Yes you should drain and refill with new fluid each time

The small OEM trans cooler looks like this in pic



That sounds like a good fluid to use.. I use this stuff for my heep



The np242 is the transfer case,(New process 242) The 97 could have the np231 or the np242 you will have to look at the tag to make sure.




The np231 and the np242 are shift on the fly.. meaning you can shift them into 4 high 4-wheel drive at any legal speed..

these are the shift patterns for the np231 and the np242

231 shift patter
2H
4H
n
4L

242 shift patter
2WD
4PT/part time
4ft/Full time
N
4L

The np242/full time,,means the T-case can be used on dry pavement. 4PT/part time means loose gravel roads or off road only.

The np231 does not have ability to be used on pavement like the np242. It can only be used on loose gravel roads or off road(no pavement )

 

OP: Drain-and-fill 3-4 times discarding the drained fluid and putting fresh fluid in. You should measure what comes out and put an equal amount back in.

I don't think synthetic trans fluid in necessary in an XJ. In fact, if you put it in any higher mileage transmission with wear, it could "shock" it and cause failure. This is why you change the fluid gradually, over a period of miles.

I do think your lack of familiarity and experience with automatic transmissions is making you worry about overheating too much.

An auxiliary trans cooler under light load, normal driving conditions can cause over cooling of the fluid. A transmission, like an engine, needs a certain amount of heat to operate properly and efficiently. An automatic transmission is not considered to be truly warmed up until about 30 minutes of highway driving.

 

I didnt know just adding synthetic could cause shock/failure to a high mile trans. I thought sock/failure was do to it being force flushed then the synthetic added. hmmm thanks for the info Ill have to look into that a little more.

I kinda agree with you on the cooler making it too cold of temps if they by-pass the inner radiator heat exchanger and just add a cooler and live in a cold climate. But if you live in a hot climate I don't see any reason not to put one in to help keep the temps down.
I dont think hot climate ppl need to worry to much about over cooling.

But people in cold climates should not by-pass the inner radiator heat exchanger you will run the trans way to cold going down the highway in the winter.
I run my coolers after the inner radiator Heat-E and in the winter at 20f running down the highway 30mins Im at 120-125f, never goes any higher.
kinda little cold so I cover the B&M one and it comes up to 130f.
If I play around in the snow and not really moving fast to push air through the coolers, my temps will come up to about 157F sometimes higher.
In the summer at 70-75F I run down the highway for 30mins or longer my temps run about 165F to 170F. But if I sit still holding brake or wheeling my temps will get up fast to around 180f maybe more depending how hard the trans is working.
But having the coolers really helps to cool down the trans a lot faster once a little air gets moving through them.
side note::: I read my temps off of the hot line coming out of the trans before it goes into the radiator..

for ppl thinking whats this inner heat exchanger.
Pic of inner radiator heat exchanger/cooler.

 

Yes, or see my sig, #3.

Oh, by the way, since you moved to Montana, you are forgiven for that Toledo thing.

Hail and farewell, and all that.




Agreed. These things go forever under heavy usage on plain jane Dex/Merc.



I think that's probably urban legend, but why risk it?

 

I've had my AW4 evacuated about 4 times... started at 30K miles and had it done up to 120K miles.

I'm contemplating having it done again.. but I've gone 60K miles since the last flush.

.

 

If you just pump the fluid out and replace it, nothing bad will happen. I installed a cooler into mine because I drive into the mountains on a regular basis on undergeared axles and my trans tunnel gets hot enough to melt stuff in my center console and roasted the fluid in 15K. Most any trans will do well with new fluid.