I purchased my truck with 150,000 miles from someone who has no idea when the last auto tranny service was done. I have heard nasty rumors regarding flushing, draining fluid without regard to the mileage. I guess the question is, Should I just keep the old fluid and wait to rebuild? or should I go ahead and do the service?

If I should go ahead, should I flush or just drain? I hate to drive around knowing what might be slopping around in my pan. Thank you in advance for your responses.

Jay

 

i was told to leave mine alone, and my last serivice was 30 k ago when the tranny was rebuilt and the truck was stock. I was told to keep the old because w/e particles that wore out in the fluid helps to reduce slippage, but im on the fence bout it.

 

I think I would just drop the pan and change the screen a couple of times before I took it in for a flush. One thing I been comtemplating on the wifes durango is a external tranny filterin a cooler line. I think this would trap a lot of the junk in the trans. Summit Racing has a kit w hose for $30.

Jed

 

Drop the pan and see what you got first. If the pan is full of junk then it has not been changed. Just change the filter and replace what fluid you have drained. Drive it for 10K miles and then flush it.

 

I don't know why anyone would want to keep old dirty fluid in there. If there's gunk in there it seems to me that the valve body is going to get a lot of sludge in it and start sticking. If it were me I'd do a "half flush". Instead of back flushing it, drop the pan and change the filter, then put fresh fluid in. Then while somebody is in the driver seat, take the return line froom the cooler off and have someone start the truck and put it in neutral. When clean fluid comes out, shut it down and top the fluid off. Don't let more than a quart or two come out without shutting down and topping off so you don't run anything dry. This way you won't get the particles that I've heard people worry about floating around from doing a backflush. IMO there's no replacement for good clean pink tranny fluid. Makes me feel awfully good to pull the dipstick and see the nice color on there.

 

That applies to older tranny's mostly. There is an addative called trans-x I got at walmart and used it on an old 4.3 blazer. I canged the tranny fluid and filter and when I did, no reverse. So I added a bottle of that trans-x and it worked great. Just dont put bake fluid in the tranny if anyone tells you to. The myth behind that is it will help the seals swell and shift better. In reality it will eat rubber up! Check the fluid on the dip stick and smell it if it's burnt and dark I would change the filter only maby 3-4 times before I flush. And then start saving for a real tranny.

 

Id change it. Made a huge difference in my tranny. I guess it was ready for it.

Eric

 

Thanks for the responses guys. I guess the main reason for not doing it thus far is on account of my brother-in-law. He's a mechanic and tells me stories, scaring me to death. I simply do not have the $ to pour into the tranny now.

Does the main scare lie in the valve body? I just don't know what to do.

 

Don't know the facts behind it but have been told by several sources, some whom I respect immensely, that if the tranny fluid hasn't been changed for a very long time leave it be until something goes wrong. Changing really old oil will cause something to go wrong even sooner.

Friend bought in an early '70s model Chrysler station wagon with about 150k on it, wouldn't go out of first gear. I could tell by the paint that the tranny pan had never been removed. Dropped the pan, the fluid didn't look bad at all but the filter was totally plugged up. He didn't want to spend the money on a new filter so I just cleaned the old one and put it back in with three quarts of new ATF. That was at least ten years ago, he's still driving it around and the the last time the tranny was serviced was when I did it.