2002 Trailblazer - G80 Skip on slow left turn

[fixnux]

It's only happened 3 maybe 4 times and it's only on left turns during extremely mild acceleration. The road way isn't slick so there shouldn't be any slip (and again super slow acceleration.) Seems to stay locked for a very short time. There is slight jerking and then it just stops 5-10 seconds later and all is fine.

I'm thinking I'll have the rear diff oil changed but was wondering if it's a precursor for a more serious repair and what suggestions others have.

That said, when there is slip it's functions properly and quickly. Also the above issues only seem to happen when it's >-10F. The truck has 217k miles. Most of that is high as the previous owners averaged between 19-27k per year. I'm uncertain whether there was ever any repairs. Whether it's the original diff ect. There wasn't a dealer report beyond regular maintenance and most that was before 100k.

Thanks in advance for any replies.

 

[The_Roadie]

Your profile isn't sharing if you're 4WD, but I have to assume you can tell if it's the rear binding up or the front.

When was the last time the diff oil was changed? If never, when when was the last time the level was checked? If never in 217K miles, I gotta ask what the condition of all the other fluids and things you need to change at 100K and 200K? (And 50K if 4WD).

That said, if you're asking about diff oil, just do it. Carefully examine the nature and the amount of what gets drained. Under 2 quarts, be worried. THAT will be the first clue you get about if you need to look in junkyards or car-parts.com for a replacement axle.

The G80 requires 100 RPM difference between left and right axles to lock up. It should be symmetrical, but its clutch packs are on the left side. A left turn could throw what oil is in there to the right, causing grabby clutches to engage with less than normal incentive. The usual latch-up triggering mechanism is pivoting pawls, but if the fluid is old or low, all bets are off. Something might be welded or broken by now even.

 

[fixnux]

Your profile isn't sharing if you're 4WD, but I have to assume you can tell if it's the rear binding up or the front.

When was the last time the diff oil was changed? If never, when when was the last time the level was checked? If never in 217K miles, I gotta ask what the condition of all the other fluids and things you need to change at 100K and 200K? (And 50K if 4WD).

That said, if you're asking about diff oil, just do it. Carefully examine the nature and the amount of what gets drained. Under 2 quarts, be worried. THAT will be the first clue you get about if you need to look in junkyards or car-parts.com for a replacement axle.

The G80 requires 100 RPM difference between left and right axles to lock up. It should be symmetrical, but its clutch packs are on the left side. A left turn could throw what oil is in there to the right, causing grabby clutches to engage with less than normal incentive. The usual latch-up triggering mechanism is pivoting pawls, but if the fluid is old or low, all bets are off. Something might be welded or broken by now even.

It is 4wd but it's the rear and not the front. I haven't even used the 4wd since around December. As mentioned, the 1st owner did all the maint but I don't know about the 2nd as there wasn't no record from the dealer. At least until 120k it was getting serviced regularly. After that I don't know.

It will be going to the shop @ 3PM so hopefully changing fluid will rear positive results.

Thanks for the info.

 

[gmcman]

Mine did that, exactly the way you described yours. Was on slight hill, wheels turned just a little to the left, thought I spun momentarily then it did it again another day. I pulled the rear cover to find a few chipped spider gears.

About $4-500 from the dealer so I went with a SS axle instead. If yours are chipped they can be replaced.

My thread.
http://gmtnation.com/f79/rear-diff-problems-4797/

 

[fixnux]

No chipped gears or at least nothing noticable when the cover was off.

Almost exactly 2qts but it was a bit black.

A bit less drive noise after changing the fluid. It also seemed to drive a bit
smoother.

Hopefully it holds up for another year.

Thanks everyone for the help on this.