2003 Trailblazer sticks in 4 lo, Tranman help?

chevrolet
trailblazer

#1

I have never had a problem before, but after towing the boat out of a sandy launch in 4 low I flipped the switch to 2wd, and did not notice the indicator light did not go to 2wd.



I saw I was at 4k rpm at 50 mph and pulled over only to notice the switch was in 2wd, but the indicator light was in 4lo. Auto 4wd seems to be fine and I think I can live with that as needed, let it go or fix something?


#2

Got it out of 4 lo after a few restarts and setting the switch to 4 hi where it went ok, then 2wd where it went ok


#3

That’s the transfer case, not the transmission. Are your 4 tires exactly the same size? If the front and rear axles are not turning at exactly the same speed, the servo-solenoid can not shift the T-case. Sometimes backing up a few feet will let it shift.

These “push-button” 4WD systems have been problematic from day one. When you add “automatic locking hubs” the problems are compounded…


#4

A few things I’ve learned from the Autotrac system on my 2000 Blazer.

I rarely put the Blazer in 4Lo. To shift in and out of 4Lo the Blazer has to be in neutral and moving less than 2-3 mph. It’s easier to shift from or to 4Hi as you discovered.

A Chevrolet tech mentioned it’s a good idea to shift to 4wd once every week or two. The Transfer Case Control Module (TCCM) locks up if not exercised. To reset the TCCM, disconnect the wiring harness at the TCCM (inside right kick panel) or disconnect the battery for a few minutes.

Check the vacuum line under the hood, at this age they may be rotting out.

Good luck,

Ed B.


#5

Recent oil change and check showed tires extremely close due to tire rotation of course. Within a few hundredths, but would have to check with the service guys as I do not have the checklist handy.


#6

I may never put it in 4lo again as the auto works fine in snow, why not on the beach. I had followed the 2 to 3 mph guide but in an ignorant everything is fine did not check the lights as it had always worked before. I will check the vacuum line, Try and exercise it in my own back yard. Thanks for the input. Test drive around the block all seems fine now, back burner I guess.