Which clutch to choose?


YJcharlie

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Nov 30, 2020
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Hello all,
I'm pulling out the BA-10 and installing the ax-15. My jeep is the '87 yj with a 4.2
Looking at rockauto, I looked up an '88 wrangler since thats when the first full year of the ax15 trans was and see the clutch kits for the Pukeot trans, but the other kit just says for the Aisin one. I just don't know if its safe to assume thats the right one. What do you guys think? Also, any issues with flywheel or starter? I guess it would be great to know the details when converting from BA-10 to AX15 and whats actually needed as far as clutch kit, flywheel, starter, pressure plate etc
 
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YJcharlie

YJcharlie

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Joined
Nov 30, 2020
Messages
11
Location
Goodrich, MI
Hello all,
I'm pulling out the BA-10 and installing the ax-15. My jeep is the '87 yj with a 4.2
Looking at rockauto, I looked up an '88 wrangler since thats when the first full year of the ax15 trans was and see the clutch kits for the Pukeot trans, but the other kit just says for the Aisin one. I just don't know if its safe to assume thats the right one. What do you guys think? Also, any issues with flywheel or starter? I guess it would be great to know the details when converting from BA-10 to AX15 and whats actually needed as far as clutch kit, flywheel, starter, pressure plate etc
Hey folks, never mind on these questions. I found a ton of info out there on the swap so I'm all set. Time to start wrenching.
 

jeepjoe43

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Dec 4, 2020
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Black Canyon City, AZ 85324
I'm glad you found what you needed.
Going to be looking into an SM420 swap for mine to get rid of the awful AX5.
A bit more involved, but now that I'm upgrading the axles, I can do so.
Novak used to offer a kit, but not anymore.
So, now it's a junk yard scrounge and the mix and match game begins.
 
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YJcharlie

YJcharlie

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Goodrich, MI
I'm glad you found what you needed.
Going to be looking into an SM420 swap for mine to get rid of the awful AX5.
A bit more involved, but now that I'm upgrading the axles, I can do so.
Novak used to offer a kit, but not anymore.
So, now it's a junk yard scrounge and the mix and match game begins.
Deadjeep had the complete kit for me to do the conversion from the ba-10 to ax15. The ax5 are bad too? I know they are light duty, I have a parts jeep with the 4 banger and that trans. I half thought about using it. It seems like Jeep changed stuff every year making these swaps confusing for sure. The kit wasn't cheap but I wanted to simplified the install as much as possible.
Good luck on yours!
 
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jeepjoe43

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Thanks!
As I understand it, the AX5 and AX15 are different animals, and won't even bolt up between the two.
Yes, the AX5 is VERY light duty, I just have a 2.5 with the AX5, and I hate it.
I like the shifter up to the dash when in it's granny and having to apologize to my passenger for reverse.
Guess I'm just "Old School", but when it comes to a Jeep, gears are everything.
 

machoheadgames

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AX5 is relatively garbage although it can do okay behind a 4 banger if used with the proper fluid and if the axle gearing is low enough for the tires that you aren't hammering on it all the time to get up to speed. AX15 is much better and no, the two use fully different bellhousings so they are not interchangeable. The 2.5L has a GM bellhousing pattern from the old iron duke motors. The 4.0 and 4.2 share the same rounded pattern that that most AMC motors have, including the old CJ and Wagoneer 304, 360, and 401. You can not adapt an AX5 to a 4.0, although you can adapt an AX15 to a 2.5 with an adapter from Advance Adapters, or the Dodge Dakota bellhousing.

AX15 will be a good swap, although since you asked about clutches (and even though got your answer), what year AX15 are you going with? I HIGHLY recommend going with an external slave setup if you can. The year AX15 you got will make a big difference on what all you need to get the swap done. If you can answer that, that will help get answers back for pilot bearing, slave cylinders, throwout bearings, etc.

Also, measure the pilot tip of the transmission. It will either be 0.59" or 0.75". That will make a difference on what you need too.
 
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YJcharlie

YJcharlie

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Goodrich, MI
AX5 is relatively garbage although it can do okay behind a 4 banger if used with the proper fluid and if the axle gearing is low enough for the tires that you aren't hammering on it all the time to get up to speed. AX15 is much better and no, the two use fully different bellhousings so they are not interchangeable. The 2.5L has a GM bellhousing pattern from the old iron duke motors. The 4.0 and 4.2 share the same rounded pattern that that most AMC motors have, including the old CJ and Wagoneer 304, 360, and 401. You can not adapt an AX5 to a 4.0, although you can adapt an AX15 to a 2.5 with an adapter from Advance Adapters, or the Dodge Dakota bellhousing.

