i want to ditch the 5spd pewww-geot for an auto. correct me if i'm wrong, but i think it has a 21 spline output, so whatever auto i install will probably have a 23 spline output? then i will have to change the input on the 231.

if i'm correct so far.........

would a TF999 be the hot set-up?

if not, in your opinion what swap would be the best bet?

thanks for any help on this :)

999 will be a direct bolt in except for the 21 spline issue. Just change the input on your 231 and be done.

thanks slut

and i'm sure both driveshafts will need to be lengthened/shortened. probably some tub issues for both t-case and tranny shifters too. how about any electrical sensors- probably some issues there too.

thanks

With your YJ being an 87, there's nothing electrical about it :) I did this swap from a puegot to a TF999. If you are still running a carb, there are going to be some parts that are going to be hard time find. The kickdown linkage will have to be a junkyard. I do know that when I was looking for a flywheel for the tranny, I only found one, and it was in San Jose. You will also need a shifter ( I used a floor shifter) and a shifter cable, that is about 8 feel long. If you don't want to spend a whole BUNCH of money, try to find a tranny that includes the torque converter, unless you are planning on a rebuild, and using a performance torque converter. If you have any questions, just let me know. I got done with my swap about 9 months ago, and I will never own a manual jeep again. I love the auto!
Scott

someone correct me if im wrong, but i thought the np231 wasnt used until 88. in 87 didnt they use the np207?

Originally posted by 87JeepWrangler
someone correct me if im wrong, but i thought the np231 wasnt used until 88. in 87 didnt they use the np207?

i guess the 231 was put in some cause i have one and it is stock. i have installed an SYE. it says right on the tag "new process 231", 2.72 and a date like feb87- i can't remember exactly.

ok then, learned something new.

was reading this info:





The Torque Flite 999 is a medium duty Chrysler 3 speed automatic transmissions. They have an aluminum case and a 23 spline output shaft. The case is ??" long and ?? bolts hold in the pan.

Modern versions are still use the 23 spline output, but engine bolt patterns have changed and the newer ones have electronic shift control. I have conflicting information about torque converters. Some say early models did not have a lock up torque converter and some say they did. Newer models have a lock up torque converter.

Usage
The TF 999 was used in CJs from 1980-1986 only with the I6 and V8 engine. It was also used in 1984-1990 SJs and J pickups with the 4.2L engine, in the YJ from 1987-1991 with the 2.5L and 4.2L engine, and in the XJ in 1991 with the 2.5L engine. A modern version of the 999 continues to be used in Wrangler YJs and TJs to this day with the I6 engine.

Transmission 1st 2nd 3rd 4th 5th Rev
TF 999 2.74 1.55 1.00 2.20


what is a locking torque converter?
sounds like i want one from the YJ's to match my 4.2 bolt pattern.

Do you have the 4 or 6 cyl? I would go with a 700r4 and grab one w/ a tcase already attached.

dont forget about the TF727