2006 Tahoe pops out of gear

[300RUMCustom]

2006 4wd Tahoe Same old 5.3L engine with the 4L60E tranny. It keeps popping out of gear. I can drive it for weeks no problem then when I'm driving down the road it looses all gears. No forward or reverse. I put it in neutral push the 2wd button I can hear a clunk and then its fine for another week or month or a few days. Any ideas???

 

[B-train]

It sounds like you need a Tech2 or equivalent to see if there are any codes stored for the TC. How many miles? What has been the service regimen for fluids?

 

[strutaeng]

Sounds like it could be transfer case? Is this the AutoTrac? Is the fluid at the proper level? Also transmission level. How does the fluid look?

What is the history with the truck?

 

[89Suburban]

@NickTransmissions

 

[300RUMCustom]

It sounds like you need a Tech2 or equivalent to see if there are any codes stored for the TC. How many miles? What has been the service regimen for fluids?

I purchased a Matco Mazimus scanner on ebay scanner broken got it for 100$ I got that going and here are the codes I get. As far as Fluids and maintenance I just got it used so it would be guesswork. The tranny fluid looks old and tired so I will get that taken care of I am still going through the Ground Straps some are missing some are bad. I also noticed the cover on the TCM is off and looks a little crusty. I sprayed it down with WD 40 just to keep the water off it Im in Colorado so not much rain. The Head unit is sometimes on sometime not working. I do get the T/C light on the instrument panel along with airbag warnings and ABS warnings.

 

[rockola1971]

Looks like you got a weekend you need to be laying underneath a Tahoe. The Tahoe isnt popping out of "gear", that would be your transmission. Its your Transfer Case going into neutral because its encoder motor position is lost. Remove your encoder motor and replace either the range position sensor on it or the whole assembly and that should take care of your popping into neutral. Youve got some troubleshooting to do on your 02 sensors. Check their fuses first for their heater circuits.

 

[NickTransmissions]

I purchased a Matco Mazimus scanner on ebay scanner broken got it for 100$ I got that going and here are the codes I get. As far as Fluids and maintenance I just got it used so it would be guesswork. The tranny fluid looks old and tired so I will get that taken care of I am still going through the Ground Straps some are missing some are bad. I also noticed the cover on the TCM is off and looks a little crusty. I sprayed it down with WD 40 just to keep the water off it Im in Colorado so not much rain. The Head unit is sometimes on sometime not working. I do get the T/C light on the instrument panel along with airbag warnings and ABS warnings.

Thinking you have two entirely separate problems, the TCase encoder motor sensor / assembly and a transmission issue.

P0894 is the later model equivalent of code P1870 for the 96-2000 units (Component Slipping) which will store when the ECM senses a gear ratio anomaly in the trans...For the 4L60Es all years 1996+, it's usually one or more of the following:

- Valve body - worn TCC regulator bore (isolator and regulator valve)
Fix - Remove valve body and install Fitzall valve A74741BC to convert PWM to On-off TCC mechanical apply and seal off bore

- Torque Converter clutch failure
Fix - overhaul transmission if it's not been overhauled in the last 50k miles or so; install new TC

- Excessively worn Pump body and / or stator bushings
Fix - overhaul transmission - ensure all bushings, including the three pump bushings, are replaced (among other things)

What specific transfer case code(s) do you have?

Once you get your TCase issue squared away, hook up your scanner again and take it for a ride with the scanner showing live transmission data streams. Pay attn to Torque converter duty cycle and/or efficiency to see what values you see when in third and fourth gear. You'll notice if it's slipping while TCC is commanded 'on'. You can use that scan tool to clear the Chassis code being generated for the transfer case issue(s) once you replace the bad parts there.