1999 GMC Z71 ext cab truck

[suzymathias53]

At the risk of repeating the problem.... I am just now figuring out where/how to post this .....

1999 GMC Z71 ext cab truck has the Auto 4WD light, the 2HI light AND the SERVICE 4WD lights on simultaneously and constantly. Truck seems to be running fine. Valvoline quick lube pulled plug on front diff and said there was Dex in with the diff. fluid. Refilled and told me to see the dealer for service. Can Dex really get into the diff? Do I have a serious problem? Am I fixing to hear crashing metal and smell burning fluids/gears if I keep driving????

[70camaro]

I am assuming by "Dex" you are refering to Dex-cool antifreeze? If so, I don't see how you could get coolant in your diff. Just the same, if your lights are on, there is a problem. I would take it to a GOOD mech. that you trust, not just the lube shop. They should at least be able to tell you what the problem is.

[suzymathias53]

Originally Posted by 70camaro

I am assuming by "Dex" you are refering to Dex-cool antifreeze? If so, I don't see how you could get coolant in your diff. Just the same, if your lights are on, there is a problem. I would take it to a GOOD mech. that you trust, not just the lube shop. They should at least be able to tell you what the problem is.

Actually, the Dex he was referring to is the DEXRON II/MERCON ATF fluid..... can transmission fluid get into the differential???