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  1. #1

    Default 2001 Express 1500 LT....How to tell if it has positraction?

    How do I tell this as the VIN does not give it to me. Old spec sheets says it does, but I wanted to check to make sure. Vehicle has 160,000 and runs good. Has new rebuilt tranny and I am wondering about changing rear differential fluid. How often should this be done as the fluid must break down over time. No records of previous maintenance. Thanks.

  2. #2


    Rear fluid should be done every 60,000 miles I believe. And you can tell what rear end you have by the RPO codes in the glove box. The Gxx codes are the ones for the rear end. GUx is for the gear ratio and Gxx is usually the rear end type.

    - - - Updated - - -

    Just checked my owners manual and it doesn't actually specify a interval, but for severe duty applications they say do it every 15,000 miles so i say double that and that should be when you do it, but in saying this rear ends are build very tough and can handle neglect, so I don't think any damage has been done by not changing it as long as you have kept an eye on the level and kept it full.

    I just did a front diff fluid change in my truck and the fluid wasn't that dark after 200,000 miles of service.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage:

  3. #3


    The Lt version was a chevy factory upgrade with all captains chairs and does not have a glove box. Where else to look?

  4. #4


    Ok here are listed locations for where they may be. Left side under driver seat or Rear Face of Right Door “B” pillar face also Passenger Side Sun Visor, Side Wall of Cab, Behind Passenger Seat. With out the RPO codes its hard to tell what the vehicle has.

  5. #5


    Found it and I have the g80 locking diff I want to put new shocks on rear to raise it up a little. If I get another inch of clearance from coil shocks how big of tires can I go to? 265 70 15?

  6. #6


    I had 265-70-15's without any lift & zero rubbing issues on my 2002, but your speedo will be about 6 mph off & acceleration will suffer a bit. Went back to 235's after about a year & happy I did. With the 265's I was always wanting a gear ratio change. Ideal would have been about 4:01-1, but all I could find as next size up though is 4:11-1

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