The wife traded vehicles with the boy so he could use her newer, more trustworthy car to visit his dad.

I got into it to back it up to load up something for her and saw that evil light looking at me. I immediately took it out of 4WD and backed it up. (I don't even know if the electronic hub stuff needs to be backed up)

As I was driving her to her goal, I heard a really bad rotational noise.

It's my fault for not giving her a primer on things. She has owned a 4WD vehicle before, but it was the manual type and she just didn't know.

What am I in for?

It's a 94 GMC Jimmy. "Push button" 4WD.

Thanks, folks.

 would start by looking at the cv joints...  

the truck had been lubed and maintained properly correct?   cycled into 4x4 every month or so?  front diff oil changed yearly?  Does son maintain it?  

Transfer case failed, especially if not all 4 tires were not exactly the same size. Never drive a 4WD vehicle in 4 wheel drive on dry pavement very far.

The transfer case used your 'T' truck had a chain with a clutch that applies it in 4 wheel drive, both are very weak points the transfer case.

However - it does say this in the owners manual:

Why would one assume all 4 tires are not the same size?

Answer to all is probably no. I bought it for myself for a project because it was ugly, but mechanically very sound a little over a year ago. His car kaboomed a week later and it became his daily driver to school (30 miles each way to school, minus his work detour).



He does have money saved for a vehicle, and I'm thinking he needs to use it. He's a really good, very smart, ( already offers from Vanderbilt and many other huge colleges as a junior) high school kid.

I think I'm going to lead him toward putting his money towards something that is much newer and more trustworthy that a vehicle that was designed more than a decade before he was born.  

I'll indroduce him to what us old guys ( that used to tune an engine by ear) when he's making money later on. He needs to concentrate on getting to class for now.

I'll still need to get this poor old Jimmy back in good shape. (Sorry for the random, and amazingly funny derail that I'll clarify when I calm down)

Let's assume that a kid (who I assumed would listen to me, duh) was told that AWD the same as 4WD and drove for months, thinking it was all the same.

The answers are coming out now that he's looking at being a senior riding the bus. His "smart" friend told him that 4WD" was really AWD and AWD was was more fuel efficient. (Remember when I said this kid was smart with his math!)

Because most are not the same size, all 4 tires need to be within 1" of each other on circumference not diameter.

If you read the owner's manual it says not to use 4 wheel drive on dry pavement.

Because he read the post that it's a 94 GMC Jimmy that requires the same size tires on all four tires to operate the ABS properly.

Full time 4WD wasn't always used to drive the vehicle, as we all know. The full-time four wheel drive was because we could pull the lever and have 4WD. The disconnect was done by the transfer case.

Precisely!!

I drove it for the first time in almost a year, yesterday. I did my best not to stress out the wife on the way to her job interview. I only told her after she was done.

I have driven hundreds of miles in 4-low locked front and rear with the rig bound up in most situations. It's fine, or should be.



If anything, you broke traction at a slip rate on the tires that is hardly perceivable.

Um, no, it's not fine.  Driving at very slow speeds, or offroad is A LOT different than running in 4WD on a dry highway for possibly months as a DD.

I bet it's just fine.

I doubt it messed anything up, maybe a cv joint  ball joint at worst if they were going out already.

My brother drove my dads old truck in 4low for a few weeks and nothing broke but my dad changed out oil in transfer case and check ball joints to make sure.

Meh. I drove 500 miles in 4hi on dry pavement to break in my 4.56 front diff gears.
My friend drove back from Colorado to Florida in 4HI in his Yukon with like 250K+ miles on it, and proceeded to drive it for several months in 4hi before realizing it. His idea of driving was 100% throttle or 100% brake, nothing in between. I think his Yukon had over 300 when he sold it for 3/4ton Yukon with an 8.whatever liter with a Whipple supercharper.

Oh Jesus H....it's fine. If something is fried then it was on its way out anyways.

Ok, guys. Sorry I took so long to get back to this.

Really bad rotational noise, probably coming from the driver's side CV shaft.

On top of this, he had ran it down to( at least) two QUARTS low on the tranny. I added a pint at a time and let it sit, running for at least 15 minutes between checking and filling.

This poor thing has almost 200k on it and he's abused it for at least 40k of it. I had it towed home yesterday because it lost third+ while leaving school.

I'll be testing what it does tomorrow on the way to the post office tomorrow, I already told his mom to have him figure out how he's going to buy a new car. He's been "borrowing" this thing for a year and never saved a drop after working all year. If he's not willing to work at it and learn, he's not going to be abusing my stuff, too.

For those wondering, I gave him the Chilton's manual and said to ask questions. Fluids have always been available here to use.

I also, just found out that the radiator has been damn near dry for who knows how long.

I'm glad I'm older and not as angry about things, anymore. If it'd been his older brother, I'd have been throwing things. It's also a good thing both he and his mom are out of town for a wedding.

I guess it goes to show that genius ( he's like top 1% in the state)does not equate common sense.

Sorry, I'm just extra pissy about his lack of responsibility.

Book smart as measured by a state curriculum is awesome but as you've discovered there are aspects of intelligence that are tougher to quantify. It's not uncommon for people gifted in one aspect to struggle with others. 

As for that poor abused Jimmy,  yikes might be quicker to list what isn't wrong.  Cooling systems on the 4.3 were always cursed by Dex cool. Something about that motor made the dex cool problem worse. Thing is probably full of sediment. Flush and fill. 

  Losing 3rd and up in the trans is no good, 4L60 gave up the ghost....junk yard unit or the cost of a reman is probably more than the vehicle is worth. If you really want a project you could rebuild it yourself...pick up an ATSG manual and go nuts.

 I doubt driving it in 4hi did anything bad besides beat up the tires.  GM 4 wheel drive setups are surprisingly tough.  My first thought on a rotational noise in the front would be wheel bearings. But shit, that's the least of your problems. 

Most people would walk away from a basket case like that but anything is fixable if you're willing to put in the work. 

Oh, it'll get fixed. If nothing else, it'll be my new fishing buggy.