Transfer case jumping out of gear. (1 Viewer)

[Torx]

My first proper post so apologies if I’m not following any protocols.

I have a full service history ‘94 U.K. spec LC80 Amazon with the 1HDT 12v diesel and auto box. I’ve owned it for 13yrs or so and bar usual wear and tear it’s been perfect. Baselined with crank bearings, front axle rebuild, shocks/springs, oils etc. Recently though the TC has started jumping out gear and into neutral with a loud bang when under slight power with of course total loss of drive to all wheels of the vehicle. All diffs are unlocked and it’s in road trim. No big mods and only 285/75 AT rubber on OE wheels. When held in gear in the cab by hand there’s no nasty noises from the TC in any of the positions (H, N, L). And the correct lights come up on the dash when in low ratio (cdl engaged). And extinguish when moving back to High.

This happens both in low and high range and on both tarmac and grass/mud so I don’t think trans wind up is the culprit. Also happens without warning when in a straight line (happened on the motorway twice whilst at 55mph climbing an incline). Now just happens all the time when pulling away at junctions/roundabouts.

Firstly thought the engine mounts were shot allowing too much motor twist when under load but I’ve just changed all 3 engine mounts for new and no change. The TC lever moves smoothly and engages in the gear (obvs stationary as its non synchro) and you can feel the detent ball/spring resistance too (which has been consistent since first day of ownership). No sign of excessive resistance to the lever (rubber boot issue considered).

The TC is non-synchro and does not have the viscous coupling on the tail. I think it’s the 2HA version.

Before I get the TC out does anyone have any ideas as to the problem? All reports say they’re bomb proof and why after 13years is it unhappy now? Many thanks you lovely people.

 

[Shipwreck]

I would start with the easy stuff first. Adjust the length of the transfer case shift rod. There is a bushing at one end and a ball joint at he other end. These can both wear over time. The length of the rod can be adjusted to make sure you have proper engagement of the shift fork. If that doesn't help, then you need to delve deeper. There's other bushing and insulators on the shifter assembly, springs for the detent balls, or it could be a transmission shift issue.
But, I would start with the transfer case linkage first.

 

[Torx]

I would start with the easy stuff first. Adjust the length of the transfer case shift rod. There is a bushing at one end and a ball joint at he other end. These can both wear over time. The length of the rod can be adjusted to make sure you have proper engagement of the shift fork. If that doesn't help, then you need to delve deeper. There's other bushing and insulators on the shifter assembly, springs for the detent balls, or it could be a transmission shift issue.
But, I would start with the transfer case linkage first.

Will do, many thanks for your thoughts. Maybe the bushes then. Maybe worn out. The auto box goes through the gears like silk and always has so I don’t think the box has any issues swapping cogs. It’s never refused to change, holds gear happily and kickdown response is great. The ATF is always a perfect red colour.

 

[BILT4ME]

Will do, many thanks for your thoughts. Maybe the bushes then. Maybe worn out. The auto box goes through the gears like silk and always has so I don’t think the box has any issues swapping cogs. It’s never refused to change, holds gear happily and kickdown response is great. The ATF is always a perfect red colour.

Does the lever in the cab move left/right, up/down, or side to side?
This lever has a barrel type support with an arm that connects linkage. If the lever is unsupported, it's possible that body roll / torque is allowing it to disengage. If all correct, there is very little movement, like less than 1/8" in any direction unless shifting gears.

If it's doing it from both low range and high range to neutral, I would guess it is due to slop in the linkage and it is not getting fully engaged in either direction.

Otherwise, do you have stuff (notebooks, parts, gear) laying on the center console that is contacting the lever during operation? I stopped to help a woman in a mid 1980's chevy pickup that couldn't pull away from an intersection. A box had slid forward and pushed her 4WD lever into neutral.

My 96 LC (4.5L / A343) had got to the point that the lever was unmovable, particularly in cold weather. I had to remove all of it, spray with penetrating oil and brake cleaner to loosen it enough to come apart so I could properly clean it. Cleaned and lubed, it's now a two finger movement even at -5°F.

