Thump thump, G80 and confusing gear oil

[Tnman54]

I have 0.9mm ( a smidge greater than 1/32'') on passenger side, none on driver side. A new cross-pin and C clips didn't eradicate it.
Yours has more wear somewhere. Maybe a new cross-pin and C clips would eliminate it, maybe it is clutch wear. It doesn't strike me though as clutch wear at a level to cause concern. What is of concern (in case you are unfamiliar with it) is the axle play reaching a level where the C clips can drop out. That though requires movement the thickness of a C clip (circa 4-5mm).

thank you for that info, im new at differentials apparently. Ive got it on the stands now and when turning the axles i can tell theres something not right inside there. Im getting ready to pull the cover again but this time im going to look much harder. I was ignorant the first time by thinking the problem was just not enough oil. Im beginning to understand the system better thanks to some of you guys. There's a pretty good video on youtube, would be much better if the guy had the camera at a better angle...it is what it is.

 

[RichLo]

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[Tnman54]

since the mechanics i know are 2 wks or so booked up, I decided to give it another look. I dont see anything wrong, everything looks good. I dont suppose that a person can start the truck, put it in drive, and see whats going on with the diff cover, wheels, and drums off. I can spin it around, no broken parts or defective gears that I can see. I may just have to accept defeat and wait on someone who knows

 

[Schurkey]

I dont suppose that a person can start the truck, put it in drive, and see whats going on with the diff cover, wheels, and drums off.

You'd have nearly-zero lube on the moving parts.

'Course, you'd also have near-zero load on them. I think you could get by with that for thirty seconds, maybe more.

Problem is, everything will be moving too fast for you to see anything useful.



Wild Guess: Running the differential that low on lube toasted the clutches, and maybe the bearings. Why that causes binding only when driving forward, I don't know. I still wonder about the transmission.

 

[Tnman54]

You'd have nearly-zero lube on the moving parts.

'Course, you'd also have near-zero load on them. I think you could get by with that for thirty seconds, maybe more.

Problem is, everything will be moving too fast for you to see anything useful.



Wild Guess: Running the differential that low on lube toasted the clutches, and maybe the bearings. Why that causes binding only when driving forward, I don't know. I still wonder about the transmission.

You'd have nearly-zero lube on the moving parts.

'Course, you'd also have near-zero load on them. I think you could get by with that for thirty seconds, maybe more.

Problem is, everything will be moving too fast for you to see anything useful.



Wild Guess: Running the differential that low on lube toasted the clutches, and maybe the bearings. Why that causes binding only when driving forward, I don't know. I still wonder about the transmission.

The drivers side is not engaging, feels that is where the binding is...if I get in wet grass and give it the throttle, the right side wheel spins, never the left. I dont understand about the clutches or how they work. Could clutches bind on just one side?

 

[RichLo]

I just skimmed this thread again and I may have missed it but have you had your drivers side brake drum off yet? That really sounds like you may have had a shoe or both separate from the metal backing.

 

[Pinger]

thank you for that info, im new at differentials apparently.

My crash course in G80s was last year - trying to eradicate that 0.9mm of play on the passenger side wheel.

Ive got it on the stands now and when turning the axles i can tell theres something not right inside there. Im getting ready to pull the cover again but this time im going to look much harder. I was ignorant the first time by thinking the problem was just not enough oil. Im beginning to understand the system better thanks to some of you guys. There's a pretty good video on youtube, would be much better if the guy had the camera at a better angle...it is what it is.

While you are there check the cross pin just in case the wrong one has been fitted. I doubt that that's the problem but for the time it takes to check... If it protrudes (the end opposite the end with the bolt) it catches on the pinion - not the casing as I previously said.

The drivers side is not engaging, feels that is where the binding is...if I get in wet grass and give it the throttle, the right side wheel spins, never the left.

Something wrong there. That's exactly the scenario the G80 is designed for.

I dont understand about the clutches or how they work. Could clutches bind on just one side?

I'd have to have another delve into G80 operation to be certain but generally if one axle shaft gear is locked to the diff cage, the other one is compelled to follow the locked one's behaviour (as they are linked by the gears the cross pin carries).

I know you are detecting something not quite right within the diff but the suggestions of others that the problem could be elsewhere are valid. I'm struggling to figure how worn, sloppy clutches would cause it to bind and anything more mechanical in the diff would likely be clunky and noisy.
That it isn't locking up on wet grass points to something amiss though and does kinda imply the clutch engagement is awry - within the clutch pack rather than the mechanical part (bob weights)?

 

[Schurkey]

I dont understand about the clutches or how they work.

Review that video a few more times. I had to watch it four or five times before I "got it".

Could clutches bind on just one side?

I suppose, but it wouldn't matter. Unless both sides engage, the locking doesn't "work". If neither side engaged, one wheel would still spin just like an "open" differential. Difference in suspension loading/torque reaction, tire grip, brake drag could affect which wheel turns. It's usually the right side due to engine torque unloading the right side of the vehicle.

Yeah, that Gov-Lock is not working properly. But I don't know how that causes the binding you're describing.

 

[Tnman54]

something im now wondering about before I have drums turned is this piece of metal welded to the outside of the drum, im guessing to balance? I really havent given it much thought until now. Also, I noticed that I have a bit of side to side/ up and down play in wheel bearings

 

[Schurkey]

something im now wondering about before I have drums turned is this piece of metal welded to the outside of the drum, im guessing to balance?

Yup.

I noticed that I have a bit of side to side/ up and down play in wheel bearings

Sounds like they're "done".