Ax15

[buckenbronco]

Is an ax15 an ax15 or does it depend on what vehicle it came out of? Dodge,jeep,ford? Just as long as it is a 4x4.

 

[buckenbronco]

And is a good choice for fast ,sporty shifting?

 

[bronconut73]

That and the NV3550 are the sporty shifters for eb's.
The NV4500 and ZF5 are the heavy duty shifters for eb's.

 

[broncodriver99]

There are some differences. Internal clutch slave(early years) vs external clutch slave(later years) and the bolt pattern on the rear output may be clocked differently depending on the donor vehicle just like with the NV3550. As far as I know it was only used in three Jeep vehicles. Cherokee, Comanche, and Wrangler. No Dodge, Ford, or anything else. A similar but not interchangeable transmission can be found in Toyotas as that is where the original design came from. Toyota owns Aisin the AX15's manufacturer.

 

[buckenbronco]

Which is better external or internal slave? And should I look for a certain year

 

[demesauce]

Add the NP435 to the list of Heavy Duty transmissions

 

[broncodriver99]

Which is better external or internal slave? And should I look for a certain year

I don't know that it matters in a Bronco as the OEM slave is not used. Another difference is the early internal slave units have a 0.59" input shaft snout where the later external slave units have a 0.75" snout which could be considered a little heavier duty setup. The Advance Adapters kit comes with the components to deal with either setup so it is really just a matter of whatever year you come across.

 

[01JLH]

I have had both the NV3550 and the Ax15 in the same bronco behind the same motor and everything else remained constant. The NV3550 is just slightly more car like (sporty) than the Ax15. There are things like short throw shifters that i never tried, i just used the factory shifters. Both of the trans I have started out new so no issue of wear on either one. Both of these medium duty transmissions are far more "sporty" than any of the heavy duty trans mentioned. I have had all of them except the ZF.
All of the heavy duty transmissions require shifter bending and some form of modification to the major body cross brace/support up to completely removing the center portion because the shifter tower comes up so far forward under the dash.
The AX and nv3550 requires no modification to the body brace and the shifter comes out in the perfect place. Looks like it should have been there from the factory.
I am running the AX15 in my current build. Has turned out to be my personal favorite.

 

[chuck1022]

I have had both the NV3550 and the Ax15 in the same bronco behind the same motor and everything else remained constant. The NV3550 is just slightly more car like (sporty) than the Ax15. There are things like short throw shifters that i never tried, i just used the factory shifters. Both of the trans I have started out new so no issue of wear on either one. Both of these medium duty transmissions are far more "sporty" than any of the heavy duty trans mentioned. I have had all of them except the ZF.
All of the heavy duty transmissions require shifter bending and some form of modification to the major body cross brace/support up to completely removing the center portion because the shifter tower comes up so far forward under the dash.
The AX and nv3550 requires no modification to the body brace and the shifter comes out in the perfect place. Looks like it should have been there from the factory.
I am running the AX15 in my current build. Has turned out to be my personal favorite.

When you say no mods and the nv3550 will fit....my bronco is bone stoock, no body lift or nothing....the nv3550 will fit?

 

[buckenbronco]

Why do you like the ax15 over the nv3550

 

[Sporto]

When you say no mods and the nv3550 will fit....my bronco is bone stoock, no body lift or nothing....the nv3550 will fit?

I am interested in hearing about this and the AX-15. Thanks

Rich

 

[01JLH]

