Transmission Fluid Question

I recently purchased a 99 Cherokee Sport with about 95K miles. I am trying to decide whether or not to change the transmission fluid or not. I'm not sure if the previous owner ever changed the ATF fluid, but my best guess is no because of the condition of some of the other fluids I've changed. What's everyones input? Should I just do a partial fluid and filter change by dropping the pan? What about a flush? Or should I just leave it alone since there are nearly 100K miles and no record of previous service? Thanks for your advice.

Of course. Just looking for something to talk about. But I guess I'm just going to find some sarcasm... Sometimes, flushing the transmission fluid, if it hasn't been done by 60K-90K problems, can expose problems. Jiffy Lube won't even do the work unless you sign a waiver or can prove the transmission has been serviced within the first 90K miles. Buildup in the transmission fluid can cause a transmission with minor damage or wear and tear to continue to function properly. In some vehicles it's better to leave it alone if it's got high miles and never been changed. I was hoping someone in this forum had some experience with this issue particular to the Cherokee.

I would just pull the drain plug and then refill a couple of times. Maybe drop the pan and clean the screen, but that's about it.

Just pull a line and let it all pump out, or keep adding fresh fluid in till it runs clear. Then add a bottle of SeaFoam to it.

bump

does anyone have anymore input on this? I bought a 98XJ with 100K and no service records. I decided not to change it and now have 150K without problems. It's always in the back of my mind though.

I recommend changing the fluid, nomatter what the mileage
I myself have yet to cause a tranny to fail by changing the fluid
I have hear the stories but have never seen the damage

fresh tranny fluid is the lifeblood of a tranny, just like oil for the motor

that is stupid not to change it, so change it!

I've got 216K+ on mine with the original fluid. I've posted the same question here and on other boards. The consensus seems to be leave it alone. 216K with no slipping and no shifting problems. Just my .02

Jiffy Lube won't change it unless you sign a waiver? If that was coming from a reputable organization I might believe it, but c'mon...it's Jiffy Lube for crap's sake.

Why would you not change the ATF? You change the engine oil, diff oil, and t-case right? Just because it's working with what you think is the original fluid is no reason to think it won't be any better with fresh fluids.

Yucca-Man said:

Jiffy Lube won't change it unless you sign a waiver? If that was coming from a reputable organization I might believe it, but c'mon...it's Jiffy Lube for crap's sake.

Why would you not change the ATF? You change the engine oil, diff oil, and t-case right? Just because it's working with what you think is the original fluid is no reason to think it won't be any better with fresh fluids.

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Tis true, but he said Jiffy Lube will NOT FLUSH a tranny without a waiver. They will change it, but not FLUSH it. :wave:

Aye, but a flush is a change, and no matter how you word it, Jiffy Lube and Greasy Simian will never touch my vehicles....

Jim

The most important thing is to make sure the correct fluid is used!! If it's a 6 cylinder 4.0L it has a Asin Warner AW4 transmission and uses DEXRON fluid regardless what any parts counter person or dealer service writer tells you. If it's a 4 cylinder then the Chrysler fluid is used. And yes it should be changed. There's a debate about a "flush".

JoBo

Here is what you should do: Go to auto zone, buy a case of Castrol Dexron III for maybe $30, get under there, you will find a drain plug. It is easier than changing the oil. Drain it, then refill it. Drive 50 miles or so. Repeat. Drive 50 more miles, repeat again. You should be able to do the 3 drain and fills with the case, maybe 14 quarts, and you will have 100% clean tranny fluid. From then on, drain and fill once every 20,000 miles. If you really want a bullet proof tranny, install a cooler. I did when I got mine, and it is still flawless with 210K. Anyone who has 216K with the original fluid is lucky and waiting to walk a long way home.

tweber2 said:

Buildup in the transmission fluid can cause a transmission with minor damage or wear and tear to continue to function properly. In some vehicles it's better to leave it alone if it's got high miles and never been changed. I was hoping someone in this forum had some experience with this issue particular to the Cherokee.

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Anyone have a rebuttle to this aside from "change the fluid?" It seems logical that if your fluid is full of shavings/particulates that if you flush you'll end up with a fluid of significantly lower viscosity...hence slipping.

Jackhill442 said:

Anyone who has 216K with the original fluid is lucky and waiting to walk a long way home.

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So what do I have to gain by changing it? My guess is the damage is already done.
I started asking people whether to touch it about 100K miles ago. Most of the answers were to leave it alone.
The explanation I got was that the new fluid is very detergent like and it will free up all sorts of gunk that was in there and cause it to slip.
I called most of the tranny shops in town.
Another explanation was:
"The clutch packs get soaked with ATF. Over time, it becomes part of the chemical makeup of the disk. When you change the fluid, the fresh detergents will eat away the old stuff, causing it to slip"

that was my point: no sense in changing it now, you are likely going to have trouble soon no matter what. It is amazing that thing has lasted that long-a testament to the quality of Aisin Warner. I have seen many well maintained automatics fail at or before 100,000 miles.

shawnmahmud said:

Anyone have a rebuttle to this aside from "change the fluid?" It seems logical that if your fluid is full of shavings/particulates that if you flush you'll end up with a fluid of significantly lower viscosity...hence slipping.

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While you will get basically two answers to the question about changing auto tranny fluid
It is really a good idea to change the fluid at around 30 to 60 thousand miles
The fluid will be worn out at that point and will not perform its duties as it should
For years there has been the old wisdom that if the tranny has high miles don’t change it because it will cause trouble. (I have never had this happen)
On the other hand if the tranny is in good condition the fluid change will make the tranny last longer (this I do and have not had a tranny fail yet)

As for the idea that “shavings/particulates that if you flush you'll end up with a fluid of significantly lower viscosity”
Well I will say that any fluid that has a significant amount of shavings/particulates may leave a thick sludge in the bottom of the pan but the old worn-out fluid itself will actually have a lower “viscosity” due to the fluid will be broken down and will no longer hold a specified viscosity
So the new fluid would actually provide a boost in viscosity, and remember that you can drain the pan and refill 3-6 qt and this will help, then as recommended by another post change it again after a few hundred miles
And for anyone that has owned a vehicle and drove it for over 200k without changing the tranny fluid well I would agree you’re lucky and not wise about your vehicle care and at this point why even ask if you did not care to change it before why the sudden need to care?

Comanchedude said:

And for anyone that has owned a vehicle and drove it for over 200k without changing the tranny fluid well I would agree you’re lucky and not wise about your vehicle care and at this point why even ask if you did not care to change it before why the sudden need to care?

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Well I never intended to keep the vehicle for 13+ years. At about 100K miles, it beacame clear that I would be holding on to the Jeep for a while longer. That's when I started asking about high mileage tranny fluid changes. The overwhelming advice I got was not to change it over 100K miles if it had never been changed before. I'm hoping to keep the Jeep going for another 3 years (about 40K miles) if possible. It runs great now. Engine strong, tranny never slips, shifts great. So once again, I'll ask the question: if you had 216K miles on your original ATF would you change it now under my circumstances?