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Never Change Transmission Fluid & Filter?

TomSwift

NAXJA Forum User
Location
Florida
I left Pep Boys a little confused last weekend. I took my 98 xj there to have the serpentine belt replaced. While it was in there I figured it would be a good idea to have the transmission fluid and filter changed. I was told that if the fluid had not been changed within 36k miles it would be a bad idea to do it at this point. The old fluid would likely be heavier as it was full of sediment. Replacing this old fluid would cause the transmission to begin to slip.

After doing a quick search here on the forums I have found no posts about this. Any thoughts?
 
As long as you use the recommended trans fluid you should be fine.
 
B.S.
 
It can happen to cause it to slip. The dirt and debris that gets into the fluid can cause excessive wear and gaps that when you replace the fluid, the thinner fluid does not take up the gap. But it is very rare that changing the fluid will cause it to slip. I have changed many trans fluids that were black and over 100 thousand miles on the original fluid and never had any problems. In the many trans fluild flushes that i have done or seen done, i have seen 2 or 3 cars that it caused problems to. I have even seen a car take 3 trans flushes just to get the fluid to resemble red and it never had a problem. I would say do the flush. The odds of it causing problems is not worth the problems that not changing the filter and fluid. We recommend trans and filter changes about every 60,000.
 
While it was in there I figured it would be a good idea to have the transmission fluid and filter changed. I was told that if the fluid had not been changed within 36k miles it would be a bad idea to do it at this point. The old fluid would likely be heavier as it was full of sediment. Replacing this old fluid would cause the transmission to begin to slip.

What the heck??? That is total nonsense. The general transmission fluid replacement interval is 30k. So they are saying if you are 6k late, to NOT change your fluid? Okay; your first order of business is to never go back to that shop. That is just plain bad advice.

Now for your XJ. How many miles has it been since the last tranny fluid change? You may find some (including me) that might not recommend a flush of your fluid if it's been a ton of miles since changing fluid, but dropping the pan and replacing the 3 quarts that drain from the pan is safe. Use Dexron/Mercon III fluid. If you're ambitious, you can drop the pan and clean or replace the filter (screen).
 
I don't buy that. I had heard that line, but changed my hard worked F150 Lightning fluid after 85k miles and it was fine. New fluid has to be better than old. To me it's similar to the yarn about not using synthetic oil in a high mileage engine. By the way, I changed the tranny oil to synthetic with no problems.
 
I have never changed the transmission fluid since I got it, which was just under a couple of years ago. I know the previous owner took good care of it and before that it was a lease vehicle. If I had to guess I would say it has been changed at least twice maybe.
 
It is not total B.S. I have been an ase certified tech for about 10 years now and have been working in a GM shop for 7 of those years. In that time I have either done or seen at least 1,000 trans flushes or filter changes. Out of those I have seen 2 start slipping. Also, 1 wouldn't even move out of the shop after just a filter change. They had well over 100,000 miles on them and had never been changed. It is rare that it causes a problem, but speaking from personal experience working on vehicals for a profession, it is possible. If it was well taken care of, it should not be a problem. Either way I would change the filter and if the fluid is very dark, I would flush the fluid also.
 
hahaha yeah, flush it and move on, case CLOSED!
 
Don't they make transmission fluid for "high milage" vehicles that is a thicker viscosity?


I was under the impression that these "high mileage" fluids were partial synthetics.

Try the DexIII first. If it's a sweet ride, you're done. If it slips (very unlikely), try alternatives.

I'm in the middle of a long overdue drain/fill transfusion. I keep a sample of the pan drain in little tubes so I can monitor the progress from old, brown to new, red fluid.
 
I can see the reasoning behind the warning, but it's still total and complete BS. By that logic you could never change the fluid again so you are dooming your trans to fail no matter what. Get the flush, and if you have problems add some Lucas transmission additive, that will help your seals. I would rather change the fluid and risk slippage that can be fixed than run old transmission and wait for that time bomb to go off!!
 
While we are discussing filter changes, I want to do the change the filter in my 97. Somebody said that the TC has to be lowered to get the pan off. Is this correct?
 
I bought a 89 with an AW-4 and around 190k. When I drained the fluids it looked like the trans and diffs may never have been changed. I drained everything,and changed filter and (despite what everyone told me) refilled the trans with ATF+4. The theory was that the +4 is synthetic, slightly more frictionie (to coin a term) and should help to clean the surfaces a bit. I have four trips to RC and no slipping, also the fluid still looks clean and smells like new.

I dont recomend you did what I did but it worked so it is your call.
 
Having gone through this before, I can say that it is possible. Most, and I emphasize most shops that are out to do good business and not screw the customer won't touch an automatic if it's got over 100K on the orig. fluid.

My Step Dad's 04 Silverado was that 1 in 500 that dont react well. It had 123K on it when I changed the fluid and filter (did it twice cause I accidentally unplugged one of the solenoids taking the pan off and didn't realize it, so I actually more or less did a in house flush). About 1000 miles later the trans started slipping bad. Promptly drove it to the Toyota dealer and walked out with a brand new Tundra.

On the other hand, I changed the fluid and filter in my Jeep back at 90K and havent had a single problem. I plan to do mom's KJ here in the next month or so, once it warms up a little bit.

Bottom line, you'll be fine. The AW4 is a tough transmission...as long as you put the correct type of fluid back in, you'll be good.
 
While we are discussing filter changes, I want to do the change the filter in my 97. Somebody said that the TC has to be lowered to get the pan off. Is this correct?


Nope. It is kind of tight to get the pan off, but it will come out. Hardest part was getting the dip stick tube to come out with it.
 
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