transfer case

[rwenzek94]

got my truck up and going. when i first tested 4 wheel drive it worked and the light came on. now the light wont come on and when i have the lever in the 4 wheel drive position only the back tires spin..its only been a few days...anyone have any ideas???!!!? i NEED 4 wheel drive. thanks for any help

[BradMph]

Very first thing.. put the truck in park with the shifter in 4-wheel drive, lift one tire and see if the front drive shaft spins. If the front shaft spins then the transfer case is not engaging or poping in and out whenever. You may be hunting down a front axle problem when it is the transfer case or vaccum.

Park truck and in 4wheel drive, jack up the front. If your front shaft spins then stop right there because you have a problem in your transfer case. If the front drive shaft does not turn then your transfer case is locked in place and next step is test for vaccum.

Disconnect the 2 vaccum connections. Start your truck and you should have significant vaccum on one of the lines, Hopefully. Then with the truck running put your transfer case in 4 wheel drive (4low or 4 high) and vaccum should be cut off and the other line should now have siginificant vaccum. If this don't check out o.k. then one of your lines are cut. If it checks out ok, check your vaccum disconnect on front axel.

Worse case is broken axel, but you should of heard that happen while driving.

I guess the logical thing to do is to jack the front end up and try to put it in 4x4 and see if the driveshaft turns. If it does and the wheels don't then it's an axle problem, if not it's a t-case problem

[rwenzek94]

around where are the vaccum lines going too and from?

[Natureboy]

If your truck is like my 87 MM 4x4 there won't be any vacuum lines involved with your front axle or transfer case-it's all mechanical with auto locking front hubs. Not sure what system Bradmph is referring to but unless your vehicle is equipped with some sort of "shift on the fly" 4x4 system you don't have any vacuum lines involved. The first thing I would check is the snap rings in the front hubs that secure the splined shaft in the hub-if it's missing the shaft can pull out and it won't engage. If the shifter feels normal, then something else is happening, but more details would be needed. If you can put the front axles up on jack stands, with the engine off and the transmission in gear, shift the transfer case into 4 hi. Turn one of the wheels manually forward and it should lock the hub, and stop turning. If you need to, you can remove the transfer case separately from the transmission to check it out.

[rwenzek94]

im pretty sure my hub is blown. when i put the transfer case is 4 low the front axles spin but the wheels wont. i took them apart and it the spring is real weak, so im thinkin just to get the manual hubs

[Natureboy]

Glad you figured it out. Hope you find manuals soon!

[Acuta73]

These guys have manual hubs for a reasonable price:

http://www.tuffpans.com/

Finding them in the aftermarket is tough, and a lot more expensive.

[BradMph]

Sorry for misguided missle, I got confused with another 4x4 that had issues like yours. Natureboy is correct, I was wrong...no vaccum lines

[PowerRam348]

manual hubs can be located at knechts auto parts stores. that is where i got mine. i think mine were $189 for the warn conversion. rocky ridge also makes manual hubs for our trucks that are a direct bolt on and can also be sourced at knechts.

[eatdeer1]

I just installed s 3 " lift kit on my 88 MM. Before that I had to put new roters and brakes on it. Repackec with grease all back together. After installing lift kit my shifters did not have enough room to shift into gear and 4x4 did not have enough room to be put in 2 hi. I took shifters off and was very careful then welded in 3" cold rolled steel 1/2 inch round extenders. Got all back together it still will got shift from 4hi back down into 2 hi. Any ideas thanks