Front Differential Problems

Not with the problems you describe. I am thinking that maybe your truck slipped out of the factory with two different axle ratios because of a assembly line screw up. It would cause what you describe.

Not unless it changed during/after the 5 miles he made it! :)

Get all 4 wheels off the ground firmly & safely (jack stands, etc). Stick in 4 wheel, and see if you can get the wheels to move. See if you can rotate each front wheel freely.

If the 5 miles was in slick snow it would have worked and it would have bound up on dry pavement. THe only other possibbilty here is front diff has no lube in it or Tcase is dry (not likely either) With GM 4x4, the driver side front wheel is always engaged to front diff and the ride front has a disconnect at the axle housing so if thw wheels were binding it would still bind in 2wd. A thing to note and remeber here though is that GM can be very fussy about warranty work on drive line problems with lifted trucks. I have a 2000 K3500 old style with a snow plow and they have never said a word about that because truck is stock otherwise including tire size.

Those aluminum IFS front diffs are pretty weak, but I don't believe the dealer is telling you the truth. Unless they actually took the front diff out, how do they know it's worn out? I have an older IFS front end truck and there is no inspection cover, the diff splits in half (right and left sides) before you can inspect the ring and pinion. If the ring and pinion were bad, it would make a hell of a raquet for some time before locking up. You would hear a whine at first, then as the gears eat each other up the noise would change to grinding and popping.

I've got a 6 inch lift and 35" tires on my truck so I can attest that the front diff will take some punishment - and 4000 miles is peanuts.

I have heard of the drivetrain completely locking up before one other time. A friend of mine was with his father at the dealership test driving a new Denali and while driving down the street, not too far from the dealership, the entire thing came to a screaching halt. After lots of messing with things, they couldn't get the truck to move at all, so they walked back to the dealership.

Take John's advice - get all four tires off the ground and try to find out where things are binding. With 4wd engaged, disconnect the front driveshaft and see if the transfercase will turn freely, and that will tell you if the problem is in the front diff.

One other thing - if the front diff does turn out to be a problem, consider buying a used one instead of getting that one fixed. I was planning on selling mine so I looked for prices on ebay, and found they were going for around $100 to $150. That's way cheap compared to getting it fixed, because it cost me around $700 just to have the front gears changed from 3.73 to 4.88 (nothing broken, no troubleshooting, etc). Keep in mind I'm talking about a little bit older truck, but unless something changed for 2005, your front diff probably matches ones from a few other years.

SuperDave

Those diffs are not weak and you will tear the half shafts off before you damage the 9.25 diff in a 2500 truck. It is pretty stout.

SuperDave wrote:

A friend of mine had a Bronco II that did that... she was driving and suddenly the whole drivetrain locked up completely. It was like she'd slammed on the brakes.

She took it to the dealer, and they basically said they'd heard of it, but it was a 1 in a million thing, and not to worry, that it wouldn't happen again...

Unfortunately it did... Get it looked at ASAP.

~jp

SnoMan, you might well be right. The one in my truck is the aluminum type that came in the 1/2 ton trucks and it is known to be weak - it's got an 8.25" ring gear, and simply torquing the case housing bolts down will distort the case enough to affect the gear meshing pattern.

GM did not physically install the lift kit. My truck was lifted by A&J conversions from Valders Wisconsin ( AJvans.com ). I called them and they told me that the lift kit they installed was completely covered by my GM warranty. They buy trucks directly from GM at which point they lift them and so on and so on. My dealership does now have a new front differential on order. They say now that this part never goes out so GM doesn't make extras. In 3 weeks it should be at the dealership. They told me now that they want to sue A&J to cover my warranty. I think my dealership is horrible. I'm currious to see what happens. One of my friends heard GM has had trouble with the four wheel drive on new diesels. Apparently they installed faulty bearings in some of the front differentials and have had some problems. Who knows though. Hopefully they don't find anymore problems when they replace the front differential.

You cannot even fit/mount the 9.25 front diff in the 1500 truck (except the 1500HD which uses a 2500 chassis) as it is a lot different. Never seen it done yet either with modification. That same ring and pinion used in the GM 9.25 IFS is used in the AAM solid front axle that Dodge has been using since 2003 in its HD trucks.

I have a neighbor that had the gears in his truck changed, he went to 4:11's or so he thought. They put 4:11's in the back and 4:88's in the front. In a snow storm he put it in 4hi he drove for about 10 miles then hit one dry patch in the road... the transfer case was the week point and there he sat. So it could possibly happen... but there are a few other things it could be too...