Topic: T-Case Shifting Problem? (HELP!!!)

[79-83earlyota]

Let me give you a quick background of what's up, before I get to the root of the problem.  (I currently have a 1985 X-Cab EFI truck used mostly for off-road. I've owned about two dozen of the solid-axle era trucks, and out of that number, have probably welded the rear diff on on least half of those. So, since having done it so many times before without any problems, I deceided to weld the rear diff on my 85 I have now too.)

Ok....that brings me to the main problem. Ever since welding the rear differential, when taking the truck off-road, it shifts in to 4WD just fine, but when it comes to getting it back in to 2WD, it's nearly impossible!!!  What is up with that??? I have tried all the old tricks of unlocking the hubs first...stopping and backing up about 10 feet, etc., etc....nothing seems to work!?  The T-Case worked and shifted flawlessly before welding the rear diff.  It took about 30 minutes the other night of pulling forward and backing up, shifting between 4hi and 4low, before it FINALLY shifted back into 2WD with a fairly loud thud.  

As I mentioned above, I have run about a dozen old Toyota's with gear-driven top-shift t-cases while running a welded rear diff, and never had this problem, so I don't know what to think!? Also as I said, the t-case worked flawlessly before welding the rear...so many might be inclined to say just replace the 3rd with a Detroit, or it's welded wrong, but the truck drives great in 2WD and 4WD whether on the highway or off-road.  It just seems the welded diff is having some strange effect on the t-cases ability to shift???  I am really puzzled on this one, so any help would be greatly appreciated!  

[fade]

Could be the case slowly taking a dump. Have you checked the fluid?

[79-83earlyota [OP]]

Could be the case slowly taking a dump. Have you checked the fluid?

Actually changed the fluid with 80W90 a few months back, so the fluid is new and full.
The old fluid that came out of the case was amber, and not burnt, nothing unusual there.

I have a 4.7 case ready to bolt in to this truck but I am afraid to install it and have the
same issue, or worse, cause damage to the new case. I would like to find out more, or
hear from others out there that may have experienced a similar problem.

more opinions/help please...........

[superyota]

I have a similar issure with mine, but I've never wrestled with it for that long.  usually roll it back a forth a few times with the hubs unlocked, and pop, it comes out.  i do have to put a little muscle into the shifter though sometimes, and it does make a really loud "pop" when it comes out, but its never been bad enough to make me worry about it.  not sure if that helps, but thats the only experience i have with anything like that.

[79-83earlyota [OP]]

I have a similar issure with mine, but I've never wrestled with it for that long.  usually roll it back a forth a few times with the hubs unlocked, and pop, it comes out.  i do have to put a little muscle into the shifter though sometimes, and it does make a really loud "pop" when it comes out, but its never been bad enough to make me worry about it.  not sure if that helps, but thats the only experience i have with anything like that.

Yeah, that's what mine is doing alright...like you said, not sure why it's taking so long for it to finally pop back into 2WD???  The ironic part of all of this, is that it never had this problem before I installed the welded diff.  But yet the truck drives fine with it in there.  It almost as if the torque or added pressure from the locker is jamming the shift rails somehow?

 

[superyota]

Yea, thats kinda what i figured.  with the front and rear not working together when they are welded, spooled, etc, the fron and rear fight eachother.  tcase seems to get into a bind is what it feels like to me.  but mine has been doing it for about 4 years now, and never had any problems with it besides it being hard to take out.  i wouldn't worry about it.

[superyota]

oh yea, one way i got mine to come out easier, while its rolling, try to pull it out.  i've even cruised mine in 1st gear(cruise, no pressure on the drivetrain), and taken it out that way to.  makes it a bit easier.

[79-83earlyota [OP]]

oh yea, one way i got mine to come out easier, while its rolling, try to pull it out.  i've even cruised mine in 1st gear(cruise, no pressure on the drivetrain), and taken it out that way to.  makes it a bit easier.

so basically in other words while it's rolling in neutral, or cruising (foot off the gas in first gear),
push the shifter from 4hi to 2hi? You would think that would help, you're right.  Seems I tried
that too though, during my half-hour wrestling match trying to get the #$%*#@ thing back in 2WD, LOL!
I don't know why it's being such a

[superyota]

yes, but foot not off the gas because then you have the pressure of the drivetrain slowing down.  you should be on the pedal just enough so there is no pressure on it trying to speed it up, or slow it down.  hope that makes sense.

