Silverado rear differential keeps failing

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#1

04 Silverado rear differential failed. Replaced it 3 years ago. It went out again. Replaced it again. Failed the next day.
Same symptoms as the first time.
Wet roads. Rear wheel drive. 1 wheel spins when turning at a light. That same wheel will hop during any left turn and i will have to hold steering wheel over to the left to keep driving straight. Turning right releases the wheel and i can drive normal.

This is the second repair shop that has been unable to determine why the rear differential failed. Any ideas? I can still drive perfectly fine when the roads are dry. The part is still under warranty but i dont want to replace it again just to have another part tear itself apart.


#2

Is it a Posi rear axle? Is the correct gear oil being used?

Thirdly, are these replacement differentials new or used?


#3

You can look at the RPO codes in the glove box to determine if the truck was equipped from the factory with a locker. There will be a white sticker in the glovebox with a listing of codes. G80 is the code for the locker. You’re supposed to use 75w90 gear oil with no additional additive.

Anyhoo, from the original description, it sounds like the locker isn’t releasing. I’m not sure why, and don’t have much advice other than taking it back to the shop that did the repairs. I’ve swapped entire axle assemblies a couple of times. I’ve never delved into the differential innards other than changing gear oil.

There’s really no reason that I know of why you’d be having repeat problems with a rear differential other than something inside isn’t being replaced or set up correctly when it’s being rebuilt. Good luck.


#4

That is one really weird symptom. My first guess is the same as Ok’s above, there’s a problem with the differential gear oil and additive spec (if required). Make sure the shop uses GM fluids next time. That they obtain from a dealership, and spec’s for your truck’s configuration. If not that then other ideas

  • something inside the diff adjusted improperly
  • some sort of problem with the axle shafts (wrong length, splines stripped, etc)
  • some sort of problem with the driveshaft, faulty u-joint, wrong length, wrong horizontal or sideways angle between the trans or transfer case and the rear diff, carrier bearing not adjusted properly, if two piece, the splines are not lubed properly, etc

Is there anything non-standard about this truck? Has it been raised or dropped? Bigger or smaller tires or wheels than it came with?


#5

Remembering I needed to buy anti slip additive or $30 a quart from dealer, may be cause the guy says no you only need x fluid, but you really need an additive or oem


#6

Was this a drum to drum swap with a used rear end, and are you using a lighter foot in the rain?


#7

It sounds like you have a broken leaf spring, the rear axle steering the truck and wheel hop are suspension problems.


#8

Wider tires than stock ones. The first time i did have the whole rear axel replaced with a used one. The truck ran fine for several years afterwards. This time the housing and assembly were replaced with a new one from gm


#9

I barely touch the gas in the rain. Its rear wheel drive so its way to easy to lose traction on wet roads


#10

Is it an e-locker? Just wondering if rain is causing a short in the wiring locking the the diff. I realize that is highly unlikely, but Murphy’s Law.


#11

10 1/2" ring gear semi floating or 11 1/2" ring gear full floating rear axle?

The 10 1/2" semi floating with limited slip was an OK axle assembly when running stock size tires, does not like wide tires, for some reason the differential can’t take the additional stress of the extra traction during turns, usually blows out the clutch packs and spider gears.


#12

GM installs an 8 5/8 inch ring gear, 10 bolt cover axle if it is a 1/2 ton truck. GM dropped the 8 7/8 inch 12 bolt semi-floater years ago. The 3/4 ton truck would have the Dana 60 which is a 9 3/4 inch full-floater- and it is almost indestructible behind a stock engine.

I’ve had problems with my 2004 Chevy 10 bolt rear as well. The first time it failed from a leak on a long trip so I didn’t see any puddles. It was rebuilt and failed 2000 miles later. I suspect the pinion bearing was over-tightened. That was replaced with a used axle that failed 500 miles later. I suspect a similar failure mode as I expect the mechanic over-tightened the pinion when installing a new seal. That axle was rebuilt and is just fine some 25K later.

Since the OP had a brand new axle installed, determining the reason for failure is nearly impossible.


#13

Its not an e-locker. I took it for a drive with the owner of the shop that replaced the rear differential and could not get just 1 wheel to spin on dry roads. Checked the springs. They appear to be in good condition. Its supposed to rain saturday so the mechanic who did the work will go for a ride with me on wet roads so i can make the diff lock up again. The part that i cant seem to understand is how it will stay locked while im going straight. It always fails making a left turn. I can make several left turns afterwards with it still locked. As soon as i make a right turn it releases.


#14

I have a 04 Silverado and it seems like the same thing. I’ll be in the rain and ill hit the gas or whatever to go sometimes too much and it’ll spin for 1/4 of a sec and thud thud thud and its locked, ill start making my turn after i let of the gas and it’ll hop and once I reach 30 miles an hour it disengages but it seems like when I turn left it will hop, I know that for sure because I take a left on the street leaving my work, but I’m not sure about right. Sometimes my differential don’t even lock.

I don’t get what you mean by “I will have to hold the steering wheel over to the left to keep driving straight”


#15

With this a recurring problem, apparently difficult for a shop to diagnosis, I’d probably just swap the two rear wider rear tires with the same size of tires it came with from the factory and do a drain/refill of the axle oil, making sure to include the correct amount and spec of additive per the owner’s or service manual. Then just monitor the situation. I’m guessing there’s a good chance that will solve it.

Beyond that, you already understand I presume that there’s only so much force the components in that area can take. If this is a work vehicle, and maybe you are a roofer, so you carry a lot of weight, that’s the reason for the wider tires, then earlier than normal failure may just be something you have to live with. The Ford 9 inch differential is the one the folks who build race cars seem to like, b/c it can handle pretty much any force thrown at it; if your truck is doing severe service, if this happens again ask you shop if it is possible to switch to that one.


#16

The differential is stuck so one wheel is pulling more. Thats why I have to hold the steering wheel over. If i didnt, my truck would make a right turn on its own. Just took it back to the shop. Its raining. I got the one wheel to spin but it didnt cause any problems. Tried about 10 times. Mechanic says that the oil/additive probably didnt get all the gears coated properly since they didnt lift the truck and let the wheels spin to break it in


#17

I don’t really understand the mechanic’s description of what went wrong. I read a service bulletin from GM (when replacing the fluid in my truck) that the GM 1/2 ton axles equipped with a locker don’t need any additive. I didn’t use any and didn’t have any problems. And gear oil would coat the gears pretty much as soon as the truck was driven, I would think. Hopefully they get you back on the road, though. Let us know what happens.