2008 Tahoe Transmission Failure

[countrybumpkin]

2008 z71 Tahoe 135K, 5.3L 4x4.

Heard a loud clunk under my truck after harder than usual acceleration. The rear end started locking up and making straining noise. the truck has a history of locking up when it shouldn't, especially on a hard left, loose gravel, or turning around in a parking lot.

I go to take a right at the bottom of my street, another loud clunk and locking up. Lost 3rd and 4th gear.

Drove it up the street home in 2nd, then manually shifted into 3rd. Rear end was skipping and locking up my gravel driveway.

-Checked tranny fluid: Thin and a little high but no discolor, smell, or debris.
- Not running an codes on the dash. No 4x4 in 3rd and 4th gear

This truck was not babied: plenty of towing, numerous hunting trips, and extensive highway and city driving. I'm sure my transmission is cooked.. probably lost 3-4 clutch pack and solenoid failure.

I am more concerned about my rear end. Does anyone know what would cause it to lock up constantly? It has a G80. Likewise, why would it make such a loud clunking noise in the rear end after tranny failure, and why was the rear end acting funny (locking up, making a slipping type movement, loud clunks, tire squeeling) after the noticeable transmission issues?

I am looking for some insight on anyone else who has this experience. The truck is currently at a family friend's auto repair shop awaiting diagnosis. I need another couple years out of the rig, so also looking for suggestions to ensure I do not face this issue again.

I am a first time user on the forum. Thank you for input

 

[ccapehartusarmyINF.(ret)]

lets focus on the tranny for a sec
okay when you say lost 3rd and 4th gear
what happens when you take off on the freeway normally shifts 1st to 2nd fine i take it
how does it shift to 3rd do the RPMs spike between 2nd and 3rd or does it trys to shift to 3rd and it just revs up and goes back to 2nd or does it not shift at allto 3rd

 

[countrybumpkin]

Chris- Thanks for your reply.
The truck will only take off if placed in 1st or 2nd. Truck will not move from a stop if in 3rd or 4th gear.
It does not shift into 3rd automatically. After the loss of 3rd and 4th I was able to place the truck in 1st and move it. I was then able to manually shift from 2nd to 3rd, but if I came to a stop still in 3rd the truck will again not move. I did this only to return it to my driveway (broke down a mile from home), and I have not attempted any further movement except neutral to roll down my driveway and reverse to get it lined up for the wrecker.