[79-83earlyota [OP]]

yes, but foot not off the gas because then you have the pressure of the drivetrain slowing down.  you should be on the pedal just enough so there is no pressure on it trying to speed it up, or slow it down.  hope that makes sense.

that does make sense...thanks superyota...all your help and suggestions are very much appreciated!!!
I will give that a try, it can't hurt at this point.  I would think making sure the hubs are unlocked when going from 4WD to 2WD would always help and not hurt too!? 

Any other input...............

[79-83earlyota [OP]]

Yea, thats kinda what i figured.  with the front and rear not working together when they are welded, spooled, etc, the front and rear fight each other.  tcase seems to get into a bind is what it feels like to me.  but mine has been doing it for about 4 years now, and never had any problems with it besides it being hard to take out.  i wouldn't worry about it.

that seems to make a lot of sense.  I wondered about this particular issue when I was on
a stretch of level, fairly smooth, dirt road in 4hi...and the truck started to have some "interesting"
steering.  Almost as if the front and rear diff's were fighting against each other.  The rear getting
all the traction and pushing the truck, and the open front kinda slipping and pulling side to side.  Again, this
is all new to me as none of my trucks in the past acted this way with a welded diff.

[79coyotefrg]

ok guys,  assuming you have the same gears in front and rear you have to make sure the front tires and back tires are at the same height.
I usually run 15 pound in front and 10 in the rear, unless i'm hauling firewood or camping gearthen its whatever get the tires closest.   how to do this??   park on a FLAT surface,  measure the front wheel from the ground to the wheel. on a 35 at 30 psi  your looking at close to 10 inches ground to wheel.  when you air down for the trail  just match front and back.  this will keep your gears from binding up.
NEVER FORCE THEM out or in to gear you can bend the forks causing permanent damage

Also,  i never unlock my hubs till i'm in 2wd.  its much easier to get the tcase out of gear  by having both sides turning when you back up.   if its binding when going forward the only way to get it to unbind is either loose dirt or gravel OR to simply back up till it comes out,  doesnt matter if its 10 feet or 100 feet.

[superyota]

good point glen.  i'll give it a shot next time i'm out

[79-83earlyota [OP]]

ok guys,  assuming you have the same gears in front and rear you have to make sure the front tires and back tires are at the same height.
I usually run 15 pound in front and 10 in the rear, unless i'm hauling firewood or camping gearthen its whatever get the tires closest.   how to do this??   park on a FLAT surface,  measure the front wheel from the ground to the wheel. on a 35 at 30 psi  your looking at close to 10 inches ground to wheel.  when you air down for the trail  just match front and back.  this will keep your gears from binding up.
NEVER FORCE THEM out or in to gear you can bend the forks causing permanent damage

Also,  i never unlock my hubs till i'm in 2wd.  its much easier to get the tcase out of gear  by having both sides turning when you back up.   if its binding when going forward the only way to get it to unbind is either loose dirt or gravel OR to simply back up till it comes out,  doesnt matter if its 10 feet or 100 feet.

Thanks for the input, much appreciated

[79-83earlyota [OP]]

UPDATE: Well, the t-case was still shifting weird with the welded diff in it, even after trying all the suggestions. I work as a welder at a mechanic shop, so I put my truck on the hoist, and with all the tires off the ground and no pressure on them, I ran the truck with the hubs locked in 4low and went through 1st, 2nd and 3rd gear.  Then stopped, and it shifted right back into 2WD like butter.  So........it seems nothing is wrong with the t-case at all.  I guess the welded diff is causing something at this point!?  I tried putting equal amounts of air pressure in the tires and that didn't do much either.  At this point i'm about out of patience, and might just put a Detroit in the rear and see what happens.  The mechanics I work with have given about all the suggestions they can, and so have the dudes on this board, and are probably sick of this stupid thread anyway, so I guess I will pull the welded diff and move on with life..... 

Thanks to all those who helped!! 

[crabcrawler]

i have detroits in both ends and mine is doing the same thing, i end up removing the shifter and manually moving the shift rails, im at a loss.