Any Automatic Transmission Experts ?

[175gr7.62]

My son has a 07 Avalanche with 256k miles. It was his grand paws and is a cherry. I had the tranny rebuilt at 200k because he was heading to college and knew that the 4L60E would eventually need to be done.

Here we are 56k miles later and it won’t shift from 3 to 4. My son came in today and took it by the shop that did the rebuild and they said the 3-4 clutch is gone and it needs to be rebuilt. In my experience when the clutches go bad it will slip like hell when it tries to shift. This transmission is even trying to shift.

I consider myself an above average mechanic and but will admit I’m not an auto tranny expert. Does this sound right? I’m thinking it’s a shift solenoid. I don’t know how you can say a clutch is bad when it doesn’t try to shift and you haven’t cracked it open.


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[Walker]

These darn trannys these days are all electronic. No telling what happens when clutches wear. Could be sensors wont let it even try to shift. I know nothing about transmissions so Id get a.second opinion.

[Sasqy]

I know how to tear them up
But that’s probably no help

[-HIC-]

The 3-4 clutch pack is a common problem on the 4l60. You actually may have caused the issue with the rebuild. The main issue being low line pressure as that circuit is used for every gear except R and 1. Any internal leak will accelerate the 3-4 pack slip and burn.

Does the fluid contain the remnants of the clutch pack? At 58k the fluid should be bright red with little indication of clutch lining. If it has a large amount of clutch lining in the fluid the trans needs to be rebuilt. The problem is if it not rebuilt correctly you will be in this place again.

If the fluid is clean you may have a solenoid issue or other problem.

[-HIC-]

I have a line pressure tester that I will ship to you if you want to check it before making a decision. Just make sure it comes back! :0

[D u s t y]

I’ve had one drop the 3/4 pack. It would go from park to 1 with no problems then to 2with out a hitch then once it went to third there was nothing. Drove it for 2 weeks in 1/2 before buying a transmission out of a junk yard for 450 drove it another 60k miles and sold it.

[D u s t y]

Check the fluid see what color it is and how it smells