AX15 will be a good swap, although since you asked about clutches (and even though got your answer), what year AX15 are you going with? I HIGHLY recommend going with an external slave setup if you can. The year AX15 you got will make a big difference on what all you need to get the swap done. If you can answer that, that will help get answers back for pilot bearing, slave cylinders, throwout bearings, etc.

Also, measure the pilot tip of the transmission. It will either be 0.59" or 0.75". That will make a difference on what you need too.
The ax15 I have is the external slave and has the .75 tip. I don't know its year though. The setup came with the master and slave cylinders but also the clutch/pressure plate and flywheel (plus drive shafts and trans mount) All old but not sure what it was bolted to, a 4.0 or 4.2. Once I get off my butt and pull out my trans setup from the jeep I'll be able to compare. But, I'm pretty sure I just need to order the new clutch/pressure plate/flywheel for my 4.2 and it should work. The drive shafts that came with the kit look pretty crusty though and I assume they are different than what I have on the jeep currently. I'll compare those as well once removed.
 
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YJcharlie

YJcharlie

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Goodrich, MI
The ax15 I have is the external slave and has the .75 tip. I don't know its year though. The setup came with the master and slave cylinders but also the clutch/pressure plate and flywheel (plus drive shafts and trans mount) All old but not sure what it was bolted to, a 4.0 or 4.2. Once I get off my butt and pull out my trans setup from the jeep I'll be able to compare. But, I'm pretty sure I just need to order the new clutch/pressure plate/flywheel for my 4.2 and it should work. The drive shafts that came with the kit look pretty crusty though and I assume they are different than what I have on the jeep currently. I'll compare those as well once removed.
Oh, and I need to get the new pilot bearing too.
 

machoheadgames

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The ax15 I have is the external slave and has the .75 tip. I don't know its year though. The setup came with the master and slave cylinders but also the clutch/pressure plate and flywheel (plus drive shafts and trans mount) All old but not sure what it was bolted to, a 4.0 or 4.2. Once I get off my butt and pull out my trans setup from the jeep I'll be able to compare. But, I'm pretty sure I just need to order the new clutch/pressure plate/flywheel for my 4.2 and it should work. The drive shafts that came with the kit look pretty crusty though and I assume they are different than what I have on the jeep currently. I'll compare those as well once removed.
Okay year doesn't matter anymore, I have all the details I need to know. 0.75" tells me it's at least a 92 and the external slave tells me it's at least a 94 (and would have also answered the pilot tip question due to age).

If it has a shifter or shifter base with the stub shaft sticking out, a picture of that would tell me if it's a YJ or TJ model transmission. Doesn't really matter except that you will want the YJ shifter.

You will need a special pilot bearing or bushing (I don't remember which) but it is what people use to adapt a 0.75" AX15 to a 91 4.0 or any 4.2. The AX15 back in those years were 0.59" as were the Peugeots. So that will definitely be an issue. After searching, I believe it is the 7501357 part number listed at Novak. Looks to be a bushing and not a bearing. No big deal either way.

Also, buying clutch disc and pressure plate should work, and so will the 4.2L flywheel, but you will need to order a throwout bearing for a 94+ Jeep. Mopar still sells the factory one that was used 1994-2018 #53008342. You might also need the clutch fork and some of that type of hardware stuff (pivot ball, clutch fork retainer spring which holds the fork in place on the pivot ball inside the bellhousing).

Make sure bellhousing has the studs for the slave cylinder to go onto, you will need those. They can be bought new if needed.

Not sure what the kit contained, master cylinder may or may not bolt onto the firewall. The 87-90 master cylinder was different than 91-95. If they supplied you with the 91-95 model, you'll need to adapt the slave to your existing stuff or buy new. Or modify the firewall for the later model MC. I know some people have done that and I would prefer that overall so you can buy a prebled master cylinder/slave cylinder assembly (more reliable than assembling and bleeding), but I don't know what they did to make it happen. May have involved welding or fab work.

I think driveline lengths stay the same so you may not need the driveshafts you got, but you'll be good to go if you do.

You will probably need a new transfer case shifter, the brackets seem to be different for every single transmission/engine combination. they can be found for around $100. They bolt to the transmission, so that's why it matters.

That's all I can think of for now, hope that helps.
 
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YJcharlie

YJcharlie

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Okay year doesn't matter anymore, I have all the details I need to know. 0.75" tells me it's at least a 92 and the external slave tells me it's at least a 94 (and would have also answered the pilot tip question due to age).