It is possible the shaft itself is "bound up" and the bolts on top of the transmission holding the lever in place are loose and you are moving the entire assembly so it's never really engaging internally. You'll need to remove the center console, shifter levers, and all that to access from the top, then remove the safety pins from the linkages below to get the lever and support out of the truck. It took me about 4 hours to R/R. Well worth the time to figure out the proper solution.

 

[Torx]

Thanks for your thoughts, most appreciated.

The body isn’t lifted and on oe mounts and seems solid (no discernible change in the 13yrs I’ve had the lc). No trash on the console, plus had the console off to reveal the rubber gaiter so all clean and tidy.

The H/L lever feels totally normal and free when engaging low or high ratio, you can feel the detent ball /spring too so that’s the only resistance felt which is expected. It’s pretty short throw anyway.

I agree that it seems the selector fork isn’t shoving the gears far enough to engage properly so when torque is applied they just unmesh with a bang but it seems odd for it to happen in both directions of the h/L lever travel.

I like your suggestion that the h/L shifter assy is loose on the case which presumably means that the h/L lever assy is mounted to the auto box?

Thanks for your thoughts chaps. It’s giving me a direction of travel to explore first as don’t want to get the tc out for no reason.

It’s been a bit chilly here in the last few days (-3deg C) so don’t fancy bruising me knuckles again (did enough of that swapping engine mounts out last week) but will get back under asap and report on what I find.

 

[BILT4ME]

Thanks for your thoughts, most appreciated.

The body isn’t lifted and on oe mounts and seems solid (no discernible change in the 13yrs I’ve had the lc). No trash on the console, plus had the console off to reveal the rubber gaiter so all clean and tidy.

The H/L lever feels totally normal and free when engaging low or high ratio, you can feel the detent ball /spring too so that’s the only resistance felt which is expected. It’s pretty short throw anyway.

I agree that it seems the selector fork isn’t shoving the gears far enough to engage properly so when torque is applied they just unmesh with a bang but it seems odd for it to happen in both directions of the h/L lever travel.

I like your suggestion that the h/L shifter assy is loose on the case which presumably means that the h/L lever assy is mounted to the auto box?

Thanks for your thoughts chaps. It’s giving me a direction of travel to explore first as don’t want to get the tc out for no reason.

It’s been a bit chilly here in the last few days (-3deg C) so don’t fancy bruising me knuckles again (did enough of that swapping engine mounts out last week) but will get back under asap and report on what I find.

Yes, it's bolted to the top of the auto box. Then linkages accessible from underneath (take a pic before you pull the pin because it will scatter the washers and bushings all over)

The 4 bolts that hold it to the top of the auto box are accessible from the top inside the cab.

 

[Fj80oregon]

You can reach up from the bottom of the truck and reach to the top of the transmission to see if they are loose pretty tight fit but achievable.

 

[Torx]

Thanks for your thoughts, most appreciated.

The body isn’t lifted and on oe mounts and seems solid (no discernible change in the 13yrs I’ve had the lc). No trash on the console, plus had the console off to reveal the rubber gaiter so all clean and tidy.

The H/L lever feels totally normal and free when engaging low or high ratio, you can feel the detent ball /spring too so that’s the only resistance felt which is expected. It’s pretty short throw anyway.

I agree that it seems the selector fork isn’t shoving the gears far enough to engage properly so when torque is applied they just unmesh with a bang but it seems odd for it to happen in both directions of the h/L lever travel.

I like your suggestion that the h/L shifter assy is loose on the case which presumably means that the h/L lever assy is mounted to the auto box?

Thanks for your thoughts chaps. It’s giving me a direction of travel to explore first as don’t want to get the tc out for no reason.

It’s been a bit chilly here in the last few days (-3deg C) so don’t fancy bruising me knuckles again (did enough of that swapping engine mounts out last week) but will get back under asap and report on what I find.

