Transfer case kicking me out of 4lo

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Mar 4, 2024
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Location
oregon
Fairly recently installed a part time kit, gear reduction and rear locker. Pretty much all at the same time. It's started kicking me out of 4lo, specifically under load. Is this a backlash issue with the locker (spartan) locking, mis-aligned linkage or what? I can hold down the shifter in 4lo to keep it from popping out, but it's pretty obnoxious trying to navigate anything you'd need to be in 4lo for without two hands on the wheel. Just wondering if anybody can point me in a direction to be looking for issues.
91 fj80 Hf2a xfer case.
 
On my 60 series I had this issue; while wear of the transfer was considerable at the time, the primary solution was adjustment of the transfer shifter.
 
On my 60 series I had this issue; while wear of the transfer was considerable at the time, the primary solution was adjustment of the transfer shifter.
Ok, is that an adjustment at the shifter itself or the linkage closer to the tcase? I think I remember the linkage just going on one way at the tcase, but I'll double check that
 
It was a couple decades ago+ (I forget). Cleaning and regreasing the linkage helped. My memory is that the linkage pivot was quite worn and was replaced.

The pic below should be your transfer linkage for a 91 FJ80. Check for play in the linkage. Cleaning and regreasing the linkage joints/pivot would probably help as well.

Here are some hints:

1729633047724.png
 
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This pic from this link may help:



1729634594198.png
 
It was a couple decades ago+ (I forget). Cleaning and regreasing the linkage helped. My memory is that the linkage pivot was quite worn and was replaced.

The pic below should be your transfer linkage for a 91 FJ80. Check for play in the linkage. Cleaning and regreasing the linkage joints/pivot would probably help as well.

Here are some hints:

View attachment 3755721
This is great! Thank you!
 
If this was not an issue before you did the gear swap in the transfer case, then it's most likely an error with the reassembly internal to the case.
The shift Fork mechanism internal to the transfer case has a spring loaded detent ball that is supposed to keep the shift fork in place in all three positions. With the linkage removed, you should be able to easily feel the detents as you move the lever on the case manually. Each position should snap into place.
The shift lever in the cab has far more range forward and backward then the linkage on the transfer case, so it's unlikely to be linkage related unless you have adjusted it while the case was out.
 
If this was not an issue before you did the gear swap in the transfer case, then it's most likely an error with the reassembly internal to the case.
The shift Fork mechanism internal to the transfer case has a spring loaded detent ball that is supposed to keep the shift fork in place in all three positions. With the linkage removed, you should be able to easily feel the detents as you move the lever on the case manually. Each position should snap into place.
The shift lever in the cab has far more range forward and backward then the linkage on the transfer case, so it's unlikely to be linkage related unless you have adjusted it while the case was out.
Huh
If this was not an issue before you did the gear swap in the transfer case, then it's most likely an error with the reassembly internal to the case.
The shift Fork mechanism internal to the transfer case has a spring loaded detent ball that is supposed to keep the shift fork in place in all three positions. With the linkage removed, you should be able to easily feel the detents as you move the lever on the case manually. Each position should snap into place.
The shift lever in the cab has far more range forward and backward then the linkage on the transfer case, so it's unlikely to be linkage related unless you have adjusted it while the case was out.
It indexes into all three. It is strange that theres no way it could be linkage related with gear dimension changed.
 
A linkage adjustment was not necessary when I had low range gears installed on my 93 several years ago. I suppose an adjustment is worth a try prior to going back into the T-case. Did you do the work or did a shop do it?

An 80 series transfer case popping out of gear is very unusual and is the reason internal issues are being pointed to especially following major work.
 
A linkage adjustment was not necessary when I had low range gears installed on my 93 several years ago. I suppose an adjustment is worth a try prior to going back into the T-case. Did you do the work or did a shop do it?

An 80 series transfer case popping out of gear is very unusual and is the reason internal issues are being pointed to especially following major work.
I did the work, well everything but the gear pressing which was done by a Land Cruiser shop. But there's really not much that could go wrong in that case. Shims all went back in, springs, detent balls etc. I'm trying to think of what error is even possible. It's possible that the cdl actuator gear could have been clocked wrong if that's a thing? But even that engages and disengages and shouldn't have an impact, although I'm not entirely sure. I'm not tearing open the case if I don't have to, seems like starting with other items makes more sense. After eliminating everything else I'll end up there eventually if nothing else works.
 
