Tearing It Back Down

jeremymike2 · March 12, 2011

I recently installed a 4.10 gear, it was bad a.. but I recently pulled my differential cover off to check backlash. Come to find out the whine and another noise i have been getting like a grinding noise in a few revolutions of the rear end, was a few cracked teeth on my pinion. Dont know why but im sending the set back to yukon to see if it could be caused by metal integrity or my fault. In a way i think im screwed, but what are yalls thoughts. What would cause the teeth on the pinion to crack, i know it was chipped on the edge. I have had the differntial in for 2 months now. Reason why i checked was that grind sound at 20 to 30 kinda pissed me off. Pinion was set properly i had correct gear pattern, weird.

Stevens03 · March 12, 2011

That sucks... Hopefully you figure it out. Keep us posted.

jeremymike2 · March 12, 2011

Oh believe me i will, yeah it does suck, but i hope they can help me out. If not im going to be eating 300 dollars and thats never good. Especially when you get hooked on the take off it really gave my truck.

700 sportsman · March 12, 2011

I take it you installed it yourself? I really doubt they'll give you a new set, especially if your set-up was off.

jeremymike2 · March 14, 2011

I take it you installed it yourself? I really doubt they'll give you a new set, especially if your set-up was off.

After taking it back apart, i realized the bearing that goes behind the oil seal on the pinion. I can basically pull the bearing through the front of the differential. No, i did not install it myself. The place where i got the pinion from said i did not have to replace any bearings since the truck has 50,000 miles on it, well of course except for the pinion bearing. Its weird how that bearing on the front of the housing moves around. Im

assuming and only assuming, that when it went out, under load it moved and caused the teeth to chip then crack. I guess we shall see what they say. Its supposed to be there by friday. Oh yeah, quick edit, ha ha, before i took everything out i check the work and everything was on, i mean dead on. So i know it wasnt installation error by the mechanic, or maybe it is, but i know for sure the bearing failed.

GPSilverado · March 15, 2011

I take it you installed it yourself? I really doubt they'll give you a new set, especially if your set-up was off.

After taking it back apart, i realized the bearing that goes behind the oil seal on the pinion. I can basically pull the bearing through the front of the differential. No, i did not install it myself. The place where i got the pinion from said i did not have to replace any bearings since the truck has 50,000 miles on it, well of course except for the pinion bearing. Its weird how that bearing on the front of the housing moves around. Im

assuming and only assuming, that when it went out, under load it moved and caused the teeth to chip then crack. I guess we shall see what they say. Its supposed to be there by friday. Oh yeah, quick edit, ha ha, before i took everything out i check the work and everything was on, i mean dead on. So i know it wasnt installation error by the mechanic, or maybe it is, but i know for sure the bearing failed.

That sucks. I swapped my 3.42 for a 4.10 about 10 days ago. I replaced both pinion bearings on mine though. What may have happened to yours is that the pinion nut was overtightened when you were checking pinion depth (assuming that you checked it without the crush sleeve until you got it where it needed to be), or that you had too much pinion bearing preload when finished.

It makes sense though that the failed pinion bearing could cause the pinion gear failure, especially with the 0.003 - 0.006 backlash specs. That is tight.

I just thought of another issue that might have caused this... Did you break in the gearset properly? It is VERY important to do the break in according to their instructions. (I also went with the Yukon gearset)

EDIT: Another thought. If you used a new crush sleeve (surely you did) but failed to crush it to the proper setting, i.e. too loose, then the freeplay in the pinion moving forward under load leaves the front bearing loose, which lets the drive shaft vibrate the bearing inside the bearing race, which would eat the bearing fairly quickly, and also low fluid in the differential would effect the front pinion bearing before any other bearing probably.

jeremymike2 · March 25, 2011

Well they replaced the ring and pinion under warranty, hell yeah. I'm trying to look up the pinion bearing for timken or any other. The Ac delco number is S1371 and part number is 15286375. I just hate going to the dealership and spending another 90.00 dollars on a bearing i can get slightly cheaper. Also would anyone know what the crush sleeve part number be?