Offroad-Express

Gidday all,

So after a great weekend at woodhill last weekend, I noticed a crack in my transfer case.... (Thankfully I had a spare one).

So this morning I set about dropping the t-case, splitting and replacing what needed replacing, put it all back together and back on the truck n refilled with fluid. (Its an auto and transfer case from a KZJ78 Landcruiser mated to a lexus v8 in a hilux by the way)

Started it up - put it in gear (It's auto by the way), and drove forward a couple of metres, put it in reverse, and it still want's to drive forward? Put it in Park, still want's to drive forward?!? Switched it off, started it back up, and now doesn't want to drive in any gear at all?

I've checked all the linkages, all good... dropped the drive shafts, and tried again, still no output from the transfer case in any gear?

Before putting the transfer case back in, checked to make sure both front and rear outputs were turning smoothly... and made sure the sleeve between the auto and t-case was sitting in the right place.

I guess i'm going to have to drop the t-case again tomorrow, but its kinda got me scratching my head.... Torque converter packed up? Auto crapped itself?

Cheers,

Jay

If you only played with the transfer case.. it won't cause the fault you are getting re the auto only driving forward..
Are all the linkages to the auto aligned correctly...From the gear lever???
Are they tight !!! So it hasn't been moved to D and then stayed there when you changed to the other gears??
I lost D once and found the linkages were only slightly out (between selections) and I got no drive....

Hey Calvin... That was my first thought too, but all checked and nice and tight and selecting correctly....

I have since had a thought though... when I first started it, after putting it back together, it was quite hard to start (didnt think much of it at the time) and when I selected drive, it felt quite laboured...

Possible that it somehow locked between the auto and t-case, putting stress on the torque converter, until it spat the dummy - hence now not getting any drive?

Jay

So when you did the job how did you do it??
Drop the auto and transfer case together???
Then work on it on the ground?
Or drop transfer case off in the truck from the back of the auto...

Dropped the transfer case off the back of the auto in place...

So I cant see any reason why doing that job would stuff the auto.
Is the fluid level correct???
If the transfer case was jammed up you would have problems rolling the truck around (unless its in N).
I have had mine out a few times and never had that problem...
Unless its just coincidence...

I would take off the PTO cover, drop the rear drive shaft and with the auto in N turn the driveshaft flange and see if it turns freely and back drives ok, you can see the gears turn thru the pto hole...
Then you can rule out any issues with the transfercase...

Yeah me either - I've dropped plenty of transfer cases, and auto's, and never encountered this - hence the head scratcher.

Fluid levels checked in both t-case and auto, and all good... Have also checked the gears through the pto hole as you suggested, and the gears are turning freely in both directions.....

I have a spare auto sitting in the garage too, so if it comes to it, I can change it.... just a pain lol.

Jay

Don't know anything about the auto's but if its not a simple selector issue I would have a guess the "sleeve" between the auto and tcase got hung up during install and has put forward pressure on the output shaft etc . Wonder if that is enough to lock up the gears until something gets spat out ?

Just the way you say it wanted to go forward all the time I definately sounds locked up .

Edit - are you sure the t/cases were the same , ie the input shaft was not longer and that the sleeve engaged it ok ? Sounds like you did .

Good Luck
Chris

Hey Chris,

Yeah.. That's the only thing I can put it it down too? Something locked, causing enough pressure to cause failure somewhere in the auto box... Although i would have thought it would have taken a lot more to overload the torque converter.

T cases were definitely exactly the same, as I've had that one on the truck before.

Jay

Did the transfer case slide all the way up freely or did you have to pull it on with the bolts.

The KZJ78 auto is fully ELectronic so could be that if it was jammed it then caused an electrical issue, maybe the loom got damaged or one of the solenoids is stuffed? I have the manual for it which shows you how to test the solenoids, but my server is offline and buried as we just moved house.

Even if you loose all electrical signals to the auto... It will still go fwd and rev..
as the physical selectors move in the box and change the flow of the fluid... Just don't get all the gears...
Still doesn't explain the fwd movement when in P and Rev !!

Hmmm... That's got me thinking...

Since the initial start up, where it only wanted to go forward, it now doesn't want to select any gear at all..

I have a spare trans sitting here, do I try swap out the solinoids? Or bite the bullet and swap the whole thing over...?
Like Calvin says, even with no electrical input, it should still move forward and back, just not have the full gear range..?

Jay

dont know much about toyotas, but if you put the other trans in it would isolate wether or not its an electrical problem further up would it not?

if the other one ends up working atleast youl have time to diagnose the box and get it sorted, while still having a vehicle.

Yeah, that's my thoughts too at this stage dirtydog..

I've just dropped the t case and it looks good, everything is turning freely as it should, which tells me it's not getting input from the trans. Off it comes

Jay

Hi all,

FYI - all sorted, cheers for your input. Calvin, as suggested, I think the sprag clutch in the auto went.. And pretty sure just coincidental. Added Bonus with the new auto, doesn't bang into gear like it did before!

See y'all at woodhill on the 25th

Cheers,

Jay

Thats good news Jay.... With that banging you had before might have been the sprag clutch playing up....

Cheers Calvin, and yeah, quite possibly!

Jay