truck pulling to one side

wayne36 · January 7, 2017

2004 silverado 2wd auto we had some snow recently and when driving in it if the rear wheels spin afterwards it feels like something is grabbing and the truck wants to pull to the right until I put it in reverse and back up for a short distance then its fine. Is this a brake caliber sticking or a gear problem?

rjgti · January 8, 2017

locker maybe

wayne36 · January 10, 2017

Thank you I was thinking it was more in the diff than a caliber.

wayne36 · January 22, 2017

Well had the diff checked and it was ok and had ABS mod checked and it was ok, all wheels turn freely no abnormal heat temps on the hubs. Now what?

Dnt · January 22, 2017

Truck new to you? The GM G80 locker rear end engages pretty roughly, a lot of people think their truck is broke if they have never heard it before and it engages. I like to drive with the traction control off and the back tires tend to spin easily. If they spin on wet pavement sometimes the G80 will sometimes engage, it pops snaps and jerks LOL and it does take a few hundred feet of driving to disengage. If you did not know what it was you would probably be trying to take it in for service.

wayne36 · January 22, 2017

I have had the truck for 7 years now and never had noticed it before and as far as I know I don't have traction control or at least one I can turn off. I haven't heard or felt a popping and it only does it turning right. This condition isn't like a alignment problem where the truck will slowly ease to the right this is like if you let got of the steering wheel it will pull you off the road imminently.

7milesout · December 11, 2018

Dredging this back up, for good reason. I'm in possession of my dad's truck while I do some light repair to it for him. He truck is a 2003 GMC Sierra 1500 4.8L 2WD SCSB.

I was driving it on wet pavement and stopped for a red traffic light. When it turned green I accelerated of course, and the rear tire(s) spun when they crossed the wet white stop line. Immediately after, its just like as described above. The truck wanted to drive through the woods! It pulled hard right. I had to steer at least 30° left to go straight. Letting go of the steering wheel would begin to induce a Davie Crocket exploration through the woods. From the rear, I would imagine the truck was dog-tracking … hard.

I pulled over, shut the truck off, and backed up a bit. When I started driving again, the truck acted as if nothing was up. Drove perfectly straight. My dad had told me about this before. This had to have been related to a) an anti-slip function in the rear diff, and b) electronic in nature. Or else it wouldn't have gone away based on shutting the truck off.

I am guessing that the pulling is because, whatever was going on, the left rear wheel was spinning faster than the right. Maybe the anti-spin feature activated the brake on the right rear? This was weird. My dad had told me about this phenomenon. I would love to put an end to this. My old man likes to sport around. He may not be around too much longer, so while he is, I say, let him burn the tires off it, if that's what he wants to do.

7milesout

7milesout · March 11, 2021

Wow, 2.5 years and no updates. Maybe there's a good reason. I'll explain that shortly.

Guys, my dad died 1 month ago. 2/11. Hard to believe it happened, and that it has already been a month. So anywho, his GMC truck as discussed above becomes mine. I have the truck at my house. It rides very poorly. So I went to get a front end alignment, just in case that was causing ride problems. They said that there really no sense doing the alignment since the tires are more or less worn out. And I agree. Towards the center, all 4 tires are very close to start touching the TWIs. They also said it needed shocks all around. Now that, I can believe too. As I type, the truck is in the shop to getting 4 new tires, 2 front shocks and an alignment.

Here's the kicker. As I was waiting for them to take the truck today, I got to looking at the sidewalls and noticed that 3 of the 4 tires are correctly sized at 255/70 R16. But the left rear was a 265/70 R16. This irked me to no end. As I'm betting whoever installed these for my dad had 3 tires that were needed and stuck this wrong sized one on there just to get his truck done and out of the shop versus waiting on the right size tire.

And then it dawned on me, what if? What if this odd sized tire being on the rear had something to do with the scenario as I described above (pulling and steering wheel 30° off after rear tire spin)? This slightly off size rear tire (larger on the left) would have caused the left rear tire / wheels / driveshaft to spin slower than the one on the right. Maybe this was a contributing or causing factor to the odd behavior as mentioned in the previous post. Maybe this only happened to my dad's truck (and maybe 1 other truck on the forums) due to mismatching tire sizes ... and that's the reason only me (and maybe one other guy) have experienced this odd event!

Here's my main question: Could this difference in driveshaft speed over the course of 40k or 50k miles have negatively affected the differential?

swathdiver · March 13, 2021

Yes, such a difference will put additional wear on the differential. The tire guys may have been malicious but were more likely careless and didn't check.

I 19 year old truck is likely going to need upper and lower control arms too by now, unless they were done before. Tires worn down in the center means they were over inflated.

7milesout · April 13, 2021

Thanks swathdiver - But, all else seems fine. Got the 4 new tires, front shocks, and it needed alignment. It drives much better now.

But I got to pondering the other day, and figured this whole thing out. The left rear was running the 265/70's, while all other tires were the correct 255/70's. So, what happens when the tires would spin over wet paint (as described in my posts above), this GM diff unit has a mechanical lock. I don't begin to fully understand it. But there's no electronics to it from my understanding. It locks mechanically when slip happens. I don't know what unlocks it. I pulled over and shut the engine off and that did the trick for me.

So, when it happened to my dad (and it happened to me once as well) and he would spin the tires over wet paint and the diff would lock, THE 265 TIRE has a longer rollout (larger diameter) than the 255 on the other side. This locking would induce the dog-tracking, and having to counter the dog-tracking by turning the steering wheel (as I remember) almost 90° to the left. Imagine rolling an ice-cream cone with the big side of the cone on the left. The cone will turn right. That is what my dad's truck did. When the diff locked, the larger diameter left rear wheel would cover more ground than the right side, steering the truck to the right. And the steering wheel would have to turn left to compensate.

So, he and I weren't making this up. But the fault was of the tire installer. And if I'm not mistaken, it was his local GM dealer that installed the tires. He told me at one point his truck was at the GM dealer shop for something (and I don't remember anything every going wrong, so likely it was for tires). The instant he drove away, it was dog tracking. He took it right back and when they drove it, it wasn't doing it any longer. I'm betting the dealership monkeys either pulled a fast one on him, or provided the typical quality work expected by OEM service ... crap.

7milesout · July 14, 2021

Just a follow up. Last night I installed new rear shocks. I didn't even have to jack up the truck. I drove the truck this morning and the rear shocks have made a considerable improvement. Before after going over bumps or even just typical road stuff (like transitioning to/from a bridge), the whole truck would shutter sometimes even the innards of the door(s) would rattle. It seems to be all gone now.

It still seems a bit rough in the front. I wish I had just done the front shocks myself. Oh well. The truck is quite good at this point. Everything works on the truck, including every bulb and nice cold A/C.