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post #1 of (permalink) Old 10-13-2002, 07:54 AM
sas87yj
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need auto tranny- best swap?

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
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post #2 of (permalink) Old 10-13-2002, 08:28 AM
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Re: need auto tranny- best swap?

The TF999 is a good medium duty auto that would be a good candidate for a 258 or a small V8. It would be the easy swap (not sure what motor you are running though). The TF 727 is a much heavier duty trans if you plan on beating it up, but anything would be better than that Peugot that is in there. Sorry, I cant help on the spline count, but I understood that all 231's (from Jeeps) were interchangeable...I have been wrong before though.
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post #3 of (permalink) Old 10-13-2002, 08:51 AM
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Re: need auto tranny- best swap?

i have the 258
i have done tons of wheelin in rocks and the pew-geot has survived it all. i believe the 999 will be strong enough for my needs. just want to get rid of the 5spd for an auto. the auto is the hot set-up for slow rock crawlin. i am going to burn out my clutch if i keep this up. a guy could do ok with a 5spd IF he had lower gears like the 4:1 in tcase and even a kluneV. BUT the pew-geot has got to go and may as well do the auto, which is what i want. just trying to get my best options and then start hunting one down.

thanks
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post #4 of (permalink) Old 10-14-2002, 12:51 AM
 
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Re: need auto tranny- best swap?

SAS,

You are correct about the spline count. The input gear also comes in long or short for NP232. The guys at J and B said it is easy to change the gear.

When I was buying a remanufactured AX-15, some guys told me that the early AX15 had the same spline count as the pew-goat. so I did a lot of looking and calling.


this link has a table and pictur of what has what.
link to advanvec adapters PDF on the 87-2001 jeep transfer case.link to PDF
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post #5 of (permalink) Old 10-14-2002, 06:33 AM
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Re: need auto tranny- best swap?

steve.. go with an TF727... its somewhat better than that 999.. and is more plentiful..
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post #6 of (permalink) Old 10-14-2002, 10:37 AM
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Re: need auto tranny- best swap?

It is true that all NV231s are not the same. Some have a 21 spling input and others have 23. The AX-5 is 21 spline and the AX-15 was 23. Not sure about the pou. But you can get a kit to change the 21 spline input to a 23 for less than $100.
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post #7 of (permalink) Old 10-14-2002, 12:25 PM
 
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Re: need auto tranny- best swap?

What makes the TF727 better, besides thae fact that it is stronger or is that the only reason? Also I have heard some horror stories of the front drive shaft hitting the tranny pan. What has to be done to prevent this from happening. I have been toying with the idea of putting an auto in my CJ. I did a search and the only thing I found was that you needed more than 4 inches of lift. I have a 4 inch lift on mine now. Is that sufficient? What can be done aside from more lift to prevent the problem? Limit up travel? I cringe from just thinking about that. Any help would be appreciated.
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post #8 of (permalink) Old 10-14-2002, 05:52 PM
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Re: need auto tranny- best swap?

The 727 is better only because it's stronger (if that can be an ONLY reason). The design of the two trannies are virtualy the same and they even look the same except the pan on the 727 has a goofy bump in it. That is what limits it's use in CJ's to those with 4" of lift or more. The driveshaft will hit that bump otherwise. I would imagine a YJ would not have this problem as the front shaft runs down the other side of the trans. The internals of the 999 are just a bit smaller than a 727, but if you are running a 258 and you havent broken that crummy French trans...you probably won't even bruise a 999. Just run a good quality cooler and a trans temp gauge and it will live a long, long time.
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post #9 of (permalink) Old 10-14-2002, 07:20 PM
 
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Re: need auto tranny- best swap?

How about the 727 is better because not only is it stronger, but it is more plentiful and even cheaper. ALL Grand Wagoneers from '80-91 that had the 360 (a couple- mostly Cali rigs -had 258s) came with a 727 with the AMC bellhousing and 23-spline output shaft.

That "funny bump" in the tranny pan is on the passenger side, so it interferes with the CJ-7s passenger-side front driveshafts. The YJ has a driver's side front driveshaft that seems to clear at even stock height. At least it does in my Jeep [img]images/graemlins/grin.gif[/img]

Instead of converting my 21-spline NP-231 (I also had a BA-10) to 23-spline, I sold it and bought an NP-208 from an '80s J-Truck (the NP-208 from behind a T-18 will not interchange). This way I gained a much stronger x-case (32 spline rear output!) and a fixed rear yolk. My only complaint is that it dearly needs to be clocked up out of harms way.

You can use a flywheel from a 258/TF999 '80s CJ
You'll need a starter and solenoid from an '86 Grand Wagoneer.
Use a tranny-mounted Lokar shifter.
You can do a search and find a complete write-up with pictures that I did a couple years ago on this swap. Put "TF-727/NP-208 Swap" into the search field.
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