If it has a shifter or shifter base with the stub shaft sticking out, a picture of that would tell me if it's a YJ or TJ model transmission. Doesn't really matter except that you will want the YJ shifter.

You will need a special pilot bearing or bushing (I don't remember which) but it is what people use to adapt a 0.75" AX15 to a 91 4.0 or any 4.2. The AX15 back in those years were 0.59" as were the Peugeots. So that will definitely be an issue. After searching, I believe it is the 7501357 part number listed at Novak. Looks to be a bushing and not a bearing. No big deal either way.

Also, buying clutch disc and pressure plate should work, and so will the 4.2L flywheel, but you will need to order a throwout bearing for a 94+ Jeep. Mopar still sells the factory one that was used 1994-2018 #53008342. You might also need the clutch fork and some of that type of hardware stuff (pivot ball, clutch fork retainer spring which holds the fork in place on the pivot ball inside the bellhousing).

Make sure bellhousing has the studs for the slave cylinder to go onto, you will need those. They can be bought new if needed.

Not sure what the kit contained, master cylinder may or may not bolt onto the firewall. The 87-90 master cylinder was different than 91-95. If they supplied you with the 91-95 model, you'll need to adapt the slave to your existing stuff or buy new. Or modify the firewall for the later model MC. I know some people have done that and I would prefer that overall so you can buy a prebled master cylinder/slave cylinder assembly (more reliable than assembling and bleeding), but I don't know what they did to make it happen. May have involved welding or fab work.

I think driveline lengths stay the same so you may not need the driveshafts you got, but you'll be good to go if you do.

You will probably need a new transfer case shifter, the brackets seem to be different for every single transmission/engine combination. they can be found for around $100. They bolt to the transmission, so that's why it matters.

That's all I can think of for now, hope that helps.
Awesome, good info in general and on the part numbers. Here is the kit I got from Deadjeep.com.

ax15 clutch stuff.jpg


ax15 front view.jpg


ax15 overall.jpg


ax15 shifter.jpg
 

machoheadgames

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Awesome, good info in general and on the part numbers. Here is the kit I got from Deadjeep.com.

View attachment 117283

View attachment 117284

View attachment 117285

View attachment 117286
Looks to have pretty much everything. It has the transfer case shifter so you're good there. YJ stick shifter so you're good there. It even has a transfer case, damn.

Slave cylinder studs are there so you're good on that too.

That master/slave cylinder assembly is a pre-bled unit. So you'd either want to adapt the slave to your existing line, replace your existing MC and line and adapt the slave to that, or modify the firewall to accept that master cylinder. I would eventually plan for all new master and slave cylinder regardless but those should get you going in the interim. You should be pretty much all set on the details.
 
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YJcharlie

YJcharlie

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Goodrich, MI
Looks to have pretty much everything. It has the transfer case shifter so you're good there. YJ stick shifter so you're good there. It even has a transfer case, damn.

Slave cylinder studs are there so you're good on that too.

That master/slave cylinder assembly is a pre-bled unit. So you'd either want to adapt the slave to your existing line, replace your existing MC and line and adapt the slave to that, or modify the firewall to accept that master cylinder. I would eventually plan for all new master and slave cylinder regardless but those should get you going in the interim. You should be pretty much all set on the details.
I think I'll try modifying the firewall for the current master cylinder if it isn't to hard to do. My welding sucks but I have a buddy...lol. This jeep isn't precious so I don't mind doing whats needed.
Well thank you for all the info it really helps and now I know more about what I actually bought!
I think the kit was 1200 from deadjeep, but then 300 more for shipping. I'm sure I could have peiced it together cheaper but really wanted to make it as easy as possible. I'm old now, so money isn't an issue lol.
 
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YJcharlie

YJcharlie

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I think I'll try modifying the firewall for the current master cylinder if it isn't to hard to do. My welding sucks but I have a buddy...lol. This jeep isn't precious so I don't mind doing whats needed.
Well thank you for all the info it really helps and now I know more about what I actually bought!
I think the kit was 1200 from deadjeep, but then 300 more for shipping. I'm sure I could have peiced it together cheaper but really wanted to make it as easy as possible. I'm old now, so money isn't an issue lol.
Here is my real baby!

rock3.jpg


motor2.jpg
 
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YJcharlie

YJcharlie

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Just an update, the ax15 is in and all working well. I did end up buying a new pre-bleed master/slave. It took a fair amount of mods to make it work but just drilling out stuff mostly, no welding. Finally this jeep is done. No more leaks and runs and shifts well!
 
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