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4x4 manual transfercase

Discussion in 'Chevy Trucks' started by MatthewG, Nov 27, 2010.

  1. MatthewG

    MatthewG PlowSite.com Addict
    Messages: 1,400

    My manual for my 04 2500 with 4x4 on the floor states to engage 4wd while in motion. I have always put the truck in neutral and stopped, fearing damage.

    But the manual wouldn't lie. Anyone have any thoughts?
  2. BlizzardBeater

    BlizzardBeater Senior Member
    from Maine
    Messages: 420

    Stop and put truck in neutral for engaging 4lo. 4hi can be engaged in motion up to 45 miles an hour.
  3. maverjohn

    maverjohn Senior Member
    Messages: 902

    Also if you are rolling and pull it into 4hi let off the gas pedal so it don't slam into gear
  4. got-h2o

    got-h2o 2000 Club Member
    Messages: 2,440

    You can put it in at any speed. It automatically won't engage till it's in its "safe zone".
  5. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Just posted this on another forum earlier....

    As for shifting procedure - very simple.

    2hi to 4hi - I found they shifted best when moving, in drive. In theory you can engage at any speed, but I always tried to do it under 25-30 mph. Just keep your foot steady on the gas (unless you are already spinning) and pull back firmly and steady on the lever into 4hi. Don't yank it as quickly as possible, but don't take all day either.

    4hi to 2hi - just give the lever a push forward at any time. Moving, parked, braking, etc. All you are doing is disengaging the dog clutch that drives the chain.

    2hi to 4lo - Transmission HAS to be in neutral. Try to do it in drive and there will be some very ugly noises. So - trans in neutral only. Once again, a smooth quick shift directly from 2hi to 4lo. Do NOT stop at N. It's optional/acceptable to shift ranges with the vehicle stopped or rolling slowly. May want to do some testing. Had a couple vehicles that shifted ranges better dead stopped, others shifted better rolling slowly.

    4lo to 2hi - reverse of above.

    If you put the case in neutral for what ever reason, just be patient going back into 4lo or 2hi. If the case is in N, and you put the trans in D or R, the trans tailshaft will be spinning. And it will spin for a long while after shifting the trans into N. You can put the trans in park and let the parking pawl click away till it stops, or shut the truck off. Do NOT let the case do the grinding. The input shaft on the case will not be happy.

    Finally - transfer case maintenance. These cases have a huge problem with the fluid "misting off". It's not uncommon to find them down by 1 1/2 quarts. And they only hold 2. If the fluid age/condition is unknown, change it. ATF is the prescribed fluid. Full synthetic is best by far. If the fluid is very nasty, put some cheap ATF in, drive it for a couple weeks. Then drain and refill with the good stuff.
  6. MatthewG

    MatthewG PlowSite.com Addict
    Messages: 1,400

    Thanks for the good info, not to sound like an idiot but is there a dipstick to check the fluid?

    Also I noticed my transfercase lever has moderate play in it more so than my 06
  7. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    No dipstick. There is a fill plug and drain plug on the back of the case, driver side. It's either a 30mm hex, or an allen head. 3/8 or 10mm. Fill through the upper plug till it runs out.
  8. MatthewG

    MatthewG PlowSite.com Addict
    Messages: 1,400

    Thanks just drained and refilled with some super tech gm ATF
  9. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Excellent. Did you happen to measure about how much came out?
  10. MatthewG

    MatthewG PlowSite.com Addict
    Messages: 1,400

    1- 1.5 quarts, it was very thin and had a silvery sheen to it. Im sure it was never changed.

    I did the motor oil, trans oil, and now this, so my truck is pretty happy.
  11. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Very good. I bought a 95 Tahoe a few years ago. One owner, 140K. We put two quarts in the t-case just to "top it off" LOL. Never made a peep, shifted perfect for the next two years.