2004 Tahoe Z71 falling off into netural while driving

[jyates1959]

My 2004 Tahoe Z71 is always used in 2 wheel drive and it has that push button cluster on the left side of the dash. I keep it in 2 wheel and I've caught it dropping off into neutral (the shift indicator is still in D) while driving on interstate. I have to pull over and turn the key off and start it again and put it back in D and away we go but after a while of driving it will do it again and again.

The only fix I've found to stop it is to run the Tahoe in Auto 4wd. I carried it to the chevy dealer but they couldn't find a "code" and they drove it around town and it never did it in town. So they didn't do anything about it.

Perhaps it happens at 70 to 75 mph and it won't happen in town or on normal highways.

Does this ring any bells with anyone?

Thanks,
Jim

 

[tsuintx]

Change the switch cluster. That is known to fail and cause issues. For me that has helped get rid of 4WD related issues in two different GMT800 SUVs.

 

[jyates1959]

Change the switch cluster. That is known to fail and cause issues. For me that has helped get rid of 4WD related issues in two different GMT800 SUVs.

You are talking about the switch cluster on the dash could be the problem?

I looked on Ebay and saw some switch clusters listed there. I may pull the dash bezel off and see what kind of part number is on my switch. I saw some used ones that looked the same as my layout but I think I would be better off buying a new one to make sure I don't get one with the same problem I already have!

Thanks,
Jim

 

[tsuintx]

Yes, that one. I'm not saying that IS your problem, but that's the easiest one to swap and does go bad, so might as well...

I wouldn't buy a used one since even the new ones are not that expensive. If you are in a rush, you can even by them from your local parts store. Costs a little more, though.

 

[jyates1959]

Yes, that one. I'm not saying that IS your problem, but that's the easiest one to swap and does go bad, so might as well...

I wouldn't buy a used one since even the new ones are not that expensive. If you are in a rush, you can even by them from your local parts store. Costs a little more, though.

Thanks for the advice. I'll try that!
Jim

 

[jyates1959]

Once I got back in town I caught it slipping out of gear again so I've just been running it in Auto 4WD and I ordered a new switch cluster and put it in, but it still slips back out of gear just driving around town and you have to pull over and put it in Auto 4WD and then you can put it in 2WD and it will go for a short distance before slipping back out of gear.

Keep it in Auto 4WD and it works fine with no problems. It just can't substain staying in 2WD.

The dealership had run a test but didn't see any "codes".

Any ideas?

Jim

 

[OR VietVet]

Is there a relay for that system? If so change it. Your problem is intermittent. Encoder motor? Best if can test when is failing. That is one lazy dealer that didn't go any farther than checking for codes. C'mon man!
If is in the failed mode when they have it they should be able to check for what signal is missing.

 

[jyates1959]

Is there a relay for that system? If so change it. Your problem is intermittent. Encoder motor? Best if can test when is failing. That is one lazy dealer that didn't go any farther than checking for codes. C'mon man!
If is in the failed mode when they have it they should be able to check for what signal is missing.

I had told the dealership about it slipping out of gear and having to run it
in auto 4wd a couple of weeks ago when I had it in their shop replacing the heads and they "said" they drove it around quite a bit and it never failed for them...and they checked for a "code"....and it's true.....when I got it back after the head job it was in 2wd and my wife drove it for about a week without any problem but once we made a road trip on interstate and I was running about 75 then the problem happened and I've been able to make it do it pretty quickly ever since then even when driving 25 to 30 on a city street. I first had this problem about a year ago and it happened at interstate speed and then would slip out on the city streets so I just put it in auto 4wd and have been driving it that way ever since.

It was like it had "healed" itself by being run in auto 4wd only for the past year and it worked in 2wd for a week or so and then went back to acting up.

In park with just the ignition switch turned on (not cranked) I can switch from auto 4wd to 2wd and back and forth and hear a whirring sound when I press the buttons coming from underneath the Tahoe.

 

[OR VietVet]

That noise is the encoder motor. I know this will sound crazy but you need to hope it messes up on a more regular basis and take to dealer when it is and say, "Jump in here and see what I am talking about." The worst things to look for are intermittent problems.

 

[jyates1959]

That noise is the encoder motor. I know this will sound crazy but you need to hope it messes up on a more regular basis and take to dealer when it is and say, "Jump in here and see what I am talking about." The worst things to look for are intermittent problems.

I think it's back in the "habit" of doing it now so I'll have to get my hands on a service tech and show him what it's doing.