2nd Gen Non-Engine/Transmission 4x4/Transfer case destroyed?

[snowracer69]

Buddies pickup, same year and BOMBs as the one in the signature, but he does have billet input shaft/hub in his transmission, therefore he's been launching in 4x4... anyway, there's a major problem...



Now, when he try's to pull it in 4x4, the transfer case makes a terrible grinding noise... it does go in, but takes a while... this is from a dead stop. If he's rolling about 15 MPH and pulls it in, it goes in fine, and that is where the real problem starts...



once it's in 4x4, if he gives it any real throttle (half or above) it yanks to the right something fierce!!! It pulls all over the road and it's very difficult to keep straight... this makes for some very interesting 4x4/20 PSI boost launches.



What could be the problem, and how can we fix it? Thinking new transfer case, but why would that cause it to pull right so hard? Is it possible to weld a hub or something like that?



thanks, Josh

 

[Extreme1]

What condition are the front axle u-joints in? The pull to one side shouldn't be cause by the t-case.



The grind, however, is. When you engage 4x4 at any speed, the synchro (looks just like a manual trans synchro) has to spin everything up to speed before the lever will engage completely and send the vacuum signal to the front axle.



On a manual trans, it spins up the clutch disk, input shaft and countershaft to match the gear ratio speed (depends on which gear you're in) of the output shaft. That's not too bad.



On these truck, however, when you pull the t-case lever, you start to spin the following parts (all are at rest except for the rt. axle which is spinning the correct speed - backwards): The t-case chain drive sprocket, driven sprocket (these are really big and very heavy), chain, driveshaft, front axle carrier assembly and the rt driveshaft. Lots of mass!



If your friend used 4x4 a lot and engaged it at speeds above 15 a lot, the synchro might just be worn out. But then it should make noise at 15 mph and be silent when engaged at 0 mph.



When he shifts it into 4x4 is the trans in gear?



How does the t-case lube look?

 

[ToolManTimTaylor]

Originally posted by snowracer69

it yanks to the right something fierce!!! It pulls all over the road and it's very difficult to keep straight

I would start to look at the front axle disconnect. It sounds like there is something hanging the vaccuum unit half way. Check the lines for cracks or an air leak.

 

[rubberneck]

what about a broken motor mount??

 

[ToolManTimTaylor]

What I was tryin to say is much easier now. Take a closer look at the shift collar as it engages from left to right. Ive seen a few where the collar overextends and just simply moves the collar from the right shaft to the left. Also theh collar may be stripped on the right hand side from torque shear and only the left axle turns when 4X4 is engaged.



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[Hogan]

Keep in mind that unless there is an LSD or locker in the front axle there will be no power going to either side of the axle should one of the shafts or u-joints break.



If he has a locker (Detroit, ARB, etc) in the front axle and one of the axle shafts breaks or the vacuum switch doesn't engage, there will be mass amounts of torque steer since only one side is getting power.



Something busted and no traction aid then no power. All a differential does is split torque equally to both sides. The amount of torque is determined by the side of the diff with the least resistance. This means that if a shaft is broken or a tire is in the air it won't take much torque to spin the shaft, say 25lb/ft. The solid side that's not broken or is on the ground also only gets 25lb/ft of torque, which if that is the only drive tire with contact you won't be going anywhere.

 

[Extreme1]

Hogan is right, no torque transfer with broken axle or not engaged axle disconnect. The only thing that I could think of is a very worn u-joint that might get bound up if there was enough movement possible to cause misalignment.



How about worn steering parts?