AMC Manual Transmissions - General Info

[Alcoatari]

Another heads-up if anyone tries to mate a 247 to the AX15:

The AX15 output shaft is a little bit too long. I don't know if there is an adapter available, but I don't really want to add anymore length, the AX15 is already longer than the SR4. My plan is to shorten that shaft by 9/16."

After that, the two will finally marry.

Why didyou not go with the 249? They bolt right up to the ax15, as does the stock eagle case....

Our stock TC bolts to the AX/15 I was under the imression there was no way.

lol, I couldn't make it fit without about a half inch gap between the two... Just my experience, maybe my garage is located in the twilight zone.

[tougeagle]

Another heads-up if anyone tries to mate a 247 to the AX15:

The AX15 output shaft is a little bit too long. I don't know if there is an adapter available, but I don't really want to add anymore length, the AX15 is already longer than the SR4. My plan is to shorten that shaft by 9/16."

After that, the two will finally marry.

Why didyou not go with the 249? They bolt right up to the ax15, as does the stock eagle case....

Our stock TC bolts to the AX/15? I was under the imression there was no way.

I have pictures of the comparisons somewhere. Maybe my trans is unique. It was said to be from a 90 or 91, but it had external slave bellhousing and .75" input, found on 96-up IIRC

[Alcoatari]

Another heads-up if anyone tries to mate a 247 to the AX15:

The AX15 output shaft is a little bit too long. I don't know if there is an adapter available, but I don't really want to add anymore length, the AX15 is already longer than the SR4. My plan is to shorten that shaft by 9/16."

After that, the two will finally marry.

Why didyou not go with the 249? They bolt right up to the ax15, as does the stock eagle case....

Our stock TC bolts to the AX/15? I was under the imression there was no way.

I have pictures of the comparisons somewhere. Maybe my trans is unique. It was said to be from a 90 or 91, but it had external slave bellhousing and .75" input, found on 96-up IIRC

, I so wish it had been that easy for me haha

[Alcoatari]

And you are right Tougeagle, I would have sworn on a stack of bibles that the stock t-case would have fit, but it wouldn't, try as I may.

[captspillane]

Your 5 speed options are as follows:
1) T5 transmission rated at 265 ft/lbs. This is the five speed original to Eagles and CJs. It is a very small casing and prone to breaking in a bunch of ways. It shifts very nicely and doesn't weigh much, but its really just intended for cars. Don’t get a T5 if you’re going to tow with your Eagle.

2) "World Class" T5 transmission. These are common in Ford Mustangs but do not adapt to our transfer cases easily. Some people take the Jeep T5 and swap in most of the "World Class" parts, but it’s not even remotely worth your time. When they're finished the case is still prone to warping under torque and it is still considerably weaker than an AX15 or NV3550.

3) AX15 Transmission rated at 285 ft/lbs: This is found behind the 4.0 in Wranglers and Cherokees from around 1990 to 1998. I forget the exact years. This transmission shifts very nicely and is also very strong. It’s very common and is the easiest transmission to find at a junkyard. Early AX15s had an internal slave cylinder and later ones are external. Either one works fine, but I would prefer the internal slave cylinder because it has a normal 3/16 double flare input versus the crazy pin and o-ring input the external slave cylinder has. You must use a 4.0 flywheel with this transmission because the 4.2 flywheel is a quarter inch thicker. The T5 clutch is the same, but the pilot bearing is different for the AX15 and NV3550. Instead of a brass plug the AX15 and NV3550 have a thin roller bearing pressed into an aluminum spacer that in turn is pressed into the end of the crankshaft. Make sure you get the roller bearing and aluminum spacer together, since you can’t remove the bearing without damaging the spacer. I first bought mine at Autozone and only the roller bearing part came. I then bought it at Advanced and the two came together for the same price.

4) NV3550 rated at 300 ft/lbs: This is the strongest five speed found in factory Jeeps. It replaced the AX15 around 2000 until 2004. Advance Adaptors sells the external slave cylinder with a stainless mesh flexible input line and the brass adaptors it needs. With that kit you just need to make a short piece of double flare brake line from your Eagle clutch master cylinder to the flex line. You must use the correct fluid or you’ll damage the synchros.

