My 86 GT has had a major overhaul by me over the last few months but I would still like to do the transmission fluid and the filter. My question is how hard it is to do myself ??? Keep in mind I am not the best and I will be asking for help if I get stuck. I read the service manual, basically it said -- take off the pan, drain the fluid, replace the filter, rebolt the pan back and fill. Is it that simple or am I missing something ???
Just be prepared for potential problems. It may be working fine now, even though theres some wear. Putting in all new fluid may be asking for disaster. I actually know people who drain the fluid and save it, put in a new filter and reinstall the old fluid just to avoid problems. A clogged filter will reduce the oil flow. A new filter can remedy that without putting new fluid in that will flush out all the residue that is what is keeping it working. I normally dont ever touch an auto trans till it quits. I normally get 200k on my cars before I trade them without ever touching the trans. I had problems in the old days with every trans I ever changed fluid in.
It's that simple conceptually. Getting the pan down is kind of a pain, and quite messy, because its full of fluid as you pull it down.
I 'd recommend new fluid, old fluid oxidizes and breaks down over time and with heat. I've never had a problem with new fluid causing problems in old transmissions (including a 89 Beretta with the same TH-125C transmission).
A friend of mine works for a transmission shop. And swears by a backflush cleanout compared to a filter fluid changes esp if it has high miles and hasn't been changes before... as he stated the trans is worn in to the reduced fluid pressure. And fluid consitency already inside . When changing a filter and putting new fluid in it. It can blow worn internal seals bc of the higher flow rate. And the new fluid can seep in places the old wouldnt due to the new additives.... who knows if this is true? If someone else can chime in it would be great... but I honestly believe him.. bc reguardless which route I chose it would cost me about the same. And I don't think he would steer me wrong
Lots of people never change fluid and drive their cars without problems. Smell the fluid and if it smells burnt, then you should change it. If it is reddish and clear, you probably do not have to change it. A lot depends upon how the car was driven.
I decided that it is better to change it because dirty fluids has bits of metal in it and those bits of metal are not doing anything good for the transmission. Changing it yourself is a mess because you have to drop the pan and the fluid comes gushing out. I have done it a few times but now I take it to a shop and let them do it. The local transmission shop changes fluid and filter for about $80. If you change it yourself, you will need between 4 to 6 quarts of Dextron fluid (about $6/quart) plus a new fliter (about $10 to $15) or at least $40 for fluid and filter. So you will not save much money doing it yourself.
Before changing the fluid read a Haynes Manual on page 53 which describes the procedure and you might change your mind about doing it yourself.
If you think you want to try to replace the trans fluid yourself, here's a tip. Buy a pump like this:
These things cost $10-$15 depending on where you buy it. Use the small diameter tube on the inlet side of the pump and stick that small tube down the trans dipstick tube. you should be able to get that small tube all the way down to the pan in the trans. Pump until there is no more fluid coming out. Then you can pull the pan without having fluid come gushing out. But even with pumping the majority of fluid out of the pan, you should still just loosen all the trans pan perimeter bolts (don't take them out) and then use a pry tool to pull the pan away from the gasket/trans. Once you have done this, you can put a floorjack up to the pan (put a short 2x4 on the jack to spread the load and keep the pan balanced). Then remove all the bolts, lower the jack and you will have the trans pan with a small amount of fluid in it. No big mess.
[This message has been edited by lateFormula (edited 07-14-2013).]
couldn't you just disconnect the cooling lines and put the output line into a 5 gallon bucket and the inlet line into a gallon of New fluid. start the car , changing out when the new fluid runs out. ( think they hold about 3 gallons w/ converter) do it until it's clean ? that way you get All of it. just a theory. (then change the filter). I have changed the fluid in about 15 cars in my lifetime, never had a problem stemming from a fluid change.
Be sure to wear rubber gloves and the tranny filter is pressed on, so wiggle it off. Don't forget to clean the crud out of the bottom of the pan. I usually let one side drop down slightly lower than the other, to get as much fluid out as possible.