- Location
- Rainy side of Washington
So. Since the "Everything you ever wanted to know about the AW4" thread went pretty well, here goes the next installment, everything you ever wanted to know about the AX15 (and all the things you didn't want to know about the AX5!)
There are many AX15s out there, in a variety of years. I know for a fact they're used in:
- 1989.5-1999 XJs, 4.0L
- 1989.5-1992 MJs, 4.0L
- 1989.5-1995 YJs, 4.0L
- 1997-199? TJs, 4.0L
- unknown year range Dakotas, 4 (both K-car 2.5L and AMC 2.5L - more on this later) and 6 (3.9L V6 - basically a 5.2L V8 minus two cylinders) cylinder.
- unknown year range Toyota 4runners, pickups, and Supras. They are known as the R150 series transmission in these vehicles.
- A large variety of other vehicles I won't cover here. Lots of GM stuff, surprisingly.
Torque rating is rumored to be approximately 300 foot pounds. Which is the same as the ratings on the NV3550 and NV3500 (often confused for each other) so careful about letting people tell you an NV3550 is stronger than an AX15. Jeep/Dodge switched to NVG manual gearboxes in the 1998-2000 timeframe, depending on which vehicle you're talking about. My suspicion is that it was because they were by then only ordering AW4s, AX15s, and AX5s from Aisin, knew XJ AW4/AX15/AX5 orders were coming to an end soon, and wanted to consolidate contracts with another supplier that was already producing 100% of their transfer cases and many of their fullsize Dodge manual transmissions (all Dodge 1500s-3500s use either an NV3500 or NV4500) to save money, but I have no proof for that statement (aside from the NV3550 being almost bolt-in into the spot an AX15 comes out of, which is abnormal unless it was designed as a replacement) so take it with a grain of salt.
Basically, this is a very common gearbox. People think they're hard to find, but they aren't. The only differences are in the bellhousing, input bearing retainer, input shaft, tailhousing, and output bearing retainer, aside from some inconsequential stuff. The 4.0L bellhousings are exactly as hard to find as you think they are, since they only came in jeeps, but if you just need a replacement transmission since you slagged yours and can swap your bellhousing over to the new one... they are not hard at all. Walk through the Dakota section of your local yard and at least one of the 4/6 cylinder ones will probably have an AX15 in it.
For instance, I used an XJ/YJ/TJ/ZJ/MJ 4.0L to AX15 bellhousing along with a 1997 Dakota 3.9L AX15 and dropped it straight into my 1998 XJ when I swapped it to 5 speed.
From now on, to save significant confusion, just assume I'm speaking of Chrysler/Jeep/Dodge family AX15s, not the Toyota ones or anything else.
There are a few parts that have year splits:
- input shaft pilot tip diameter: 1991 and earlier vehicles use a roughly 15mm pilot tip. 1992 and later vehicles use a roughly 19mm pilot tip.
- slave cylinder style: 1993 and earlier vehicles use an internal slave. 1994 and later use an external slave. The parts affected by this change are the bellhousing, clutch release hardware (fork, pivot ball, throwout bearing, slave cylinder, retention clips), and input bearing retainer / throwout bearing quill. You can swap that all over if you want.
And a few parts that have vehicle splits:
- The tailhousing/rear case half. XJs, MJs, ZJs, and Dakotas share a rear case half. YJs and (I believe) TJs share a different one - still looking to verify this. The only significant difference is the clocking angle of the transfer case mounting bolt pattern; I've put an XJ AX15 into a YJ without issue other than floor/crossmember clearance. This is 4wd specific, I'm not going to cover 2wd units as I don't know enough about them to make sure my info is correct.
- the shift lever and turret. YJs, TJs, and Dakotas have a tall one to accomodate the higher seating position relative to the transmission, XJs, MJs, and ZJs have a short one. You must keep the lever and turret from the same side of this split but can swap back and forth across it otherwise. For instance I have the Dakota shift turret and lever in my 1998 XJ and love it, it puts the shifter a couple inches from the steering wheel in first gear but keeps the shift throw about as long as it is on a stock XJ shifter. If you wanted to, you could cut a Dakota one down to make an XJ short shifter, too.
