I'm trying to buy a heavy duty torque converter for my 89 YJ with the TF999 tranny. Does anyone know if I need a lockup torque converter or a non lockup? Any help is appreciated. Thanks.
Jim

I do believe that 89 is non lockup style transmission.

Is there some way to tell? I have someone who did the writeup on the YJ FAQ telling me he's 99.9% sure it's lockup.

There must be somewhere I can chekc to be sure.... any ideas?

Call Chrysler

THe problem with the lockup is that if you have changed your gears or tire size it may not work. My 94 has the TF904, which is basically the same tranny but smaller for the 2.5L. I bought my jeep with 205/75s and it locked all the time. When i put 30s on, it did somtimes. When I put 33s on, it never locked. Then when i put 4.56s in, it did for a week then stopped for months. Then with an electric fan install, it worked for a week (I guess from gained horsepower) and then stopped........ I guess what I'm trying to say is that lockup torque convertors are so sensitive, it may not ever work. Having a 3 speed auto with no lockup sucks on the freeway, i get almost 4000 RPMS going 60-65. This sucks even more concidering my jeep is my daily drive. This is just my experience though, yours could be different.

I have a 94 YJ 4.0 with the 999 lockup. I have had 36/38.5 and 39.5" TSL's with 4.56 and 5.13 gears. My lockup has worked flawlessly under all circumstances.

I have a 94 YJ 4.0 with the 999 lockup. I have had 36/38.5 and 39.5" TSL's with 4.56 and 5.13 gears. My lockup has worked flawlessly under all circumstances.

Really?!?!?!? Gosh that makes me FREAKIN mad. I guess there's a problem with mine.... I took it to a tranny shop once but they didn't feel like messing with it. They had better things to do, like rebuild trannies and make lots of money. Now, I'm gonna have to find out what the heck is wrong with mine.

Originally posted by IndianaBlake


Really?!?!?!? Gosh that makes me FREAKIN mad. I guess there's a problem with mine.... I took it to a tranny shop once but they didn't feel like messing with it. They had better things to do, like rebuild trannies and make lots of money. Now, I'm gonna have to find out what the heck is wrong with mine.

What is the specs of your vehicle and what is the problem??????????????

94 YJ 2.5L 33" tires 4.56 gears (came with 3.73). Stock axles, stock t-case. It has the TF-904 3 speed automatic transmission with lock up

The problem is: the torque convertor won't lock up, and I have no clue why. In the summer I even flushed the tranny and put in the MOPAR ATF just in case someone had put in other fluid before me.

And like I mentioned further up, it used to work fine, but over the course of 2 years, it has stopped.

If you have a lockup style tranny and converter, and it's not locking up, get it checked/fixed asap. Driving at highway speeds without it locking up will toast it rapidly, according to the tranny person that I use. I've looked into, extensively, swapping a TF999 (from a TJ) into my TJ (that has a X-15).. One input from the PCM to the tranny is to the electric solenoid for the lockup. My PCM doesn't have that output and I've suggested just wiring it to a switch in the cab, which the tranny shop ( a well known, local shop, that only does auto's and does race vehicles, etc), said would be no problem, but they cautioned mulitple times to make sure that the lockup is activated at highway speeds. The valve bodies are different between lockup and non-lockup trannys (of the same type, such as the TF999).


:)
Fred

Called Chrysler... as usual, no help. Called the dealer too... nobody knew.

I'm trying to buy a torque converter for my 89 and I can't figure out whether or not is is a lockup. Any help is appreciated.

Jim

What would be the consequence of putting a lock-up type converter on a non lock-up tranny?

the differences between lockup TF and Non lock up torque flights:

the input shafts are different,the lockup style has a smooth nub on teh very end, and a hole in the end that goes thru teh shaft.

non lockup is splined all teh way to the tip and the hole is about 1/4 inch deep.

the valve bodys are the same, BUT there is an extra module bolted on top of the lockup trans with an "s" shaped tube about 3/8 in diameter on top of the valve body.

If its switched electronically then I think its called a 32rh, or something, IM not aware of any electronically controlled trannys that are still called torqueflights, but im sure someone can correct me on that.