GM Allison Transmission?

You'll be on your own for any repair as you're out of any sort of warranty because of time.

I'd take it to a transmission shop rather than the dealer.

The warranty was probally 5 year/ 100,000 miles. That means which ever comes first. And you are way past the 5 years.

Are you sure it's the transmission and not the transfer case? Google "pump rub".

wnjj wrote:
Are you sure it's the transmission and not the transfer case? Google "pump rub".

Good suggestion about the transfer case. Allisons about that vintage are notorious for pumps rubbing a hole in the housing. Usually most discover fluid on the drive before they are trashed, but if it is to the point of being super noisy you are probably past just a case replacement or repair.

Some have had luck repairing the case, but that's way too much work for me to take a chance on it. I replaced my own for about 275.00 with
an aluminum one. ( original is magnesium and very soft )

Just check the case for fluid and that will tell the tale about that.

As far as the warranty, I'm afraid you are out of luck on that.---- Good luck.

The symptoms are a flaring when shifting and a loud clunk when you come to a stop.

Yes there is fluid at the transfer case where the small shaft enters. The Transfer case fluid was changed 5,000 miles ago.

So what does this possibly mean? Does it mean that it might be the transfer case and not the transmission?

Also, for the person who repairs my transfer case, what "exactly" do I tell them they need to do so that any "pump rub" issue does not happen again? I intend to keep this truck another 15 years.

Jeff,

I had diagnostics and servicing on my Allison trans (03) done
at a local W.W.Williams. Excellent service. Magnets and screens
clean. Fluids replaced. Did not have to have anything done to the
internals. I did not trust the local Chevy dealer to work on my trans.

Just a thought... let the guys that work on them all the time take
a look at yours. I was glad I did. Good luck.

Charles

More info on pump rub here:
Pump rub kit

jefffoxsr wrote:
Also, for the person who repairs my transfer case, what "exactly" do I tell them they need to do so that any "pump rub" issue does not happen again? I intend to keep this truck another 15 years.

Unfortunately, you can tell them anything you want. I am sure they will fix it the best way known. In reality they can't re-engineer it if there is an inherent problem. They can only do their best. If this turns out to be the problem, I would interview a few shops and see how they would fix it. Then make a decision on who should work on it...

B.O.

jefffoxsr wrote:
The symptoms are a flaring when shifting and a loud clunk when you come to a stop.

Yes there is fluid at the transfer case where the small shaft enters. The Transfer case fluid was changed 5,000 miles ago.

So what does this possibly mean? Does it mean that it might be the transfer case and not the transmission?

Flared shifting doesn't sound like a transfer case problem. I'd say it's time for a tranny shop.