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Old June 3rd, 2016, 02:03 AM
Chuck78 Chuck78 is offline
Join Date: Jul 2014
Location: Columbus OH
Truck: 1962 GMC 1000 panel truck
Age: 44
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Default Re: 5 speed/o.d. swap - Aisin AX15 Jeep/Dakota trans

These AX15's came behind factory 4.0L & 4.2L V6 Jeeps putting out 280ft-lbs stock & get abused by the modified 4x4 crowd with very few complaints of failures, generally only failures due to wear and tear from people who don't know how to drive stick. One Jeep guy posted that he is making 311ft-lbs dyno'd and has 186,000+ miles on his 4x4 jeep ax15 and zero problems, and says it never gets driven mildly. Good to hear. Our GMC 305 V6's put out about 280 ft-lbs. The 351E puts out about 320ft-lbs. I think with careful use, occasional heavy trailer hauling in my 4000lb 62 GMC 1000 panel truck even if I put in a 351E would work out great. Once every year or 2 I need to tow a car on a dolly or trailer, but a motorcycle trailer will be the more common hauling use. This sounds like the best all around transmission for anyone not needing the serious extra capacity of the brute NV4500, and for normal driving, the 3.83 1st gear will be fairly useable as a 5 speed, whereas if not hauling major loads, the 5.## NV4500 1st gear gets skipped altogether under normal driving and you basically have a much heavier equivalent to the a833 my6 4 speed or 700r4 gearing.

These AX-15's have a 3.83:1 first gear, so this is still a very viable medium duty truck transmission with a gearing that will help with hauling loads.
Most have an electric speedometer output, which makes most vintage car/truck enthusiasts cringe at the black box speedometer conversion piece needed, but fortunately if you remove the electronic speedometer output, you will see the same standard drive and driven gears as what a cable driven speedometer uses, and then you will find that the cable driven speedometer output from many other older Chrysler transmissions bolts right in in place of this electronic speedometer output! Being popular in Jeeps which get modified heavily with different size tires and wheels, all sorts of various speedometer gear sizes are readily available from many sources to calibrate a speedometer.

Novak Adapters sells the adapter plate and many other accessories for this transmission 2 bolt to GM bellhousings. Unrelated to us, advance adapters sells a bellhousing to block adapter to take the Chrysler bellhousing and bolt it to a GM Block. This is of no use to gmc big block V6 power, however.

HERE IS A DETAILED AX-15 SWAP INTO A 1965 CHEVROLET C10, basically same as what ours would entail:

Aisin switched the AX15 to a larger pilot bearing inside diameter, and went from an internal bell slave cylinder setup to external slave cylinder & standard fork. I believe it was 92 on one of those mods (TO/slave cyland 1894 or 95 on the other. Novak sells both sizes of adapter pilot bearings or bushings to mate with GM crank shafts.
I believe the earlier versions were recommended to run GL5 gear oil, but some people complained that in 1997, they modified the transmissions for use with GL 3 gear oil. Apparently, the GL 3 is not even available from Chrysler anymore, and Jeep people complained about this transmission fluid not working as good anyhow. This made me wonder if 94 or 95-96 would be the best years of 4.0L & 4.2L Jeeps to source one from? Used pricing at local yards (pick n pull - $140-180) can be had for pretty cheap, and ebay/craigslist/expensive yards are asking $350-800 for these 2wd versions.

Apparently B&M make an aftermarket short throw shifter for these as well.

Last edited by Chuck78; June 3rd, 2016 at 05:45 AM.
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