If you’re installing it behind a 4.2 or 4.0 you should retain the NV3550 bellhousing and 4.0 flywheel so that your fuel injection has a place for the crank sensor. If you’re installing it behind an AMC V8 you cannot use a 4.0 flywheel because V8s are externally balanced. In that case use an Advanced Adaptors kit that mounts between the NV3550 and a T5 bellhousing (Its basically a 3/4 inch thick spacer). That retains the bigger flywheel and all the original shift linkage.

5) NSG370 6 speed transmission rated at 272 ftlbs: This replaced the NV3550 in Jeep Wranglers. They’re very rare but not impossible to find. Only a NSG370 from a 2005 or 2006 4.0 Jeep Wrangler has the AMC bolt pattern. They still use the NSG370 today in Jeeps, but the bellhousing cannot be removed from the transmission so 2007 and newer Jeeps have a Chrysler bolt pattern and are useless to us. This transmission has a 4.46 first gear and a 0.84 overdrive in contrast to the 3.83 first gear and 0.79 overdrive in an AX15. This means that you should use 3.07 gears with a NSG370 to get the same shift points you would have with an AX15 mated to 3.55 gears.

6) AX5 transmssion: Its a very weak transmission easily confused with an AX15. Don't use it. Only 4.0 Jeeps have the AX15.

7) NV4500 rated at 460 ft/lbs: This is a true truck transmission. It’s literally twice as heavy as a T5, it shifts clunky like a truck, and it is easy to adapt to our engines and transmissions but it’s not easy to fit under our Eagle floorpan. This option should only be considered if you have a 401 in front of it and a custom Dana 60 axle behind it.

[captspillane]

This picture shows my NSG370 6 Speed to the far left. Next to it is the NV3550 5 speed. There are two T5s sitting to the right of that. The second picture shows an AX15. The third picture shows the crank position sensor hole on the NV3550, AX15, AW4, and TF999. The fourth picture shows the crank position sensor hole on the NSG370. The notches in the flywheel are identical, but clocked differently because the 6 speed hole is on the side. The engine will not run if you use a 5 speed 4.0 flywheel with the 6 speed. I'll have to get a better picture of the AX15 next to the NV3550 next time I'm home.

[standup650]

4) NV3550 rated at 300 ft/lbs: This is the strongest five speed found in factory Jeeps. It replaced the AX15 around 2000 until 2004. Advance Adaptors sells the external slave cylinder with a stainless mesh flexible input line and the brass adaptors it needs. With that kit you just need to make a short piece of double flare brake line from your Eagle clutch master cylinder to the flex line. You must use the correct fluid or you’ll damage the synchros.

If you’re installing it behind a 4.2 or 4.0 you should retain the NV3550 bellhousing and 4.0 flywheel so that your fuel injection has a place for the crank sensor. If you’re installing it behind an AMC V8 you cannot use a 4.0 flywheel because V8s are externally balanced. In that case use an Advanced Adaptors kit that mounts between the NV3550 and a T5 bellhousing (Its basically a 3/4 inch thick spacer). That retains the bigger flywheel and all the original shift linkage.

Have you done this behind the 4.2? Is it pretty bolt in? And are bolt on t case options limited?

[Alcoatari]

3) AX15 Transmission rated at 285 ft/lbs: This is found behind the 4.0 in Wranglers and Cherokees from around 1990 to 1998. I forget the exact years. This transmission shifts very nicely and is also very strong. It’s very common and is the easiest transmission to find at a junkyard. Early AX15s had an internal slave cylinder and later ones are external. Either one works fine, but I would prefer the internal slave cylinder because it has a normal 3/16 double flare input versus the crazy pin and o-ring input the external slave cylinder has. You must use a 4.0 flywheel with this transmission because the 4.2 flywheel is a quarter inch thicker. The T5 clutch is the same, but the pilot bearing is different for the AX15 and NV3550. Instead of a brass plug the AX15 and NV3550 have a thin roller bearing pressed into an aluminum spacer that in turn is pressed into the end of the crankshaft. Make sure you get the roller bearing and aluminum spacer together, since you can’t remove the bearing without damaging the spacer. I first bought mine at Autozone and only the roller bearing part came. I then bought it at Advanced and the two came together for the same price.

