unless you just popped the axle and shoved it back in, you can do it on the driver side, but not the passenger side. How bad is the popping you are describing? Could be a chipped tooth in the ring gear, but you would have seen pieces when drained, so hard to tell. I would remove the front drive shaft and feel what the pinion feels like, if you can rotate it several times and its smooth and it doesn't make any weird popping noises I would try it with the shafts engaged and front raised. Pinion should will be harder to turn, but should feel smooth. As far as noise 4lo will always feel heavy and noisy as you go up in speed.

 

[Gdsmith07]

Is the drag in any form of 4wd, or just 4hi/4lo? doubt the axles are bad, since you replaced them. If you assembled the engagement portion of the axle the same way it came out, it should be good, unless you just popped the axle and shoved it back in, you can do it on the driver side, but not the passenger side. How bad is the popping you are describing? Could be a chipped tooth in the ring gear, but you would have seen pieces when drained, so hard to tell. I would remove the front drive shaft and feel what the pinion feels like, if you can rotate it several times and its smooth and it doesn't make any weird popping noises I would try it with the shafts engaged and front raised. Pinion should will be harder to turn, but should feel smooth. As far as noise 4lo will always feel heavy and noisy as you go up in speed.

I haven’t even engaged it into 4LO I’ve only ran it 4HI and AUTO. In fact while on a test drive my brother was riding shotgun and I made that comment on how I didn’t even know if it worked.

The dragging feel is strong enough I didn’t want to cause anymore damage by dropping the gearbox into LO.

I just popped the drivers side and slid it back in. I had seen that you can’t do it on the passenger side and lucky for me it was on the driver side. Just pulled it out, slide hammer, and was able to push it back in. Didn’t give any problem to it and haven’t had an Axel leak hahahahaa but o guess I could have screwed the bearing/adjuster.

It’s not very loud, I can’t feel
It in the steering wheel but can in the floorboard again kind of leading me to diff. Sound almost exactly like a cv joint going bad infact almost identical but not as loud as cv that’s gone bad if that makes sense? Same noise but quieter.

The only thing I’ve ever noticed that made me think hmm was the rotation of the drivers side front Axel does somewhat feel a little more “heavy” in the sense of more force required for movement. But not much. Just enough to go oh that’s different from the passenger side. But again it’s a differential I guess just a little can be a long way in these things. The more I write what I’ve noticed the more it making sense the differential is bad hahaha