So, still not resolved this problem. Jumps violently out of H and L when slowly driving in either forward or reverse. Tried on gravel to eliminate any windup. Have. checked linkages. There’s adjustment available on the trans lever but nothing on the tc case. Lever moves same amount of throw like it always has, virtually zero side to side. Got underneath to trace linkage and can’t see or feel anything loose or out of whack. I’m sadly going to have to drop the tc to find out what’s occurring. Proper pita.

 

[Shipwreck]

There’s adjustment available on the trans lever but nothing on the tc case.

The transfer case shift rod is adjustable. It may not be readily apparent by just looking at it.
Before you remove and tear into the TC, I would at least try to lengthen the shift rod. After 30 years of service, you should expect wear of the shift bushings, shifter rod end, and perhaps shift forks within the TC. Toyota made that rod adjustable so that you can adjust for this wear. It would be very difficult to notice any wear just by visual inspection or by wiggling things by hand. Just a couple millimeters can make all the difference.
Let me see if I can walk you through this:
The shifter rod has a simple plastic bushing on one end and a ball joint (tie rod end) on the other. The rod itself is threaded into the ball joint. The rod length is adjusted by increasing or decreasing the number of threads screwed into that ball joint. Once adjusted, a nut is tightened to secure it from moving.
To adjust, first remove a small pin that holds the plastic bushing end of the rod. Slide the end of the rod off the shifter lever. That plastic bushing on the end is probably worn (or missing) so plan on replacing it. Next, loosen the small lock nut next to the ball joint on the other end of the rod. Now you can spin the rod anti-clockwise to lengthen the rod. You won't need much. Just enough to get the shift forks to fully engage. You may need to try this a couple times to get it right.

You can choose to replace that ball joint if you really want to be thorough. That would require that you remove the rod completely to replace.

This is all doable by reaching up above the transfer case. It is a tight fit, and a bit awkward if you have big hands, but you don't need to drop the transfer case to accomplish this. I once had to do it in the dirt, driving up out of the Rubicon trail when I had symptoms just as you've described.

I would also follow the advice given by @BILT4ME to replace the bushings for the shift plate and lever. Just a little bit of wear in any part of the shift system can be enough to prevent the shift forks from engaging fully. Only after fully overhauling the shifter linkages would I consider removing and rebuilding the transfer case itself.

 

[Torx]

The transfer case shift rod is adjustable. It may not be readily apparent by just looking at it.
Before you remove and tear into the TC, I would at least try to lengthen the shift rod. After 30 years of service, you should expect wear of the shift bushings, shifter rod end, and perhaps shift forks within the TC. Toyota made that rod adjustable so that you can adjust for this wear. It would be very difficult to notice any wear just by visual inspection or by wiggling things by hand. Just a couple millimeters can make all the difference.
Let me see if I can walk you through this:
The shifter rod has a simple plastic bushing on one end and a ball joint (tie rod end) on the other. The rod itself is threaded into the ball joint. The rod length is adjusted by increasing or decreasing the number of threads screwed into that ball joint. Once adjusted, a nut is tightened to secure it from moving.
To adjust, first remove a small pin that holds the plastic bushing end of the rod. Slide the end of the rod off the shifter lever. That plastic bushing on the end is probably worn (or missing) so plan on replacing it. Next, loosen the small lock nut next to the ball joint on the other end of the rod. Now you can spin the rod anti-clockwise to lengthen the rod. You won't need much. Just enough to get the shift forks to fully engage. You may need to try this a couple times to get it right.

View attachment 3850460
You can choose to replace that ball joint if you really want to be thorough. That would require that you remove the rod completely to replace.

View attachment 3850462
This is all doable by reaching up above the transfer case. It is a tight fit, and a bit awkward if you have big hands, but you don't need to drop the transfer case to accomplish this. I once had to do it in the dirt, driving up out of the Rubicon trail when I had symptoms just as you've described.

