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I think superbuickguy runs an ax15 in his V8 FJ40. He has a thread in the hard-core section. Shipwreck

I have friend that has a yj with one. We squeezed a doubler behind it. AX15, a shortened np231, and a flipped dana 300. We had to move the dana 44 rear back 3", because of the added Tcase. The ax15 shifts and drives nice. 1st gear is close to the same ratio as the H42, with about a 20% reduction in 5th. They are certainly affordable compared to other 5 speeds and fairly robust. Stay away from ax5's
 
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I briefly had a SOA YJ with the AX15, and beat the living bajessus out of it like it was stolen

AX15 took it like a champ and zero issues.

Tranny was about the only thing I liked about that pile

Oh the Lincoln locker days….
 
badsamaritan said:
I'm not against the ax15 after looking at prices and comparing with other options. If you don't mind I'd like to ask PM you some questions. My understanding was they are really long case wise and that created issues.
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Yeah, let me know any questions you have. It's long but really not bad. My rear driveshaft is probably a good 2 feet long so zero issues. LC has about the same wheelbase as a YJ so its not a particularly tight fit.

Couple interesting notes on the AX15:
- Its still in production. You can pick up a brand new one if you wanted and parts are easy to come by.
- While generally used in Jeeps, its an Aisin tranny directly related to the Toyota R series used in everything from pickups to Supras. So not 100% out of place in a LC.
- Lots of aftermarket support and adapters available. Was super simple to hook up to my SBC.
 
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lots of updates over the last couple of months.

1. completed the dash upgrade - all new gauges, cleaned up the gauge panel wiring, removed the weird switch panel that I didn't like.
2. started digging into clutch issues, and have found some carnage:
  • Clutch fork pivot ball threads were stripped and the ball fell onto the floor.
  • Clutch fork return spring was missing
  • T.O. Bearing was shot
  • Flywheel scorched a bit (Clutch disc not releasing fully?)
  • Input shaft bearing wallowed out and damaged.
 
This is where the ugly Painless switch panel was:

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I had a friend make a 2d model of the panel in TinkerCAD and I sent that to SendCutSend and they made me a panel out of aluminum. I added the wiper switch to (so I wouldnt have to add another hole to the dash) and a RAM Ball mount for a cell phone holder

PXL_20251206_183735363.webp
 
Moving on to the clutch, since the pivot ball was stripped, I decided to swap bell housings. It looks like I have a pre-1955 Bellhousing that has the pivot ball threads cast into the bell vs. having the big removable plug that most bells have now.

Old Bell on the right, $100 Ebay Bell on the Left. Both bells look to have the same casting number
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SM420 dropped shows a pretty rusty pressure plate and disc, nothing super obvious yet.

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Clutch removed shows pretty rough flywheel
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Lots of damage to the pilot bushing, the ID was way wallowed out, and the OD had lots of damage as well. Need to call AA and see if they can tell what went wrong here and help me order some new parts. Also noticed the LH side alignment dowel in the block is missing.

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I would guess the missing dowel contributed to the pilot bushing wear. I've been running a similar setup for decades with no issues.
 
pb4ugo said:
I would guess the missing dowel contributed to the pilot bushing wear. I've been running a similar setup for decades with no issues.
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There was one other possible smoking gun....when I first bought the truck back 3 years ago, I noticed the bellhousing frame mounts were present but there were no bolts from the bellhousing into the mount. The bell was just sitting on them. I fixed that right away, but who knows how long it had been bouncing around unsecured like that.
 
I dont use any mounts on the b/h. My tcase is non stock and i run a crossmember under the tcase adapter. Any trans misalignment is going to take out the pilot bushing and sometimes can make shifting difficult. Are you running a propeller crossmember on the bsck of the 40 tcase?
 
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pb4ugo said:
I dont use any mounts on the b/h. My tcase is non stock and i run a crossmember under the tcase adapter. Any trans misalignment is going to take out the pilot bushing and sometimes can make shifting difficult. Are you running a propeller crossmember on the bsck of the 40 tcase?
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I'm not but have been considering it. I am still using the stock Tcase for now. The main reason I haven't added one is that I really want to go to a different transmission which may force a new tcase as well. I was pretty close to having the funds stashed for it until some recent life events. Now I'll be happy to just get it back on the road.
 
Update from the last few days:

Used the old bread trick to remove the old pilot bushing

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I ordered a new complete kit from AA ( PN 712500M) with new flywheel, clutch, pilot bushing, throwout bearing, and bolts. I Pressed the pilot bushing into the adapter after calling them to make sure I had everything orientated correctly.

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Tapped it into the crank and installed the new flywheel:

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Hopefully I will get some more time to get the clutch installed and the new to me bellhousing installed.
 
@Boston Mangler came over today after cars and coffee and we got to work on installing the trans and tcase. Definitely wasn't an easy install, but after making some dowels for the trans to bell bolts we were able to get it mostly installed.

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There's still a bit of a uneven gap on the trans that I don't like. I'll need to try some things there before its all done. Drivers side top bolt and passenger side lower seem to have the biggest gaps.

Drivers side top:

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Passenger side top, I would say the underside gap is probably close to 1/16th of an inch

PXL_20260119_002503793.webp
 
That should be fine. The input shaft is in the pilot bearing. You could push in the clutch if you're overly concerned.
 
pb4ugo said:
That should be fine. The input shaft is in the pilot bearing. You could push in the clutch if you're overly concerned.
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My main concern is from the bottom the throw out bearing looked slightly cocked to one side. But I just glanced at it. I was pretty tired after wrestling with it. I'll grab some pictures maybe this evening.
 
The T/O bearing slides on the trans bearing retainer collar and has nothing to do with the alignment of the trans input shaft to the flywheel pilot bearing/bushing.

Edited for clarity.
 
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pb4ugo said:
The T/O bearing slides on the trans bearing retainer collar and has nothing to do with the alignment of the trans input shaft to the flywheel.

Edited for clarity.
Click to expand...

I understand, but if the trans is slightly cocked to one side and not flush with the bell (creating a slight gap) wouldn't that also mean the throw out bearing could be slightly shifted to one side as well?
 
The trans is mounted flush to the bellhousing so it's parallel to the engine, the trans is centered in the bellhousing by the bearing retainer and the bellhousing opening, the trans input shaft is centered to the crankshaft by the pilot bearing/bushing. The bellhousing is center to the engine by dowel pins.
 
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