Off Roading Forums banner
1 - 3 of 3 Posts

·
Registered
Joined
·
1,020 Posts
Discussion Starter · #1 ·
Anyone swapped a 999 auto in place of a BA/10 manual.
258 engine and NP231 transfer case is staying

Just wondering if the 999 and NP231 will mate up and or what adapters and other garbage will I need.
 

·
Registered
Joined
·
965 Posts
I got good news and bad news.

The bad news. your np231 probably will not fit.

Good news, the input gear for the np231 can be swapped for one that does fit. And while you have the Tcase apart you can do the SYE thing.

I have never swapped the input gear to the np231, but the guys at j and b conversions said it was not that bad. But, I warn you that, My experience is with the early AX-15s, not the BA-10 or the 999. When I replaced my AX-15 with a remanufactured unit, lots of folks told me that the early AX-15s ( like in the 89 ½ YJ) had 21 splines like some of the BA-10s. So I had to de-bunk the roomers ( FYI, my NP231 had the short 23 spline input gear).

The input gear comes in a few flavors:
23 spline
21 spline
and
short
long( aka flush trans output)

The best reference I found is a PDF on the advance adapters web site.

http://www.advanceadapters.com/acrobat/jp1987up.pdf

hope this helps.
greg
 

·
Registered
Joined
·
4,143 Posts
I replaced my BA-10 with a TF-727. I put a NP-208J behind it. The 208 bolts up, has a fixed rear yolk, and is a hell of a lot stronger. However, it hangs down though the skidplate 2"
I've got to do something about that!

The swap cost me around $1000 total. $500 for the tranny, $150 for the x-case, $100 for a shifter, plus driveshaft mods and other odds-n-ends.

What it took:
*TF-727 from '86 G-Wagon (with torque converter)
*Flywheel from '84 CJ-7 with 258/TF-999 combonation
*Starter for an '86 G-Wagon (starters go by trannys, not by engines)
*Starter solenoid for '86 G-Wagon, and some funky wiring.
*Kick-down linkage from '76 DJ-5d with 232/TF-727 combonation. If you can just get a good look at what this does, you can easily hand-bend your own if you get a little creative.
*Transmission cooler and hoses.
*Driveshaft mods. The front diveshaft had to be shortened ever-so-slightly. The rear driveshaft was a cut-down XJ piece from a junkyard ('86 XJ with "select-trac" so it had the NP-228 x-case and correct driveshaft parts). I had them install all-new U-joints with zerk fittings that stick out of each cap for easy greasing.
*Shifter. I screwed up here and got the B&M Z-gate shifter. It's only suitable for cars (too short). The B&M Megashifter is the truck model. (I'll make a tranny-mounted, linkage-style shifter when I get some fabrication tools). I got the J-10 x-case shifter and mix-matched and fabbed up some parts to make it work- still very tough to shift though.

An AMC V-8 is in the works
 
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top