True or False 94 Auto Trans question....

[Cheddar Dan]

My nicely working auto transmission has 65k miles on it and has never had the fluid/filter changed or any service whatsoever.
There is a rumor that changing transmission fluid and filter at this late date could bring on problems. Does anyone have the facts on this to share??? Is it ever too late to service a working auto trans??

Thanks in advance!
CD

1994 Explorer XLT 4DR Auto 4x4

 

[92exp4x4]

No. New fluid will not kill a trans. I bought a 97 F250 with 214,000 on it. First thing I did was change the trans fluid, it looked like coffee. The trans shifted a little hard but never slipped. Its been going strong and shifting much better for almost 10,000 miles now and thats with a loaded trailer behind it most of the time. BTW, got a great deal on it too, the guy thought the trans was going out of it.

Ford recommends servicing the A4LD every 30,000 miles. On a high mileage trans, the new fluid can losen deposits that fill wear marks in bores and such inside the trans and valvebody. Transmission fluid is like 60% detergents, so new fluid will clean all that crap out. When the dirt is gone and the tolerences open up the trans may go "bad" but in reality it was worn out to begin with the only thing holding it together was build up in the trans.

If you change your fluid and the trans pukes, it was on its last leg anyway. Don't be scared to service your trans, most likely you will get many more miles out of it especially if its been rebuilt before.

 

[Jason94sport]

All I know is my A4LD died in 2 94's about 20K miles after changing the original fluid & filter.
Luck? IDK...

 

[Roadrunner777]

Back in the 70's there was an issue where people were changing from non-detergent oil to the newer detergent oils. The problem was that the detergent additive tended to wash away deposits that were helping to seat the piston rings. So, changing to detergent oil caused engines to start burning oil.

I think people try to apply the same theory to AT fluid. They have run the fluid far beyond it's useful lifespan, and the additives are long used up. So, running new fluid introduces new detergents, potentially washing away deposits that at that point, happen to make the trans work correctly.

To your point: Well, what is normal fluid change interval? 50,000? I don't have that handy, but 65k is not far overdue for AT fluid. In your case I would do it.

Now, I tried to address the same question last summer. What I ended up doing was sucking out 2 quarts through the dipstick tube, and putting 2 new quarts in. I did this weekly until my math said I was at 75% new fluid. (it is a bit of a math challenge because you have to work out the dilution of the new fluid in the old. It took something like 10 quarts.) Next summer I will drop the pan, change the filter and adjust the bands.

By the way, the correct fluid is Mercon (just plain old Mercon) which appears to be a dealership item now, or Mercon V, which is the official replacement, or Mobile 1 ATF.