- the bellhousing. This is different depending on what engine the transmission came behind. Available bellhousings include the 2.5L K-car (Dakota 4cyl 95-, pretty useless to us), 2.5L Jeep (Dakota 96+ 2.5L poverty spec vehicles had an AX15 and an AMC/Jeep 2.5L engine - this is great if you're tired of blowing up AX5s, use this bellhousing and an AX15), 3.9L Dodge V6 (V6 Dakotas got this bellhousing), and 4.0L Jeep. You can use whatever you want from this list to connect an AX15 to your engine of choice, just be aware that you may have to play games with pilot bearings, clutch discs, throwout bearings, etc to make it all work.
All 4wd AX15s have a 23 spline output shaft. All have the same ratio set, as far as I'm aware.
Transmission internal info, "gotchas" for home rebuilders, etc:
- First and second gears use the same synchro ring.
- Third, fourth, and fifth use SIMILAR rings. Two will match, one will not. It will have a different angle on the dog teeth. When you reassemble your transmission, you MUST make sure that the new stop rings are installed such that the synchro with the different tooth angle matches up with the synchro sleeve that has a matching tooth angle, otherwise it won't shift right.
- It's easy to accidentally put the fifth gear synchro sleeve on backwards. Don't do this! It will NOT shift right. One end of the splines on the inside of the sleeve has dog teeth ground into it, the other is flat tipped. Make sure the dog tooth end faces AWAY from the midplate, at the fifth gear synchro + gears.
All years (that I am aware of) use the same input and output seals, so I'm not going to go into detail on that. You can buy em wherever you want.
Now, on to the AX5. If the Peugeot BA-10/5 is the dana 35 of transmissions, this is the 27 spline 8.25. It'll work, but be nice to it so it stays that way. Internally they look very similar to an AX15, but nothing is quite as strong and in general these are intended for much lighter duty, thus why they were used behind 4-cyl engines. I've seen a LOT of them blow up second or third gear. In fact I collected enough broken ones at one point that I got bored and put together a spare one entirely out of salvaged parts from a total of three donor transmissions. They have a different bolt pattern where the bellhousing bolts on, and all are 21 spline. Pilot tip is 0.590". There is a lot of picky stuff and a lot of year splits you need to take into account when choosing a donor for the bellhousing and transmission for simplicity of an AX5-to-AX15 swap, but all of them will work with enough work.
Note that you can play all sorts of games and do all sorts of interesting swaps with this info, especially the 4cyl and 6cyl Dakota bellhousing info. Most of them are a bad idea and will probably result in the death of your AX15, but let your mind run wild. For example, since the 4cyl Dakota bellhousing pattern matches an AMC 2.5L (which was designed to drop into an assembly line that was intended to put 151ci GM Iron Dukes and 2.8L GM V6s in things, and thus has a 60 degree GM V6 pattern) to an AX15, you could theoretically use it to put a 325hp late model Impala SS LS4 V8 in front of an AX15, or with a few holes redrilled, a 32 valve Cadillac Northstar. I wouldn't recommend this though as you'll probably blow the trans up in a hurry. You could also use this info to put a supercharged GM 3800 V6 in, which is a better idea (260hp/280ft-lb is not unmanageable for an AX15, and they're more compact than a 4.0 rather than less.) The 3.9L V6 bellhousing only fits Mopar family engines, but it enables things like a 2.8L Liberty CRD to AX15 mating, or a 5.2L/5.9L Magnum V8 to AX15 mating (also a bad idea, because a 5.2 probably isn't worth the complexity of this swap and a 5.9 will nuke an AX15 fast.)
That's about all I can think of, these are far simpler than the AW4 (and have far fewer differences year over year and vehicle to vehicle) and the changes are far easier to deal with since none of them involve wiring. I may do a teardown/rebuilder picture-by-picture guide if I get around to rebuilding my spare unit sometime soon. They're not overly complicated transmissions and anyone who can install an SYE successfully can probably rebuild one in anywhere from six hours to two days depending on the tools they have available and how much cleaning is done during the teardown. Rebuild kits are available for anywhere from $150 to $500 depending on where you buy it and who made (or repackaged) it.
