4x4 shakes

georgshe · February 19, 2007

there's a 94 z71 sierra i'm looking to buy, and all drives fine when it's not in 4 wheel drive, but when i test drove it, it drove fine for a minute in 4H, but after switching out and into 4L, the whole truck shakes...and then after trying to change back into 4H, it still shakes...then when i change back into just drive it was fine again...the steering was fine, well, the wheel itself didn't shake, just the truck. i'm still willing buy it and get it fixed since it seems like only the 4x4 is affected, but i'd like to get an idea of what might be causing it and about how much it would cost to fix it...

ericrlong · February 19, 2007

there's a 94 z71 sierra i'm looking to buy, and all drives fine when it's not in 4 wheel drive, but when i test drove it, it drove fine for a minute in 4H, but after switching out and into 4L, the whole truck shakes...and then after trying to change back into 4H, it still shakes...then when i change back into just drive it was fine again...the steering was fine, well, the wheel itself didn't shake, just the truck. i'm still willing buy it and get it fixed since it seems like only the 4x4 is affected, but i'd like to get an idea of what might be causing it and about how much it would cost to fix it...

I assume this was not done on dry surface!!

yeehaw87 · February 19, 2007

As long as your not going lock to lock, it is very unlikely that you will break anything, especially with stock tires. The only concern would be if CV joints were shot, then they might break. But if they were shot, they need replacing anyway.

ewood01 · February 19, 2007

It is possible the front driveline needs new ujoints.

95Sierra2500 · February 20, 2007

It is possible the front driveline needs new ujoints.

No u-joints in the front driveline aside from the front driveshaft. The front half shafts contain only CV joints on 88+ pickups and 92+ SUVs.

georgshe · February 20, 2007

ok, now i'm new to the whole 4x4 thing. i have driven a push button 4x4 before, don't know if it's different since the electronic sensors, etc, but i do know you have to be in neutral to shift to 4wd with a floor shift lever 4x4. and you have to be in reverse to shift out. but even if i was on dry flat pavement (which i was), it still shouldn't shake side to side like that right? cause on the push button 4x4 i drove before it went in 4wd one time when i went up a steep hill and when i got back on dry flat pavement it was still in 4L, but not shaking... and also, if it is a problem with the joints in the front driveline (meaning the driveshaft that runs from the front axle to the transfer case, i think....correct me if i'm wrong...) then that indeed would make sense that it wouldn't affect the 2wd operation since it is the driveshaft and not the axle...right? now, i guess i should mention too that the guy that owns it said that he replaced the...uhhh...well, now that i wanna say it, i can't remember, but it's one of the parts that make your front tires lean in...where it wears out the inner side of your tires...think maybe that could have affected the front driveline joints?

georgshe · February 20, 2007

As long as your not going lock to lock, it is very unlikely that you will break anything, especially with stock tires. The only concern would be if CV joints were shot, then they might break. But if they were shot, they need replacing anyway.

and what do you mean by lock to lock? forgive me, i'm new.really new... are you meaning not hitting reverse in between changes?... like if i wanted to go to 4H then 2wd. i would go neutral/4H/reverse/2 right? and then if i wanted to go from 2wd to 4H then 4L. i would hit neutral/4H/reverse/4L? do i only have to reverse out when i go from 2wd to 4wd? or hit reverse even between 4H and 4L as well?

Ranger · February 20, 2007

I think for electronic 4wd like yours, you only need to shift to neutral to get into 4-LO. 4-HI you can just shift whether in P, N, or D, whatever. I never really have to back up to get mine to shift into 4wd, I just select 4-HI or 4-LO, put it back in drive, give it a shot of gas, and boom, not stuck anymore.

And lock to lock means turning the wheel hard to either direction, like when you're doing a U-Turn or doing tight maneuvers.

georgshe · February 21, 2007

well, the truck i'd like to get is floor shift 4wd...and i'm trying to learn all of this at the last minute because i'm moving to west virginia and i'd like to be able to hear some opinions on the shaking in 4L since my mechanic can't look at it till thursday....i'm in a rush to sell my beloved 97 firebird because yea, i can really see me trying to drive in snow out in the middle of nowhere with it...ha! good luck, right? so this truck is within my price range, and fully loaded, and it's so far the best last minute find i've seen so far....car shopping is crazy....so i'm trying to weigh out if this shaking problem might be a couple hundred dollars to fix, or a couple thousand...no need to buy a 4wd that has no workable 4wd...if i have to buy a transfer case for a bit, then i could swing it, but not if i have to replace more than say 3.000 for the 4x4 to work...especially since this might me a truck i might only drive for about a year in the mountains, i don't want to needlessly spend a lot of cash for something that's truly not worth it. so i'd still need to know how to shift drive/4H/4L...but for a floor shifter...any help?

roy67ss · February 21, 2007

That truck you can shift from 2wd to 4hi 'on the fly' which means you don't have to be stopped to shift in or out of 4wd hi range. You do need to be stopped to shift to 4lo but it should shift whether in park, drive, neutral or reverse. The light on the shifter consol will tell you when it is in 4wd.

Sorry I can't help with the shimmy question for sure but it does sound like it could be u-joint problems with the front drive shaft or check the mounts for the front diff to frame. It is mounted by ears on the case to the frame. They are aluminum and part of the case. When in 2wd there would be no torque being applied to the front diff and it is just along for the ride but in 4wd it is getting torque and if the diff mounts are broken, it can move around some.

ericrlong · February 21, 2007

there's a 94 z71 sierra i'm looking to buy, and all drives fine when it's not in 4 wheel drive, but when i test drove it, it drove fine for a minute in 4H, but after switching out and into 4L, the whole truck shakes...and then after trying to change back into 4H, it still shakes...then when i change back into just drive it was fine again...the steering was fine, well, the wheel itself didn't shake, just the truck. i'm still willing buy it and get it fixed since it seems like only the 4x4 is affected, but i'd like to get an idea of what might be causing it and about how much it would cost to fix it...

Just a mention of my experience. I had to use 4 wheel drive on a snow covered dirt rd. Came to end of dirt rd and start of dry pavement.(2001 duramax). I forgot to take it out of 4 HI and started down dry, paved road. Felt like the truck was coming apart from front to rear. By the way, my truck at the time was new. Tires are never perfectly matched for equal circumference. Anyway, clicked out of 4 wheel drive and all is fine. I will mention that I traded my duramax for a five speed standard and 4x4 shifter on the floor. I like simplicity.