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If this was not an issue before you did the gear swap in the transfer case, then it's most likely an error with the reassembly internal to the case.
The shift Fork mechanism internal to the transfer case has a spring loaded detent ball that is supposed to keep the shift fork in place in all three positions. With the linkage removed, you should be able to easily feel the detents as you move the lever on the case manually. Each position should snap into place.
The shift lever in the cab has far more range forward and backward then the linkage on the transfer case, so it's unlikely to be linkage related unless you have adjusted it while the case was out.
I guess I should have stated that this was a heavily modded Land Cruiser when I got it, so I'm not exactly sure if the linkage had been adjusted. I didn't really get it to a point to take it off road before my "fixes"
 
Huh
It indexes into all three. It is strange that theres no way it could be linkage related with gear dimension changed.
The only thing that changes with a gear swap is the circumference of the individual gears. The gear stack still sits on the exact same pivot point. The sliding coller that the shift fork moves is in the exact same place.
If there needed to be an adjustment, then you would need to change the detents of the shift mechanism.

One thing I will add, about 100 years ago on the old 80s Cool forum, there was an artice regarding kicking out of low range due to a body lift or severely worn body mount bushings. The lift prevented the in cab shifter from moving fully throuout it's range and if the body really slops around, it could interfere with the shifter.
 
The only thing that changes with a gear swap is the circumference of the individual gears. The gear stack still sits on the exact same pivot point. The sliding coller that the shift fork moves is in the exact same place.
If there needed to be an adjustment, then you would need to change the detents of the shift mechanism.

One thing I will add, about 100 years ago on the old 80s Cool forum, there was an artice regarding kicking out of low range due to a body lift or severely worn body mount bushings. The lift prevented the in cab shifter from moving fully throuout it's range and if the body really slops around, it could interfere with the shifter.
No body lift, but I think there are definitely some worn body mount bushings. Thank you for that insight.
 
Have you checked that rubber boot under the console? Mine wouldnt let me pull all the way into low when it was cold out, but fine when it was warm. Just a thought.
 
Have you checked that rubber boot under the console? Mine wouldnt let me pull all the way into low when it was cold out, but fine when it was warm. Just a thought.
Took it apart yesterday after work, it indexes perfect into 'lo n hi' It kicks out only when under load, it feels like (and this is pretty anecdotal) when the locker engages it kicks out. So going up a loose muddy climb, it will kick out, it stays in going down a similar hill using gear braking.
It's pretty obnoxious since it's during the times you really want to have two hands on the wheel. I end up holding the xfer case shifter down in lo now. Well I've been out on trails 3 times.
 
The only thing that changes with a gear swap is the circumference of the individual gears. The gear stack still sits on the exact same pivot point. The sliding coller that the shift fork moves is in the exact same place.
If there needed to be an adjustment, then you would need to change the detents of the shift mechanism.

One thing I will add, about 100 years ago on the old 80s Cool forum, there was an artice regarding kicking out of low range due to a body lift or severely worn body mount bushings. The lift prevented the in cab shifter from moving fully throuout it's range and if the body really slops around, it could interfere with the shifter.
So here's a thought. When I bought this it was lifted about 4.5" with no correction on the pinion, matter of fact the pinion was pointing toward the ground, I bought a dc shaft, measured for the length, as well as adjustable upper and lower links. Is it possible that after adjusting the pinion angle with the new driveshaft that a slight bump of the locker engaging is pushing the output shaft just enough to disengage 4lo? I don't know I'm kind is spitballing, but that just occurred to me that the driveshaft could be too long after I corrected the pinion angle and lowered it down to 2"
 
Took it apart yesterday after work, it indexes perfect into 'lo n hi' It kicks out only when under load, it feels like (and this is pretty anecdotal) when the locker engages it kicks out. So going up a loose muddy climb, it will kick out, it stays in going down a similar hill using gear braking.
It's pretty obnoxious since it's during the times you really want to have two hands on the wheel. I end up holding the xfer case shifter down in lo now. Well I've been out on trails 3 times.
Just an opinion, I’ve read through this thread, and I think if your transfer case is functioning normally and the detent is not worn, something is bumping the linkage or preventing it to fully engage. No terrain should cause it to drop out of low normally.
 

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