I would also follow the advice given by @BILT4ME to replace the bushings for the shift plate and lever. Just a little bit of wear in any part of the shift system can be enough to prevent the shift forks from engaging fully. Only after fully overhauling the shifter linkages would I consider removing and rebuilding the transfer case itself.

Hey Shipwreck, you sir are a genius. Your post is exactly what I needed. I’m indebted to you. Thank you. I was hoping and hoping there maybe a way to rectify before having to remove the tc. Everything I’ve read about the TC told me that it’s virtually indestructible so it seemed highly unlikely it was the culprit yet crawling about under the truck yesterday gave me little hope that it might be a rod/linkage adjustment as I couldn’t see anyway it could be adjusted. I’m 6’3” with xxxl hands so that prob made it difficult to see any adjustment. I can’t get my hands above the tc case (between the top of the tc and the body trans tunnel), it’s just too close and too much wiring. You mention the ‘ball joint’ and I can identify it by fingertip feel but there’s no way I can get my hands on it let alone a tool to undo the lock nut (no 3 in your notes). Maybe I drop the transmission cross member and or rear trans mount down to get clearance? Shame Mr T didn’t provide an access cover from inside the cab. You mention the ‘shift lever plate’, presumably thats in the cab end, not the tc case? I’ve also got the centre console out and rubber gaiter off to reveal the second gaiter but no obvious restriction caused by the rubber it seems and the actual lever action is as tight as a ducks arse, no slop or side to side play which is good. The action is very positive and I can easily feel the detent ball resistance when moving from H to L. But as you say, after 30 yrs it won’t take much linkage /bush wear for the h or L not to engage properly/fully.

Thanks for the step by step, you’re super kind to provide that. Sunny (but frosty) today so will get under and have a go.

 

[Shipwreck]

Yes, you can loosen the transmission crossmember and lower the TC a few cm to gain more access. I would also slightly loosen the motor mounts to allow the drivetrain to angle downward easily. Just keep an eye on heater hoses and radiator fan when you lower the rear.
You would need to undo the shift linkage even if you decide to remove the TC.

 

[Torx]

Update on the TC problem:
It’s just too difficult to get to the adjustable end of the tc shift rod assy from underneath and getting a 12mm spanner on the locknut is virtually impossible as access is extremely limited due to the centre diff lock mech and trans tunnel however there is a much easier route… just remove the passenger seat, console covers and shift lever plates and you can get easy access from above. I used a crows claw spanner to loosen the locknut (as its under the trans tunnel on the far end of the rod) and adjusted the linkage as Shipwreck kindly described. The bushing on the lever was in perfect condition. The H/L shift lever yoke looks great and was securely bolted to the top of the trans (it does not have a gate or detent it’s simply a fire/aft lever) so the only restriction is can suffer is either trapped rubber gaiters or it hitting its own yoke mount but all was good. All in amazing condition for 30 yrs old!

Sadly after making this adjustment and driving the truck on loose gravel the tc still snaps out of gear at the slightest provocation off engine idle. Both in h & L, forward & reverse.

So i don’t think it’s lever or rod adjustment nor the ball joint end into the tc (as it’s free of slop too).

When selecting h or L the tc cleanly selects the ratio and I can feel the detent ball & spring resistance nicely but as soon as torque is applied above engin idle it jumps out of gear.

Sadly I think the next move will be to get the tc out.

 

[Torx]

Update: we’ve now got around to getting the TC case out. A bit fiddly but managed to locate all the 6 bolts that hold it to the gearbox and overall pretty easy to do. Cracked open the TC case and with the help of a transmission tech and his tools we removed the innards and discovered bad wear on the dog teeth that locks the gear set to high ratio. The actual driven gears are all perfect it’s the hub and associated gear that locks in the H or L selection. But the horror really is the cost of the parts which amazingly are all available from Mr T. The selector hub is only £116 plus vat but it’s the actual high speed gear unit that’s frightening, it’s £1028! Any suggestions?