What is the best auto transmission to put into a YJ? I have a 93 with the 4.0L, NP 231, and the stock auto tranny. I have already had to rebuild this tranny twice, and it seems to be slipping again. I am wondering if there is a better auto tranny I could swap in that holds up better to four wheeling. My jeep never sees pavement.
YJ auto tranny
- Thread starter 1993yj
- Start date
Brett
Meat-Hippy
- Location
- Salt Lake City Utah
Maybe try a 4 speed auto from the newer TJ's???
Brett
Meat-Hippy
- Location
- Salt Lake City Utah
- Location
- Grand Junction, CO
Do you have any kind of tranny cooler? Heat kills autos & rock crawling makes tons of heat. I'd try a aftermarket, heavy duty tranny cooler before spending the $$ on the adapters for a diffrent make of transmission.
Plenty of people are running that same tranny without problems, like RockMonkey. He uses his in a comp rig & is abusive to that thing. Far as I know, he's had no tranny problems.
Plenty of people are running that same tranny without problems, like RockMonkey. He uses his in a comp rig & is abusive to that thing. Far as I know, he's had no tranny problems.
RockMonkey
Suddenly Enthusiastic
Either I'm really lucky, or you're doing something wrong. I've got a YJ auto tranny in my comp buggy, as Greg said. The thing has been awesome. Tons of people use them hard and they have an excellent reputation. In fact a lot of people use the lighter-duty version of the 999 (the 904) with good results. I've had zero problems with it, other than keeping fluid in it when upside down. I have abused the crap out of that thing and never had an issue. I've slammed it from forward to reverse under power more times than I can count. I bought a spare from here when I saw one for sale cheap, but I've never needed it. I do run an aftermarket cooler. Perhaps it hasn't been adjusted correctly after the rebuild?
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RockMonkey
Suddenly Enthusiastic
This just popped into my head too. You are using a kickdown cable, right?
I would assume. I have never actually looked for it, but it seems to shift at the right RPMs. I am changing the fluid and filter again, trying that before I do anything drastic or expensive. There seemed to be just the normal amount of debris in the bottom of the pan. I think part of the problem is with the pick up. It usually will only slip when I am on a steep climb, such as Bump Dump.
I am also wondering if maybe the problems could be coming from my NP231 w/Currie slip yoke eliminator T-case? It feels more like a tranny problem, but I sometimes get a weird vibration from my rearend when starting off. It doesnt seem to be coming from my driveline, and I used to think that it was from my rear axle when I was running a D35, but I have since put in an 8.8, and I still get the same vibrations.
I am also wondering if maybe the problems could be coming from my NP231 w/Currie slip yoke eliminator T-case? It feels more like a tranny problem, but I sometimes get a weird vibration from my rearend when starting off. It doesnt seem to be coming from my driveline, and I used to think that it was from my rear axle when I was running a D35, but I have since put in an 8.8, and I still get the same vibrations.
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RockPaws
It's All About Rocks!
- Location
- Now Pahrump, NV
If it will not stay in "Park" you may need to adjsut the shift cable. If the adjustment is ok, the parking pawl or sprag may be damaged.
As for the transmission slipping, do you have a deep pan and filter pickup installed. Maybe the pump is cavitating, when your on an incline. If that is when this happens.
Frank
As for the transmission slipping, do you have a deep pan and filter pickup installed. Maybe the pump is cavitating, when your on an incline. If that is when this happens.
Frank
RockMonkey
Suddenly Enthusiastic
I'm running the stock pan on my buggy and have never had a problem on a steep incline. And I've been on some very steep ones.
The only time I've ever felt it "slip" was after I've been on my side, and lost a lot of fluid. After adding fluid it has always worked flawlessly. Maybe try just adding some fluid. Go ahead and fill it a bit above full. As much as I'd love to blame your woes on your transfer case, I can't really see any way for your t-case to fail that would cause that combination of symptoms. Rockpaws is right though, all your symptoms could be caused by your shifter not being adjusted properly.
RockMonkey
Suddenly Enthusiastic
Basically. The 32RH internally is identical to a TF999. To rebuild it you buy a 999 rebuild kit. Everything is the same except the 32RH has a Crank Position Sensor mounted on the bellhousing to make the YJ's fuel injection work. It's a 999 with a CPS. You could bolt a 32rh onto a CJ that has a 999 and it would work great. You can bolt the 999 from the CJ into the YJ and it will work, but you have to find some other way to mount a CPS. There are some aftermarket optins for that but they aren't cheap.
dbach
Active Member
- Location
- st george , ut
are the tf999 or 32rh computer controled [cps?]
RockMonkey
Suddenly Enthusiastic
No neither one is computer controlled. The 32rh has a provision on the bellhousing for a CPS. The 999 does not.
- Location
- farmington
Check your shifter adj. ASAP
sounds like kick down is ok.
stock pan is fine just run 1/2-1 quart over full. I have seen a lot of TF trannies loose pump suction on steep climbs and go neutral.
I ran one behind a 401 in a heavy rig for 5 or six years and it held up fine.
sounds like kick down is ok.
stock pan is fine just run 1/2-1 quart over full. I have seen a lot of TF trannies loose pump suction on steep climbs and go neutral.
I ran one behind a 401 in a heavy rig for 5 or six years and it held up fine.