digbog

I've put about 20,000 miles on my truck since I have owned it. I wanted to change the trans fluid about 6 or 7000 miles ago so I took it to a very reputable local trans shop. I don't know what the previous owners maintenance practices were like and when I told them about it, they were a little leary about doing the work saying that the new fluids have heavy detergents in them. I was also told that this could cause some serious problems. He told me about one truck that he changed the fluid on. It drove onto the rack just fine and after the fluid and filter change the truck wouldn't move. It apparently had over 100,000 mi with no maintenance.
So.. What is the avg life span of trans fluid and filter? I don't want to be a FORD (found on road dead) so should I take the chance and have it changed?
Also... What does the fluid wash out? The TC or the whole trans? My truck currently has 129,216mi on it. Any advice would be great!

hamilton71801

My trans man told me the same thing. I took it to him with 120,000 miles on it with no previous history (I'm the 2nd owner) and he refused to changed the fluid saying just what you said. So I said Ok, and left it alone for a few months. The family and I had a big trip planned and I decided to do it myself...that was 36,000 ago and have done 1 more fluid/filter change since then. I understand what they are saying, but I took a chance and it all worked out for me. The question is, are you willing to throw the dice like I did?

fschiola

Did either of these transmission experts tell you what could possibly cause this to happen?

digbog

The exact quote was that "the detergents could wash the transmission out".
He went on to explain a little further in depth that it could require a rebuilt TC or new TC.

HOHN

This sounds pretty bogus to me.

What the tranny guy is trying to say is that the old unservice fluid has gunked up the trans and varnished the steels and glazed the clutches-- and that this gunk, varnish, and glaze is what is keeping the tranny working!

I'd not only change the tranny fluid, but I'd find a new trans shop.

If it makes you feel any better, find the cheapest crap for tranny fluid and use that, that way the gunk, varnish, and glaze that's keeping your tranny functional will be safe

hamilton71801

This may just be an old trans shop wives tale, but I have no reason not to believe my guy. He is the most trusted shop in town and is a close friend's dad who has serviced thousands of transmissions. His observations could all be coincidence but I value his advice and his experiences. I took a chance because I knew that if it broke, I would be one step closer to a built trans and my wife really couldn't stop me from getting it...well, I guess she could stop me but I would have a good excuse.

Anyway, he told me not to touch it unless the fluid was burnt or I was having problems. The only problem I was having was I can't seem to leave anything alone and just had to try for that Goerend. I'll get one sooner or later.