What can I swap in place of my AX-5 transmission?

[S@pper_dan_man]

So my 90' Yj only has forth gear and that's it. I got it from my buddy who replaced the clutch plate just before he gave it to me. The tranny is original to the vic and I'm looking to just upgrade the thing. It's got the inline 4 2.5 and I'm not sure what I can marry up to it. I've seen AX15 and the 3550 as options but I'm pretty new to this and know nothing, please help!

 

[Fouledplugs]

So my 90' Yj only has forth gear and that's it. I got it from my buddy who replaced the clutch plate just before he gave it to me. The tranny is original to the vic and I'm looking to just upgrade the thing. It's got the inline 4 2.5 and I'm not sure what I can marry up to it. I've seen AX15 and the 3550 as options but I'm pretty new to this and know nothing, please help!

The AX15 can be mated to the 2.5. However a AX5 will bolt right in and is more than adequate to keep the 2.5 spinning the tires.

So I guess my only question is why not replace the AX5?

 

[S@pper_dan_man]

The AX15 can be mated to the 2.5. However a AX5 will bolt right in and is more than adequate to keep the 2.5 spinning the tires.

So I guess my only question is why not replace the AX5?

I want to replace it with something a little stronger. Ultimately I will, i just wanna know my best possible option ya know?

 

[Chris]

Go with an AX-15:

26-AX15 : Aisin AX15 5 Speed Transmission (NEW) | Advance Adapters

The AX15 transmission has always been a great transmission able to handle the torque and horsepower of most V8s. The biggest problem now is the availability of new units. With the lack of availability of new NV3550s, we revisited the possibility of obtain...

www.advanceadapters.com

 

[S@pper_dan_man]

Go with an AX-15:

26-AX15 : Aisin AX15 5 Speed Transmission (NEW) | Advance Adapters

The AX15 transmission has always been a great transmission able to handle the torque and horsepower of most V8s. The biggest problem now is the availability of new units. With the lack of availability of new NV3550s, we revisited the possibility of obtain...

www.advanceadapters.com

Thanks mang, you've been a yuuuge help

 

[Whiplash2130]

Go with an AX-15:

26-AX15 : Aisin AX15 5 Speed Transmission (NEW) | Advance Adapters

The AX15 transmission has always been a great transmission able to handle the torque and horsepower of most V8s. The biggest problem now is the availability of new units. With the lack of availability of new NV3550s, we revisited the possibility of obtain...

www.advanceadapters.com

Don’t forget to get the correct shift linkage and brackets when changing to the AX-15. Spend the time to change out the clutch, pressure plate, flywheel ( if necessary ) and most importantly the rear main seal. There’s nothing worse than having to take it apart and do it again!

 

[machoheadgames]

Go with an AX-15:

26-AX15 : Aisin AX15 5 Speed Transmission (NEW) | Advance Adapters

The AX15 transmission has always been a great transmission able to handle the torque and horsepower of most V8s. The biggest problem now is the availability of new units. With the lack of availability of new NV3550s, we revisited the possibility of obtain...

www.advanceadapters.com

The problem with that is it’s overkill for a 2.5 and the 5th gear is considerably higher than the AX5. So where the 2.5 already struggles on the highway, it will struggle even more. Of course you can just regear deeper but not really. This makes it to where 5.13 and 31’s is ideal, and 33’s no longer have a decent ratio as an option.

It’s also nowhere even close to bolt on. It requires either a Dodge Dakota bell housing that is almost extinct, or an expensive advance adapters kit. It also requires a special shifter adapter to reuse the stock shifter on the AX15, or you need to source an AX15 from eBay or something. New ones come with shifters but they are straight snd need to be bent up and painted. The transfer case also has to fully be taken apart to swap the input gear. That’s a lot of work for a transmission that is way too strong for a 2.5 and makes highway driving worse.

 

[machoheadgames]

I want to replace it with something a little stronger. Ultimately I will, i just wanna know my best possible option ya know?

