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probs with transfer case? questions about new truck

Discussion in 'Chevy Trucks' started by 85chevy3/4, Mar 12, 2002.

  1. 85chevy3/4

    85chevy3/4 Junior Member
    Messages: 8

    I just found this site and have some questions on my truck I just bought last weekend. It is an 85 chevy 3/4 ton 4x4. I bought it at an auction for 600 bucks. The body is in excellent condition with no rust. The interior sucks but I plan on fixing it. I want to put some money into this thing and just need to find out more about it. I would like to add a lift and possibly some 35" tires. It runs good, has a 350 motor with an automatic 3 speed tranny. There is no drive shaft for the front end so the 4wd doesn't work. When I shift into 4wd it grinds and won't even move. What could cause this? I have no background on the truck. What transfer case does it have? How do I know which one it is? What axle should I upgrade too or should I stick with the stock axle? Thankyou for any help you can give me.
  2. 75

    75 PlowSite.com Addict
    Messages: 1,382

    You can find some more info regarding your truck at www.chuckschevytruckpages.com , such as identifying which transmission you have by the shape of the pan.

    Is it a "heavy" or "light" 3/4 ton? "Heavy" 3/4's have a full-floater rear axle, identifiable by the hub with 8 bolts that sticks out past the rim. "Light" ones have a semi-floater rear axle, with no hub sticking out. If it's the "heavy" one with the full-floater axle, I don't see any need to change. Keep in mind if you are thinking of an axle upgrade that the front and rear gear ratios must match, IMO you are best off trying to find "mates" (front and rear axles off the same truck) if you intend to swap axles.

    I'd be guessing you have a 208 transfer case in your '85, unless it has been swapped out by a previous owner. Not sure on why the transfer case isn't working properly, you mention you don't have any background on the truck - I'm just wondering why is the front shaft missing :confused:
  3. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    It seems being an 85, it would have a TH700 trans, and the NP 208. Since 85 said it has a 3 speed auto trans, it leads me to believe it was swapped for an older trans/t case combo. The front shaft didn't fit, so they left it off.

    Just guessing.......

    What would cause the not moving in 4wd, could be an improperly adjusted shifter linkage. Sounds like someone did a fast trans swap before the auction. If the body is that clean, you still got a good deal, no matter what it needs. A rebuild from the ground up would still be cheaper than a new 3/4 ton truck.

  4. wolfie

    wolfie Senior Member
    Messages: 174

    when he said 3 speed it led me to believe it's an 8600# GVW truck... they had the TH400 tranny up to and including 1989. I'm not sure what transfer case it would be I know the 30 series used the 205 in 85 and the 20 series used the 208 but the 8600# truck might have used the 205.
  5. plowking35

    plowking35 2000 Club Member
    from SE CT
    Messages: 2,923

    the truck has a TH 400 and NP 208 from the factory. My 86 had the same drivtrain.
  6. 85chevy3/4

    85chevy3/4 Junior Member
    Messages: 8

    Thanks for the help guys. I looked under the truck last night and it has a 208 transfer case. It has hub caps on it now and I haven't had a chance to take them off to see what is underneath them. I messed around with the transfer case last night. I can move the front differential a little and the cv joints engage at the same time so the front looks okay. I can turn the yoke on the transfer case freely when the truck is in park. When I try to engage 4wd it doesn't move and just makes a grinding noise and the truck will not move. I bought a manual for it and I will try to adjust the linkage this weekend. Also where is an excellent place to get parts? It needs a new rear sliding window, door panels, seat, carpet, and dash. What is a good carb to run on this truck? It has the stock rochester 2 barrel carb. I plan on buying a k&n filter this weekend. Is that a good investment or is there something better. Thanks for all your help.
  7. staley52

    staley52 Member
    from Iowa
    Messages: 98

    the fact that it has a 2 barrel carb makes me belive it is a replacement motor that could be the reason for no driveshaft

    now about the t case pull the hub caps do you have auto or manual hubs are you shifting into 4x4 in neutral park or drive
    the 208 is supposed to be a shift on the fly but I have found the best way to shift is trans in neutral on level ground foot off brakes this also extends the life of tcase

    from 83 to 87 the th350 was standard equiptment and the 400 and 700 optional in late 87 I believe the 700 became standard for all but 1 tons and diesels and 400 the heavy duty option
  8. plowking35

    plowking35 2000 Club Member
    from SE CT
    Messages: 2,923

    Since you have the 208 case, my bet is that you have an under 8600 gvw truck??
    My 84 came with the 700r4, but had a TH 350 swapped in after the 700r4 got tired. Which in 84 was probably in about 10K
  9. 85chevy3/4

    85chevy3/4 Junior Member
    Messages: 8

    new truck

    Sorry it's a stock rochestor 4 barrell carb. I worked on the truck last sunday all day and looked over everything. I fixed the transfer case problem. It was just the linkage. I adjusted it about an inch and it shifts into 4wd just fine with no grinding. I am trying to figure out what drive shaft it had in it now. It doesn't have the rear hubs sticking out past the wheels so it's not the heavy duty 3/4. It also has automatic locking hubs. I have looked everywhere to find what drive shaft it had but no luck. I've called around to my local drive shaft shops and they quoted me prices from 200 to 300 bucks. Is there any place cheaper?
  10. Txstruck

    Txstruck Junior Member
    Messages: 26

    Good Deal?

    I just bought an old ex army truck 86 3/4 ton 4x4 V8 Diesel, only 26,000 miles, brand new ATV tires, everything works. well everything isnt much on a government vehicle, but like the other guy, i need to replace pretty much all the enterior and add some features, like AC, radio, real guages not just idiot lights and since we just got about 3-4 inches of rain in the past 2 days, im going to go test the 4wd out this weekend :D