I used whatever flywheel came off the 4.2 (Kragen Crate) and so far everything has been fine. Is it possible that later 4.2 crate motors used the thinner flywheel as seen in the 4.0?

If not, what are the potential issues with the 4.2 flywheel being a 1/4 inch thicker?

[doc65]

On a manual I would expect very little issue if everything bolted together without binding.  it the clutch disk doesn't hit the front bearing retainier/throwout bearing guide, and the preasure plate has clearance, oh and the throwout bearing still has room to move backward as the clutch disc wears then it should be fine.  On other engine/trans swaps decades ago I remember having the choice between a diaphragm, Borg & Beck or Long Style preasure plate, you just had to make sure to match the throw out to the preasure plate style that you were using.

Now an auto trans is a different story, the offset that is pressed into the flex-plate(when they aren't just flat that is) can put the snout of the torque converter too far in or not far enough, and can either leak like a seive, or damage parts 

Doc

[Alcoatari]

Thanks for the quick reply and thorough response.

Your knowledge is so appreciated.

Really, all of you guys were a great resource for my project.

Thanks.

[captspillane]

The hydraulic system does have enough play to account for the difference in thickness but you will need to account for it with the length of your pushrod. A mechanical linkage from a CJ has a screw in adjustment to the length of the pushrod, so you could adapt one of those as a means of adjusting it, or you could experiment and find what works. I personally am not willing to deal with making it work, and there is a possibillity that it won't work.

I had a nightmare with my Spirit when I switched from 9" clutch to 10" clutch. It should work but it doesn't. The mechanical linkage didn't have quite enough adjustment. I'll never put my self through that again.

I do have an AX15 internal slave, NSG370 6 speed, and NV3550 external slave ready to install in an Eagle in my garage. My CJ8 Scrambler also has the Advanced Adaptors kit with T5 bellhousing, flywheel, clutch, and linkages with a NV3550 behind it. Any specific questions about them?

There are two types of 4.0 flywheels. The NSG370 CPS notches are clocked differently than the AX15 version, but its otherwise identical.

[Alcoatari]

The hydraulic system does have enough play to account for the difference in thickness but you will need to account for it with the length of your pushrod. A mechanical linkage from a CJ has a screw in adjustment to the length of the pushrod, so you could adapt one of those as a means of adjusting it, or you could experiment and find what works. I personally am not willing to deal with making it work, and there is a possibillity that it won't work.

I had a nightmare with my Spirit when I switched from 9" clutch to 10" clutch. It should work but it doesn't. The mechanical linkage didn't have quite enough adjustment. I'll never put my self through that again.

I do have an AX15 internal slave, NSG370 6 speed, and NV3550 external slave ready to install in an Eagle in my garage. My CJ8 Scrambler also has the Advanced Adaptors kit with T5 bellhousing, flywheel, clutch, and linkages with a NV3550 behind it. Any specific questions about them?

There are two types of 4.0 flywheels. The NSG370 CPS notches are clocked differently than the AX15 version, but its otherwise identical.

Nah, I'm going to stick with the AX15 for now. I think it is a good pairing for the 247xcase, and If I ever decide to get into crawling or anything, I can always go for the 242. I see no real point in getting an automatic for either of these setups.

My concern was that the thicker plate would accelerate wear in some fashion. But as you said, I have a manual so I should be fine.

My Sx4 is all registered and drivable for the moment. My next project will be swapping the head for a 4.0 and building an exhaust... But I dont have a shop anymore, so that has to wait.

[javelinman74]

My T5 in the 82 Concord wagon crapped out again.

My question of need is I have a SR4 available and wondering IF that will bolt into the Concord where the T-5 lived, or is there enough of a difference that my mechanic shop will have too much to do to make it fit?

Its in the shop now...
Richard
[email protected]

[Alcoatari]

The SR4 should be a direct bolt-on behind the 258 or the 2.5, assuming you have the proper bell-housing. You may be able to use the T5 bell-housing, but I dont know for sure.

Also, is your SR4 out of a 4X4? If so, it will have a tail-shaft housing set up to bolt onto a Xfer case. If it is a 2WD SR4, then you should be good.

Hopefully one of the other guys can chime in about this.

[Alcoatari]

There is some good info at the beginning of this thread

http://forums.amceaglenest.com/index.php?topic=27.0