So my 90' Yj only has forth gear and that's it. I got it from my buddy who replaced the clutch plate just before he gave it to me. The tranny is original to the vic and I'm looking to just upgrade the thing. It's got the inline 4 2.5 and I'm not sure what I can marry up to it. I've seen AX15 and the 3550 as options but I'm pretty new to this and know nothing, please help!

You don’t really need more strength. There are downsides to getting one of the stronger transmissions like I listed above. I would suggest sourcing another AX5. It’s a lot of work and money for something you don’t really need more strength from.

 

[Chris]

The problem with that is it’s overkill for a 2.5 and the 5th gear is considerably higher than the AX5. So where the 2.5 already struggles on the highway, it will struggle even more. Of course you can just regear deeper but not really. This makes it to where 5.13 and 31’s is ideal, and 33’s no longer have a decent ratio as an option.

It’s also nowhere even close to bolt on. It requires either a Dodge Dakota bell housing that is almost extinct, or an expensive advance adapters kit. It also requires a special shifter adapter to reuse the stock shifter on the AX15, or you need to source an AX15 from eBay or something. New ones come with shifters but they are straight snd need to be bent up and painted. The transfer case also has to fully be taken apart to swap the input gear. That’s a lot of work for a transmission that is way too strong for a 2.5 and makes highway driving worse.

Wow, I didn't realize it was that much work! I know a lot about swapping it into the 4.0 engines (in which case it is a good swap), but I didn't know that about the 2.5. The question is, is the AX5 as readily available as the AX15? I know the AX-15 can be had brand new for around $1600, whereas I think the AX5 is much more expensive and harder to find. I could be wrong of course, I haven't looked lately.

 

[machoheadgames]

Wow, I didn't realize it was that much work! I know a lot about swapping it into the 4.0 engines (in which case it is a good swap), but I didn't know that about the 2.5. The question is, is the AX5 as readily available as the AX15? I know the AX-15 can be had brand new for around $1600, whereas I think the AX5 is much more expensive and harder to find. I could be wrong of course, I haven't looked lately.

It’s definitely not as readily available, I do know there are some new ones floating around somewhere but they cost more than the AX15 and they are rare and only getting more rare. So yeah, really there is no perfect world for a 2.5 with a dying trans. My perfect world in that situation would be ditch the 2.5 and get something better in general.

I am a huge fan of the AX15, just think it’d a bit too much work for the 2.5 and brings with it downsides that make it even less worth doing. Doesn’t mean it’s a bad idea, just not what I consider ideal. It’s certainly an option and a pretty much unbreakable one behind that weaker engine.

 

[Whiplash2130]

It’s definitely not as readily available, I do know there are some new ones floating around somewhere but they cost more than the AX15 and they are rare and only getting more rare. So yeah, really there is no perfect world for a 2.5 with a dying trans. My perfect world in that situation would be ditch the 2.5 and get something better in general.

I am a huge fan of the AX15, just think it’d a bit too much work for the 2.5 and brings with it downsides that make it even less worth doing. Doesn’t mean it’s a bad idea, just not what I consider ideal. It’s certainly an option and a pretty much unbreakable one behind that weaker engine.

Then I guess I was lucky to pick a 2.5L already modified with a AX-15! She runs great now!

 

[Chris]

It’s definitely not as readily available, I do know there are some new ones floating around somewhere but they cost more than the AX15 and they are rare and only getting more rare. So yeah, really there is no perfect world for a 2.5 with a dying trans. My perfect world in that situation would be ditch the 2.5 and get something better in general.

I am a huge fan of the AX15, just think it’d a bit too much work for the 2.5 and brings with it downsides that make it even less worth doing. Doesn’t mean it’s a bad idea, just not what I consider ideal. It’s certainly an option and a pretty much unbreakable one behind that weaker engine.

Makes sense. I suppose when everything dries up and they no longer make even AX-15s, then you really just have to think about dropping in an LS (or something similar)

You could of course pair that with a slew of different transmissions.

Then I guess I was lucky to pick a 2.5L already modified with a AX-15! She runs great now!

Lucky you!