Transmission swap issue

Hey guys,

The weekend before last I swapped the AW4 out of my '91 in favor of a '93 AX15. I used the bronze pilot bushing from Novak because my engine originally would have came with a small input shaft AX15 and the '93 is the larger diameter shaft. Brand new Luk clutch, slave cylinder, flywheel, and master cylinder. Everything went together as easy as can be expected.

The problem: I cannot get the clutch to disengage. I've bled the clutch the conventional way, vacuum bled, and ive back bled it. New master cylinder, slave cylinder, and orings in the clutch line. There is no air the system at all, pedal feels like it should. After all this I pulled the starter and checked for proper actuation of the slave cylinder with my bore scope. The slave actuates like it should but the problem is it's not touching the pressure plate. The throwout bearing must be a solid inch away from the pressure plate. I just pulled the transmission again and I cannot tell what is causing the slave to be so far away from the pressure plate.

Do you guys have any idea what could be wrong? I'd appreciate any advice you guys have, I'm at my wit's end.

Did YOU-measure the inside diameter of the bushing and the pilot on the input shaft.

Wayne Sihler said:

Did YOU-measure the inside diameter of the bushing and the pilot on the input shaft.

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I did check the pilot when I first received it. Slid it onto the input shaft as well and it seemed correct. After i pressed the bushing into the end of the crankshaft I do believe that it shrunk the bushing down a bit but I checked the ID of the bushing and the OD of the input shaft and it appeared to be okay.

I do have a new pilot bushing on the way, this one is for a 70's CJ5 with a 304 and T15 which has been used by others for this swap. I suspected that the pilot had possibly shrunk too much because it was a real pain to get it to sit in the pilot bushing, through the splines was easy but it took me probably 4 hours to get the input shaft to sit into the pilot. Maybe it is too tight of a fit? I'm really not accustomed to working on standard transmissions, despite me loving to drive them so I'm learning as I go.

The pilot bearing is not your problem. If the throw out never touched the pressure plate, you need to focus on that. It sounds like you have the wrong flywheel or slave or pressure plate or something. The pilot on keeps the input shaft from wobbling. I've received misboxed clutches before, so it's not unheard of.

trippled said:

The pilot bearing is not your problem. If the throw out never touched the pressure plate, you need to focus on that. It sounds like you have the wrong flywheel or slave or pressure plate or something. The pilot on keeps the input shaft from wobbling. I've received misboxed clutches before, so it's not unheard of.

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This might be a stupid question but how do you tell if the parts are mismatched? The numbers marked on the pressure plate aren't even close to matching the part number for the clutch kit but I'm not sure that it should. I'll compare the original slave to mine tomorrow and see if there are any differences.

Short of comparing it to another part you'd have to get another kit and see.

Why do none of you post pics?


And, if you went to this much trouble, why did not you go with an external slave????

Is the clutch plate itself in the correct position? there is an engine side and a trans side.

Are you sure the transmission you're using is from a 93? Both the internal and external slave models came with the larger tip diameter on the input shaft. You might have an external slave version, which won't work with the internal slave or vice versa. The external slave version of the AX-15 has a different bearing retainer. That could be your problem.

If that's the case, shouldn't the external slave style have a fork pivot in the case somewhere? Could be something to look for in there.

When I installed the friction disk I made sure that the flywheel side faced the flywheel.

I got everything I needed for the swap along with the tranny for a mere $250. An external would've cost me upwards of $1000 without guarantee that it even worked. So that's why internal. With quality parts I shouldnt have problems with the internal slave for a long time.

The part number on the case is 53009528 which is listed as a 92/93 internal slave with a large input shaft. Or at least that what the guy at the Dodge dealership told me. I pulled the transmission from a rig with a build date of 3/93. Also the bell housing doesn't have any holes where the external slave would go, only a rubber piece where the internal slave lines go through.

I can't get pictures to upload right now but I will try tomorrow.

I appreciate all the help guys. This has confused me pretty good.

When I installed the friction disk I made sure that the flywheel side faced the flywheel.

I got everything I needed for the swap along with the tranny for a mere $250. An external would've cost me upwards of $1000 without guarantee that it even worked. So that's why internal. With quality parts I shouldnt have problems with the internal slave for a long time.

The part number on the case is 53009528 which is listed as a 92/93 internal slave with a large input shaft. Or at least that what the guy at the Dodge dealership told me. I pulled the transmission from a rig with a build date of 3/93. Also the bell housing doesn't have any holes where the external slave would go, only a rubber piece where the internal slave lines go through.

I can't get pictures to upload right now but I will try tomorrow.

I appreciate all the help guys. This has confused me pretty good.

I just got back from a parts run. My pressure plate and friction disk match the parts from Napa, O'Reilly's, and AutoZone so I feel confident in the thought that they are correct. The slave cylinder is hard to compare because the ones from the store are not expanded. The question I have now is whether or not I was sent a slave from a 4 cylinder. They appear almost identical in pictures but have a slightly different bore size and are different part numbers. Does the 4 cylinder slave have a smaller stroke than the 6 cylinder? Could this be my issue?

It's unfortunate to hear you are having such trouble with brand new parts. I did the swap a long time ago. Took a 99 ax15 and put it in my 92 xj. Later after I cracked my bellhousing I had to swap in a 92 ax15 with an internal slave. Still using the internal slave set up now...

Some things that I remembered is that I never needed to change pilot bushing when I took out the 99 ax15 and put in the 92 ax15. Also can you verify that the metal straps containing the internal slave cylinder broke free? That will keep the slave from acting normal. Does your clutch pedal go all the way to the floor?

themauler said:

It's unfortunate to hear you are having such trouble with brand new parts. I did the swap a long time ago. Took a 99 ax15 and put it in my 92 xj. Later after I cracked my bellhousing I had to swap in a 92 ax15 with an internal slave. Still using the internal slave set up now...

Some things that I remembered is that I never needed to change pilot bushing when I took out the 99 ax15 and put in the 92 ax15. Also can you verify that the metal straps containing the internal slave cylinder broke free? That will keep the slave from acting normal. Does your clutch pedal go all the way to the floor?

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I know that the input shaft sizes were hit or miss for a couple years same with tbe crankshaft end bore. Most '91 and '92 kits I've seen come with two different alignment tools just in case. Yeah I took the transmission back off and checked, the bands had popped free and the slave worked fine it just doesn't seem to be as long as it needs to be. The pedal feels right and is able to actuate the master cylinder prop rod correctly. I even made a reinforcement plate for where the master bolts to the firewall to eliminate any flex in the firewall when the pedal is pushed, it doesn't interfere with the pedal movement in any way.

It appears that the bore diameters between the 6cyl and 4 cyl slaves differs by only a few thousandths of an inch so I will check my slave tomorrow with a micrometer. I'm hoping the slave is either defective or is for a 4cyl and just isn't the correct size.

Once again thanks for the help guys.