2000 silverado front end binding

[Thunderbolt]

I am still working on this POS. I replaced a bad front differential in this Chevy 1500 because it was banging and grinding. I put a used one in and it was making noise and binding even in snow. They gave me another one and it is no different. The bind is so bad that from a dead stop with any turning of the wheel it feels like something is going to break. If I let of the gas while going slow with the wheel turned the truck will stop as if the brakes are on. If i shift to 2 hi without touching the gas it will immediately start rolling. This isn't the normal bind of a 4wd, it is severe. The salvage yard insists it is the correct gear ratio, but I am wondering, although the odds of them being wrong twice isn't likely. Any ideas ?

[Thunderbolt]

New update. The tag I have from the salvage yard has the vin so I called gm. It is from a 2002 Tahoe with 3.73's. Highly unlikely they were changed, but I will still check.

[BenK]

since suspect wrong front diff ratio...without taking the effort/time to count
the teeth and divide...

Remove the front u-joint so the front diff is free

Tie a length of string on the front diff yoke

Roll the vehicle one tire rev using the valve stem as reference

Count the number of full turns and fractions of a turn the string made. That is
your diff ratio and no matter what tire size

Remove the string (gotta say that, as one on this forum got pretty made that his
string got all over the place...)

Ditto the rear with the front u-joint removed...

[Thunderbolt]

Well as I suspected they said they don't know what it is, but don't think it is the differential. I don't even think they checked the ratio. I stopped at another shop on my way home and they said it is sounds like the front. They suspect it is the wrong ratio. My next step is what you guys suggested and I will check the ratio myself.If it is the correct ratio then I am stumped.

[enblethen]

I am just getting old!I haven't had Chev since well before 1987.
My 4 wheel drives are controlled at the differential.
OPs issue is when turning which should be in front end, not transfer case.

[trail-explorer]

enblethen wrote:
Does your 4 wheel drive engage in the front differential or do you have hubs?

GM trucks haven't had hubs since the square body style, which was 1987 on non crew cab trucks.

[Me_Again]

Thunderbolt wrote:

Turtle n Peeps wrote:
Pull the rear drive shaft and drive it. See if it binds on just the front pulling. If so, at least you know it's in the front end.

The salvage yard I got the differentials from is also an auto shop. They are going to drive the truck today and see what they think and then I will go from there. Pulling the rear shaft is a good idea.

So have them do the test I noted above. Chris

[Thunderbolt]

Turtle n Peeps wrote:
Pull the rear drive shaft and drive it. See if it binds on just the front pulling. If so, at least you know it's in the front end.

The salvage yard I got the differentials from is also an auto shop. They are going to drive the truck today and see what they think and then I will go from there. Pulling the rear shaft is a good idea.

[Campfire_Time]

On the original was the fluid changed according the schedule in the manual? As I recall it's every 30k. If not, that could have toasted it. Since you got 2 used replacements, you have no idea when those one was changed. GM 4WD systems are very temperamental when fluid isn't changed regularly.

I agree with the others, this is more likely a gearing difference.

[Turtle_n_Peeps]

Pull the rear drive shaft and drive it. See if it binds on just the front pulling. If so, at least you know it's in the front end.

[Me_Again]

Put it on a frame hoist in 4 wheel drive and neutral or you could block it up at home. Mark all four tires at the bottom and turn them all together one revolution, and see if front and rear end up with the marks back at the bottom. Might need some helpers.

Chris

[Thunderbolt]

#40Fan wrote:
If your 4x4 selector switch has an Auto mode, I am sure your T-case is now toast. This really sounds like a wrong gearing situation. Have you owned this since new? What gears are the junkyards telling you it should have? You can jack one of the rear wheels off of the ground, with the transmission in neutral, and spin the tire 2 times while watching the driveshaft. Mark and count the number of times the driveshaft spins to the two turn of the tire and it will give you a close estimate of the rear gear ratio. Is that close to what they are telling you that you have?

Brother in-laws truck and owned since new. Truck has 3.73's. Gt4 in glove box and the truck runs at the same rpm as my truck with 3.73's.

[Thunderbolt]

45Ricochet wrote:
Not sure about your year but is pump rub a possibility?
At 350k miles I'm pretty sure your truck isn't still purrin' like a kitten.
My money is on a different ratio though.

No leak in transfer case and it is full with Auto trak fluid. I know there are clutches in the T-case and I haven't ruled that out yet. This thing is binding so bad on even a slight turn in gravel that if I let off the gas the truck stops. If I step on the gas to go it practically spins the rear tires to make it move.I know the truck has 3.73's and 4.10 was the only other option, but I didn't think they were very common. Did Suburbans or Tahoes come with 3.42's ?

[Thunderbolt]

dodge guy wrote:

Thunderbolt wrote:

2003silverado wrote:
Just to be clear...if driving straight in 4 hi will it bind?

No binding going straight, but growls when slowing to a stop. I am wondering if I got two bad differentials. Maybe carrier bearing bad ? That or wrong gear ratio.I am honestly at a loss.

Sounds like normal 4WD binding to me! that`s the way it works. try it on loose gravel and I bet it feels more normal.

Does it even in snow. It is not the normal binding. I know that feels like and this is much worse. I am wondering if the outer cv is broken inside the boot. I couldn't feel anything with my hands, but under a load maybe it is pulling apart ?

[dodge_guy]

Thunderbolt wrote:

2003silverado wrote:
Just to be clear...if driving straight in 4 hi will it bind?

No binding going straight, but growls when slowing to a stop. I am wondering if I got two bad differentials. Maybe carrier bearing bad ? That or wrong gear ratio.I am honestly at a loss.

Sounds like normal 4WD binding to me! that`s the way it works. try it on loose gravel and I bet it feels more normal.

[45Ricochet]

Not sure about your year but is pump rub a possibility?
At 350k miles I'm pretty sure your truck isn't still purrin' like a kitten.
My money is on a different ratio though.