Hey All! Just bought an amazing 98 Smokey Carmel Tahoe with 250k on it. This truck is immaculate. Little to no rust. SPOTless interior. But it has 1 issue. 4x4 worked when I test drove it, now it doesn't. 350 v8, 4 speed auto with the 4 mode push button t-case.
Symptoms: Lights illuminate intermittently (even if the switch isn't illuminated it will still audibly trigger the front diff.) on the 4 button panel and behave as they should when pushed. 2HI will flash and engage 4HI light and so on, however the truck never engages 4x4 mechanically. So I did a few tests/replacements.
I knew the front diff thermoactuator commonly fails, so I replaced it (It was original). I can hear it trigger when I press 4HI or go back to 2HI. Next, I removed the t-case actuator and I had my wife trigger it to 4HI. The acuator moves, but very little. Maybe 45-60 degrees and when it was on the t-case I never heard it drop into gear. I removed the actuator and disassembled it and found no structural damages or anything that appeared damaged. The battery voltage is excellent at ~14.5-15v at the terminals running. I also removed and cleaned the contacts of the t-case electronic buttons. (This seemed to resolve the intermittent LED function)
I have already ordered a t-case actuator, I just want to make sure I'm on the right track here. The actuator appears original and the previous owner states he only used the 4x4 a handful of times over the last 13 years. At what point do I begin to suspect the T-case has internal damage?
My actuator is the style that has the 4 pin harness attached to the electronic motor and the 6 pin connector for the t-case position sensor.
Any help/advice would be appreciated! Thanks!
Symptoms: Lights illuminate intermittently (even if the switch isn't illuminated it will still audibly trigger the front diff.) on the 4 button panel and behave as they should when pushed. 2HI will flash and engage 4HI light and so on, however the truck never engages 4x4 mechanically. So I did a few tests/replacements.
I knew the front diff thermoactuator commonly fails, so I replaced it (It was original). I can hear it trigger when I press 4HI or go back to 2HI. Next, I removed the t-case actuator and I had my wife trigger it to 4HI. The acuator moves, but very little. Maybe 45-60 degrees and when it was on the t-case I never heard it drop into gear. I removed the actuator and disassembled it and found no structural damages or anything that appeared damaged. The battery voltage is excellent at ~14.5-15v at the terminals running. I also removed and cleaned the contacts of the t-case electronic buttons. (This seemed to resolve the intermittent LED function)
I have already ordered a t-case actuator, I just want to make sure I'm on the right track here. The actuator appears original and the previous owner states he only used the 4x4 a handful of times over the last 13 years. At what point do I begin to suspect the T-case has internal damage?
My actuator is the style that has the 4 pin harness attached to the electronic motor and the 6 pin connector for the t-case position sensor.
Any help/advice would be appreciated! Thanks!
