The truck is a 1989 F150 super cab LB, 2WD, 302 with AOD, recently purchased with 96k miles and in excellent overall condition.

My mechanic tells me the transmission fluid is dirty and should be changed, however, a mechanically-minded friend told me he wouldn't advise it as it appears never to have been changed (I have all the service records from the previous owners and it is never mentioned) since it could cause problems. Who is correct?

Also, there is a slight leak from the shift lever seal, is that a difficult fix, if not I might do it myself.

Any advice would be welcome!

 

you should change it today unless your friend will pay when your trans. stops working.

the fluid, filter and draining the convertor is what you need to do.

 

I would actually blow out all of the lines and flush the convertor too. If you have a transmission fluid cooler on it take it off and blow it out too. Tranny's are crazy expensive to fix, best to do incredible maintainence IMO.

bart

 

auto trans. love new fluid, over time the fluid loses some of its ability to do its job.

 

Thanks, it won't be this weekend! I need to read up and see if it is within my limited mechanical capabilities!! Would anyone be able to tell me if there are good instructions in either a Chilton's or Haynes manual. And by the way, which is the best manual to purchase.

 

I used to do it myself all the time. But now I've spent too much money on transmissions and don't ever want to here anything reguarding warranty coverage when I do the work... but just changing the fluid/filter/pan-gasket is a really straight forward task, though it can be a messy if your truck doesn't have a pan plug (and many vehicles don't). Either manual will probably have decent instructions. Personally I have chiltons, but that's only because that's what my dad uses. The one thing that will be more difficult to do yourself is flushing all the lines and the convertor. Basically, there still a lot of fluid left in the system after you've drained the fluid from the pan. This fluid is in your convertor, your lines to your cooler, and the cooler itself. Think about what the filter is filtering out... METAL flakes and worn clutch material that wear off from gear meshing together and clutching slipping together. This extra material can wear down your clutches faster then they should. So, by not flushing your system any extra material in the fluid still in the system gets mixed with and contaminates the fresh fluid. I've read articles on how to flush the system yourself, but it takes two people and sounds a bit beyond my comfort level. If you're up for it, have at it! If not, there's nothing wrong with finding a GOOD tranny shop.

One other thing that I like to do is put a magnet on the inside of the transmission fluid pan to collect the metal particles that get through the filter. Many transmissions come with these from the factory. You'de be surprised at how much metal they collect!

happy trails

bart

 

I recommend using mobil 1 synthetic mercon. Its awesome.

 

Thanks, I will invest in a manual and see if I can do it myself; and also get a price from a transmission shop.

 

They advise not to change fluid occasionally on vehicles with lots of miles due to the build of up old fluid on parts.
Changeing the fluid and the filter can break up this build up, and sometimes the transmissions stop working properly because they are relying on that build up.

This happened with my 85 tempo. I had to replace the transmission after an tranny oil change.
Vehicle stoped shifting properly.

There are arguments to both sides of the story.
Hands down however.
You do need to change fluid.
Athlough, waiting 96k miles is WAY to long to wait.
I'd change mine every 10k.
That might seem like a waste. but hell.
If walked that far, i think i'd want an oil change.