My brother has an 04 LB7 2500 HD/crew. Bought it from a dealer around Aug 04. bought it in WA state and the truck came from Canada. Had around 8K miles on it when he bought it. I beleive he has had the front diff vibration/growling noise since he got the truck and I told him to take it in asap to have it looked at. But as brothers do, he put it off and in the interim installed a 6" lift and 35" tires. I warned him about fighting the dealer "afterwards" because of the lift/tire issues but that didn't do any good.

So now his truck sits at the dealer after he had the lift double-checked, alignment checked, etc. Everyone that has looked at the truck thus far says the lift is installed "perfectly" ...both the installer and 2 other shops.

The dealer drove/acknowledged the problem. Disassembled front diff and says they really can't find anything wrong other then uneven gear wear and possibly a bad bearing. They said it's his baby and a new front diff will cost around $2300.

I told him the front diff/growling problem was referenced on this forum in multiple threads ...think even Patrick said he's seen lots of trucks, specifically 04's with overtightened pinion beariigs that cause this problem. There is even a TSB specific to synthetic lube to be installed in trucks in cold weather climates (Alaska/Canada) ...the truck came from Canada.

At this point I'm just trying to collect info he can possibly use to convince the dealer the lift is not the source of the problem. The truck had the problem before the lift, the lift has only been on for about 400 miles and the truck is basically new still (12K miles).

I have collected several threads and the TSB for him to print out. Anyone have any tips? ):h I know he has an uphill battle at this point however I am fairly certain at this point based on the information I have found the problem is not a result of the lift and the dealer/GM should fix at their expense.

Can anyone run his VIN so I can get a listing of the work/TSB's that has been done on his truck? His truck is sitting at a Lebanon, Oregon dealer ...

What is his VIN? I have seen a few front diffs eat the pinion bearings on lifted trucks. The oil level needs to be adjusted after the lift is installed. I filled mine through the breather hole. Most of the HD lifts involve cutting the mounts off (which I'm sure you are familiar with) Then the diff is mounted so that the pinion points up more. This will cause the pinion bearings to be starved for lube if the fill height isn't adjusted properly. (This is why a dealer can blame it on the diff, even though we all know it was there before.) I agree that he should have addressed this sooner. It is awful hard for us to return a diff to GM with the mounts cut off. He should rebuild his. I have put all new bearings in these many times, without replacing the case or ring/pinion. Gear noises from a poor or used R/P setup typically start at 40 mph. Not really much of an issue in 4x4.

What is his VIN? I have seen a few front diffs eat the pinion bearings on lifted trucks. The oil level needs to be adjusted after the lift is installed. I filled mine through the breather hole. Most of the HD lifts involve cutting the mounts off (which I'm sure you are familiar with) Then the diff is mounted so that the pinion points up more. This will cause the pinion bearings to be starved for lube if the fill height isn't adjusted properly. (This is why a dealer can blame it on the diff, even though we all know it was there before.) I agree that he should have addressed this sooner. It is awful hard for us to return a diff to GM with the mounts cut off. He should rebuild his. I have put all new bearings in these many times, without replacing the case or ring/pinion. Gear noises from a poor or used R/P setup typically start at 40 mph. Not really much of an issue in 4x4.
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Keep in mind the lift has been installed for 500 miles ...it had the vibration/noise "before" the lift and my brother has personally never had it in 4WD except to test. We also drained/refilled all diffs right after he got the truck with Mobil synthetic as well as changed oil, etc.. I think the truck had right around 8K on it when he bought it and has around 12K on it now.

Also, he has the SuperLift that didn't require cutting any mounts like my Rancho lift did.

See, it's easy to focus on the lift as the cause :) when in fact the truck had the problem BEFORE the lift...but that isn't valid anymore because he can't proove it. However my brother has a lot of evidence on his side related to pinion/bearing problems. There are numerous threads where regarding overtightened pinion bearings on 2004 trucks. There is also the TSB related to cold weather climates that specifically states "This may contribute to premature pinion bearing wear if a vehicle is driven extensively in very low ambient temperatures.". My brothers truck is a Canadian truck. Perhaps the TSB wasn't performed on it which caused the pinion problem? These are the facts that contradict the lift as being the problem. In the end I guess he can take all this info and go up the ladder to GM and an attorney. Where that will put him I don't know.

would have saved alot of trouble if he would have got the noise fixed before the lift....

would have saved alot of trouble if he would have got the noise fixed before the lift....
God, I know. I would be having nightmares if it were my truck.

If he would be satisfied with a rebuild (all bearings, seals, crush sleeve, fluids), I think it is time for a road trip to Medford, I can take care of that, but a complete replacemant won't fly. We are under too much scrutiny from GM right now for high warranty dollars. What do you think?

Oh and to be clear, I do believe you that it was there before the lift. I was just trying to show the mindset of the typical dealer. I try to get everything covered, as my truck is lifted too, when it is my turn I don't want to foot the bill.

Max, to be clear on this, my front diff sits more foreward now, in the RCD bracket, when I was installing the mounting bracket a little fluid was lost when I took the bolts out, so I bought a quart of gear lube in anticipation of filling it back up once the lift was done. But after the installiation was complete I took the fill plug out to put some lube in, and oil immediately started draining out the hole due to the angle of the diff. I didnt try to put anymore in, it kind of bothered me because I knew I lost some lube on the ground but wasnt real sure about getting the right amount in. Maybe jacking the front end up so the fluid ran to the back of the diff would work? After reading this thread Im thinking I probably need to address this.

If he would be satisfied with a rebuild (all bearings, seals, crush sleeve, fluids), I think it is time for a road trip to Medford, I can take care of that, but a complete replacemant won't fly. We are under too much scrutiny from GM right now for high warranty dollars. What do you think?
I think your a saint :) Can you PM or email me your phone number so my brother can contact you? He has his own trucking company and currently on the road but he's getting ready to take off work and head to the dealer with the info I provided. I informed him of your offer and he thought it sounded great. His only concern is that the dealer where his truck sits now is probably going to try and make him pay to put the diff back together. Apparently they have the truck sitting outside with the diff in pieces inside the shop. Thoughts?

Use a 15/16" deep socket and remove the vent fitting to fill it through there. I add about 1/2 quart extra to trucks that have a lift that tilts the diff. The factory fill plug is now far too low since it is at the front of the diff. When I install lift kits I add the extra fluid on the bench. Be careful, it is easy to cross thread the vent fitting. Don't overtighten it or the o-ring will squirt out.

That synthetic fluid TSB has me very suspect that may be the culprit, coupled with the fact the upper a-arms have been replaced. Based on the condition of the under carriage when he bought the truck (very dirty) made me think the truck was used off-road a lot (4x4) ...probably a company rig or something up in Wadena, SK (Canada) where it is 2 degrees today. Assuming this is the case the diffs should have had synthetic fluid in them from day 1 ... or (quoting from the TSB) "This may contribute to premature pinion bearing wear if a vehicle is driven extensively in very low ambient temperatures."

http://www.quill-lakes.com/Wadena/local.htm

I have yet to see a Canadian truck that wasn't completely thrashed underneath. I don't think they have paved roads up there yet.):h

Mine is like new underneath. I very rarely drive off pavement. Up here farmers are usually the ones buying these trucks and they usually live on gravel roads. We definately don't have as much pavement as our US neighbors.

If you bought the truck from Saskatechewan you can bet that it was a farmer who owned it and it probably never saw a paved road. ):h