65 Mph In 4w Low ?

pastorscott · April 12, 2009

Just got a phone call from my sister in CA - Im in NY. She called me because we both have 04 burbs.

She said - what does it mean when the light thingy on the 4wd low thingy is lit and the truck feels funny ?

Yike !!! I said , I hope to didnt drive it like that - well,,,, She did all day .

Question - how is that possible ? Does the computer pop it out after you get so fast ?

I got her to pull over and talked her through getting it back into 2wd. The service 4wd light came on then went out and she drove home with no smells or noises or any problems . I think the prayers helped

any takers

Scott

hockeypro1411 · April 12, 2009

So what I gather from that huge jumble of words and a title is that your sister drove the Suburban in 4lo at 65 mph? I don't think that's possible. Don't you have to shift into neutral to get it into 4lo and be rolling only a few miles an hour? Sure it wasn't 4hi?

svensk · April 12, 2009

So what I gather from that huge jumble of words and a title is that your sister drove the Suburban in 4lo at 65 mph? I don't think that's possible. Don't you have to shift into neutral to get it into 4lo and be rolling only a few miles an hour? Sure it wasn't 4hi?

RPMs would be screaming at 65mph 4-low?

Probably was only 4-hi. no biggie if that is the case.

mattgob86 · April 12, 2009

Well if its anything like i have experienced in 4 low, that is quite impossible. i think the fastest ive ever gone in 4lo was like 30 and even then it was spinning some serious RPM's

Griptruk · April 12, 2009

Yeah, I agree that she must have been in 4 HI, you'd have to be turning like 20,000 RPM to do 65 in 4 low. Still not great for the drive train if it was on dry ground, but not the end of the world.

MS3DALE · April 12, 2009

So what I gather from that huge jumble of words and a title is that your sister drove the Suburban in 4lo at 65 mph? I don't think that's possible. Don't you have to shift into neutral to get it into 4lo and be rolling only a few miles an hour? Sure it wasn't 4hi?

RPMs would be screaming at 65mph 4-low?

Probably was only 4-hi. no biggie if that is the case.

Yep,Bet she was in 4-HI....No biggie,shes fine.

nonotme42 · April 12, 2009

Worst case scenario, she probably got that transfer case and front diff good and hot, and MIGHT have done some wear damage to the front tires, ESPECIALLY if she was making any turns.

But, otherwise, its...probably ok...probably.

bigredmariner · April 12, 2009

Gotta agree, probably only in 4HI, I think some rods would have come out the side in 4LO at 65.

Rat4go · April 12, 2009

So here's my math.....4L60 in top gear of 0.7 spins 1700 rpm at 65 mph in 2 or 4 high. Transfer case ratio is really close to 2.7 in 4 low, so at 65 mph, she coulda been spinning 1700 x 2.7, which is about 4600 rpm. Dunno if the ECM allows it or if it speed limits the truck to something more sane. If no ECM intervention, there were likely no rods coming out of the block, but I bet the bearings in the planetaries in the T-case were PI$$ED if she spent much time there. If you're sure it was 4 low, change the transfer case fluid soon. Hopefully it's not too late and she'll only be out the 2 quarts of fluid that the transfer case takes.

Kazadog · April 13, 2009

Had an 04 Chev 2500 Duramax switch to 4 low at ~80 km out on a logging road while going to work . The truck stayed right where it was until the GM dealer came and got it and towed it back to the dealship. It was the push button auto track system that failed and the total cost to the dealership/GM was $500 for the tow plus a new drive line from front to back. My 01 chev auto track also quite while I was in 2wd, and that cost me $350 to get replaced. The auto track can screw up and cause lots of problems. I have mixed feeling about it, but have it in our 05. Keeping my fingers crossed!!!

Cheers

KD

BrockwayMT · April 28, 2009

I don't think you could get 65 mph. Usually 45/50ish is a fast as the will go. We had a 08 2500HD with MYC up to 56 mph the other day. That was at fuel cutoff, near to 6000 rpm. Low range planetary was singing pretty good. As long as the transfercase had oil in it and she didn't run it like that for hours it's fine. Changing the oil won't hurt, but it probably didn't get too hot anyway.