Is it true that it is not wise to change your tranny fluid when you have high miles. I have 140k on my 2000 p38 4.6. I've heard horror stories on how soon after changing the tranny fluid the tranny developed problems. Thanks the RR gods I have had no problems with my tranny, but I was considering a flush and fill or just maybe a change of the tranny fluid. What do you guys think.

 

If no flush has been done yet, and you have no issues, I would definitely not flush it out.

Power flushing cleans off the seals and gaskets, and everything else, and then the detergents attack the worn parts and gaskets. Leaks --> low fluid REAL fast --> slipping gears --> destroy a clutch pack.

I saw a Firebird once with 120k, flushed the tranny, and was back in for a tranny rebuild in 1500 miles.

Your best bet is to check your fluid level, and add some high mileage formula fluid to top off. I did see somewhere that it was relatively safe to just change out the filter. Just removing the pan, new filter in, and replace fluid with high milage (no flushing). Ill see if I can find the post explaining that. Or Disco Mike will pop up here in a sec.