Something I missed? Novak Conversions' page may cover it, if not, ask here and I'll explain if I can.
There are many AX15s out there, in a variety of years. I know for a fact they're used in:
- 1989.5-1999 XJs, 4.0L
- 1989.5-1992 MJs, 4.0L
- 1989.5-1995 YJs, 4.0L
- 1997-199? TJs, 4.0L
- unknown year range Dakotas, 4 (both K-car 2.5L and AMC 2.5L - more on this later) and 6 (3.9L V6 - basically a 5.2L V8 minus two cylinders) cylinder.
- unknown year range Toyota 4runners, pickups, and Supras. They are known as the R150 series transmission in these vehicles.
- A large variety of other vehicles I won't cover here. Lots of GM stuff, surprisingly.
Torque rating is rumored to be approximately 300 foot pounds. Which is the same as the ratings on the NV3550 and NV3500 (often confused for each other) so careful about letting people tell you an NV3550 is stronger than an AX15. Jeep/Dodge switched to NVG manual gearboxes in the 1998-2000 timeframe, depending on which vehicle you're talking about. My suspicion is that it was because they were by then only ordering AW4s, AX15s, and AX5s from Aisin, knew XJ AW4/AX15/AX5 orders were coming to an end soon, and wanted to consolidate contracts with another supplier that was already producing 100% of their transfer cases and many of their fullsize Dodge manual transmissions (all Dodge 1500s-3500s use either an NV3500 or NV4500) to save money, but I have no proof for that statement (aside from the NV3550 being almost bolt-in into the spot an AX15 comes out of, which is abnormal unless it was designed as a replacement) so take it with a grain of salt.
Basically, this is a very common gearbox. People think they're hard to find, but they aren't. The only differences are in the bellhousing, input bearing retainer, input shaft, tailhousing, and output bearing retainer, aside from some inconsequential stuff. The 4.0L bellhousings are exactly as hard to find as you think they are, since they only came in jeeps, but if you just need a replacement transmission since you slagged yours and can swap your bellhousing over to the new one... they are not hard at all. Walk through the Dakota section of your local yard and at least one of the 4/6 cylinder ones will probably have an AX15 in it.
For instance, I used an XJ/YJ/TJ/ZJ/MJ 4.0L to AX15 bellhousing along with a 1997 Dakota 3.9L AX15 and dropped it straight into my 1998 XJ when I swapped it to 5 speed.
From now on, to save significant confusion, just assume I'm speaking of Chrysler/Jeep/Dodge family AX15s, not the Toyota ones or anything else.
There are a few parts that have year splits:
- input shaft pilot tip diameter: 1991 and earlier vehicles use a roughly 15mm pilot tip. 1992 and later vehicles use a roughly 19mm pilot tip.
- slave cylinder style: 1993 and earlier vehicles use an internal slave. 1994 and later use an external slave. The parts affected by this change are the bellhousing, clutch release hardware (fork, pivot ball, throwout bearing, slave cylinder, retention clips), and input bearing retainer / throwout bearing quill. You can swap that all over if you want.
And a few parts that have vehicle splits:
- The tailhousing/rear case half. XJs, MJs, ZJs, and Dakotas share a rear case half. YJs and (I believe) TJs share a different one - still looking to verify this. The only significant difference is the clocking angle of the transfer case mounting bolt pattern; I've put an XJ AX15 into a YJ without issue other than floor/crossmember clearance. This is 4wd specific, I'm not going to cover 2wd units as I don't know enough about them to make sure my info is correct.
- the shift lever and turret. YJs, TJs, and Dakotas have a tall one to accomodate the higher seating position relative to the transmission, XJs, MJs, and ZJs have a short one. You must keep the lever and turret from the same side of this split but can swap back and forth across it otherwise. For instance I have the Dakota shift turret and lever in my 1998 XJ and love it, it puts the shifter a couple inches from the steering wheel in first gear but keeps the shift throw about as long as it is on a stock XJ shifter. If you wanted to, you could cut a Dakota one down to make an XJ short shifter, too.