The conversion can be done with no body lift. Please take a look at where the bottom of your front grill crosses over the ends of the frame. If the grill is touching or very close to the frame your original body mounts are shot. There should be a good bit of space between the frame rails and the bottom of the grill.
I mention this because, even with good stock body mounts, space underneath the bronco is very tight. This makes working under there hard, even with stock parts. It makes the floorboards get very hot and can even make engine overheating problems worse because there is no place for the heat to go because of restricted air flow. Also this is why some folks have clearance issues with some intake,carb and breather combinations and others don't. Adding a 351 Windsor to the mix quickly takes up the little space that is there and some people immediately start experiencing overheating issues.
Do yourself a favor and go ahead and get a wild horses one inch body lift kit. It is new body mounts that give about 1 inch of clearance over new stock body mounts. They come with all the hardware needed in one easy kit.
If you get the complete advanced adapter kit for the Ax15 or Nv3550 it goes together like it was meant to be there and the finished installation looks like it was factory installed.
If your driveshafts fit before the conversion, they fit after. You have to make a small rectangular hole in thin sheetmetal only for the floor shifter. Sometimes you have to clearance the t-case shifter hole just a little if your t-case shifter makes contact with sheetmetal when shifting it into the different ranges, but not always.
Make sure you get the pigtail for the reverse light switch on the side of the transmission and move the wire from the bottom of the steering column to the side of the trans. If your reverse lights worked before the conversion, they will work after.
Pick up a smooth collar for the steering column and clean up the old shifting arm mounting point and it really does look like a factory install.
I cant really say anything about the exhaust system, some will have no issue, others will have to make minor mods, others will redo it all together. Stock exhaust manifolds work great, shorty headers work great, long tube headers have a lot of variations.

 

[01JLH]

As far as more info on the AX15, it is just my personal favorite. I believe it has more support out there in terms of replacement parts.
The one i have is a new one i got from Rockland Standard Gear. It is their "terminator" trans for high performance replacement primarily on jeep. It is rated for something like 450 ft lbs of torque. I heard a rumor that it was a AX15 case with Toyota internals. I believe Toyota owns AxisWaren(?) the manufacturer of AX15's. but that could be just rumor and not fact.
One thing about the Nv3550 that I don't believe is absolutely fixed is a problem that it wants to jump out of 2nd gear. There was an upgrade done that was supposed to fix this and my new Nv3550 was supposed to have had the upgrade. But i will tell you that, on a few occasions it did jump out. I think you just have to make sure you firmly pull it into 2nd. Sort of like double clutching but not quite.
I really liked the Nv3550, i just like the Ax15 a little more and never had the 2nd gear issue because it just shifts a little more positively.

 

[Sporto]

Thanks a lot of the info! I am in the planning stages for this upgrade. I really want to roll on the open road, and that overdrive is key to a comfortable ride for me.

One question, I do have and you may not know, but if I have a PTO winch on my Dana 20, would there be any problem with it and an AX-15? It sounds like from your summary, that it won't be an issue, but I am just asking all the questions that I can think of.

Thanks

Rich

 

[Pops68]

O1JLH:

I did the NV3550 conversion behind a 351 Windsor and NO body lift with NO clearance or install problems. Maybe a shop lift makes a difference??

BUT I have never heard of the over heating or floor heating issues before. My floors seem as they did prior to the swap (floor shifter 3 speed). Also, no overheating issues.

HOWEVER, I will keep this in mind in case these issues arise in the future.

Thanks for the info!!!!

 

[gooch66]

I am doing an AX15 swap right now and hopefully will be up and running tomorrow.

 

[01JLH]

I don't believe there is anything that would be in the way of the PTO coming off the side of the D20. I'm doing a frame off and have my frame ready to drop on the motor and trans next week. I will look closely when i get it bolted in and confirm.

 

[Sporto]

I don't believe there is anything that would be in the way of the PTO coming off the side of the D20. I'm doing a frame off and have my frame ready to drop on the motor and trans next week. I will look closely when i get it bolted in and confirm.

Great thanks! Post some pix too!

 

[Sporto]

Last question. I promise.

I can use my Stock clutch linkage and bell housing with this. I'm not concerned about the external or internal slave or the hydraulic clutch configuration of these correct?

 

[broncodriver99]

Last question. I promise.

I can use my Stock clutch linkage and bell housing with this. I'm not concerned about the external or internal slave or the hydraulic clutch configuration of these correct?

Correct. The factory Jeep stuff gets tossed and the stock Bronco bellhousing, linkage, and fork get used.