- the bellhousing. This is different depending on what engine the transmission came behind. Available bellhousings include the 2.5L K-car (Dakota 4cyl 95-, pretty useless to us), 2.5L Jeep (Dakota 96+ 2.5L poverty spec vehicles had an AX15 and an AMC/Jeep 2.5L engine - this is great if you're tired of blowing up AX5s, use this bellhousing and an AX15), 3.9L Dodge V6 (V6 Dakotas got this bellhousing), and 4.0L Jeep. You can use whatever you want from this list to connect an AX15 to your engine of choice, just be aware that you may have to play games with pilot bearings, clutch discs, throwout bearings, etc to make it all work.
All 4wd AX15s have a 23 spline output shaft. All have the same ratio set, as far as I'm aware.
Transmission internal info, "gotchas" for home rebuilders, etc:
- First and second gears use the same synchro ring.
- Third, fourth, and fifth use SIMILAR rings. Two will match, one will not. It will have a different angle on the dog teeth. When you reassemble your transmission, you MUST make sure that the new stop rings are installed such that the synchro with the different tooth angle matches up with the synchro sleeve that has a matching tooth angle, otherwise it won't shift right.
- It's easy to accidentally put the fifth gear synchro sleeve on backwards. Don't do this! It will NOT shift right. One end of the splines on the inside of the sleeve has dog teeth ground into it, the other is flat tipped. Make sure the dog tooth end faces AWAY from the midplate, at the fifth gear synchro + gears.
All years (that I am aware of) use the same input and output seals, so I'm not going to go into detail on that. You can buy em wherever you want.
Now, on to the AX5. If the Peugeot BA-10/5 is the dana 35 of transmissions, this is the 27 spline 8.25. It'll work, but be nice to it so it stays that way. Internally they look very similar to an AX15, but nothing is quite as strong and in general these are intended for much lighter duty, thus why they were used behind 4-cyl engines. I've seen a LOT of them blow up second or third gear. In fact I collected enough broken ones at one point that I got bored and put together a spare one entirely out of salvaged parts from a total of three donor transmissions. They have a different bolt pattern where the bellhousing bolts on, and all are 21 spline. Pilot tip is 0.590". There is a lot of picky stuff and a lot of year splits you need to take into account when choosing a donor for the bellhousing and transmission for simplicity of an AX5-to-AX15 swap, but all of them will work with enough work.
Note that you can play all sorts of games and do all sorts of interesting swaps with this info, especially the 4cyl and 6cyl Dakota bellhousing info. Most of them are a bad idea and will probably result in the death of your AX15, but let your mind run wild. For example, since the 4cyl Dakota bellhousing pattern matches an AMC 2.5L (which was designed to drop into an assembly line that was intended to put 151ci GM Iron Dukes and 2.8L GM V6s in things, and thus has a 60 degree GM V6 pattern) to an AX15, you could theoretically use it to put a 325hp late model Impala SS LS4 V8 in front of an AX15, or with a few holes redrilled, a 32 valve Cadillac Northstar. I wouldn't recommend this though as you'll probably blow the trans up in a hurry. You could also use this info to put a supercharged GM 3800 V6 in, which is a better idea (260hp/280ft-lb is not unmanageable for an AX15, and they're more compact than a 4.0 rather than less.) The 3.9L V6 bellhousing only fits Mopar family engines, but it enables things like a 2.8L Liberty CRD to AX15 mating, or a 5.2L/5.9L Magnum V8 to AX15 mating (also a bad idea, because a 5.2 probably isn't worth the complexity of this swap and a 5.9 will nuke an AX15 fast.)
That's about all I can think of, these are far simpler than the AW4 (and have far fewer differences year over year and vehicle to vehicle) and the changes are far easier to deal with since none of them involve wiring. I may do a teardown/rebuilder picture-by-picture guide if I get around to rebuilding my spare unit sometime soon. They're not overly complicated transmissions and anyone who can install an SYE successfully can probably rebuild one in anywhere from six hours to two days depending on the tools they have available and how much cleaning is done during the teardown. Rebuild kits are available for anywhere from $150 to $500 depending on where you buy it and who made (or repackaged) it.
Something I missed? Novak Conversions' page may cover it, if not, ask here and I'll explain if I can.
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