Hi. Im a new when it comes to engines and cars but I'm trying to learn as much as I can. Anyways i recently aquired a 91 Rx-7. I'm pretty sure the transmission fluid needs to be replaced, but my friend, who is a technician suggested that changing the fluid could cause the transmission to wear out faster, due to the fact that the fluid is so old? Is this true, and would it be ok to replace my transmission fluid? Or should I just wait and not change it and wait till my tranny fails?

 

Um wow I think not doing it could possibly be the worst thing you could do...

 

Put a good synthetic gear oil in your car. Do a search and download the FSM to get other ideas about maintenance on our cars.

 

Your friend is a bad technician..
Definitely change the fluid.

 

Do you have a manual or an automatic transmission?

The tech is talking about an automatic and everyone on this thread is talking about a manual. It is a general rule for Technicians that if the automatic transmission fluid has not been changed within 100,000 miles then it should not be Flushed at all. With really old fluid there is a risk of a "No Go" or poor shifting as a result of the newer oil being thinner. No shop wants to be responsible for this happening. A filter change with just the oil in the pan is generally OK since it is only about a third of the total fluid. There are no issues like this on a manual transmission unless you put the wrong fluid in it.

Several people put Royal Purple 75W-90 in theres. I put Redline MTL in mine because I found it for $2.50 a bottle.

 

Houpty hit the proverbial nail on the head with his post. If you happen to have a manual you'll need to fashion yourself one of these:

It's basically a 3/4 heater hose with a gear oil nozzle taped to end. It makes filling the transmission easy and relatively mess free.

You can find the fluid capacities in the factory service manual which is in the FAQ.

 

yes its an auto . Now it makes sense. Ty

 

eww you wanna change the whole tranny not the fluid. lol. sorry those slush boxes suck a guy around here had a 25 na with an auto and it did like 17.3 1/4 mile runs with my identically modded s4 5 speed ran 15.2, a huge difference considering he has more base hp. honestly i'd go to the FS section and look for trannys

 

well im not really good at driving at manual yet. maybe one day.

 

OR you can use an oil bottle, plug a clear* line into the bottom of the bottle and put an air line in the top, then pressurize it to fill your trans. IIRC, a quart sized bottle might hold around 8psi without bursting. I used a 4 quart bottle and it seemed to be near the breaking point at maybe only 1 or 2 psi, so the oil moved slow but I found other things to work on while I waited. I have a picture or two but my camera is in my garage.

 

you don't get good until you start to drive one every day

 

I take it this is an automatic based on other posts in this thread?

In that case, the fluid should not just be changed, but the transmission should be flushed. Any competent transmission shop can do this for you. As the fluid gets old, it's more likely to cause slip which causes heat, wearing it out even faster. You may find that after a fluid change the transmission performs much better and may not need to be rebuilt for many miles.

 

Wtf? That so called technician is a joke, thats like saying don't change your oil every 3000 miles or 3 months, just leave it in there til the motor blows up then buy a new one

Do yourself a favor go to AAMCO or Mr Transmission or whatevers near you, basically a good tranny shop...get um to flush the thing out and use some high quality ATF.

 

Have you read this thread? It's and automatic even many tranny shop advise againts changing fluid if it's been in there a really long time

 

Don't rip on others that know what they're talking about. You should try using correct spelling and write in complete sentences.

Old fluid is old fluid; it should be changed every 30k (at least every 50k) miles. Almost every shop that sells transmission flushes doesn't change the trans filter, they just hook up the lines and change the fluid.
You can flush the trans at home by changing the fluid and filter, then running it for a while and changing the fluid again. That will flush out the quart of old fluid in the torque converter that doesn't drain out.

 

im saying that the transmission oil does not look like it has been changed for a long time. it will take out the old grimy oil and sludge, but since it hasnt been changed, that might be at a disadvantage. bleh if that doesnt make sense im sorry, i cant really explain that well.

 

Thats funny because totalimmortal you didn't even read what I said did you? I said take it to a tranny shop and get it flushed. Which is exactly what is needed to be done. Maybe before trying to shut me down you should know what your talking about in the first place.

 

ya, uh, electric, shoosh. and with aaron cake and houpty, yes, your friend is right. unless it hasnt been changed in a while, there is a chance with it not working afterwards. happened to me when i worked at toyota as a tech, same thing, changed tranny fluid, then we replaced the ladies tranny. not fun =(
good luck excel, at least you are asking good questions. use the search key too, you might find other stuff that you didnt think to ask about!

peace

 

then swap it to a manual transmission haha

 

dunno if its too late but Ive got the same prob.. so I just changed my transmission oil.. guess what.. it didn't do much good, dont get me wrong its better but still rough when shifting.. so I put in Slick50 transmission oil.. the 80ml litre bottle.. and after 5 minutes of driving its good as new.. trust me on this I just did it today and been driving for about 50 kms.. try it.. thats all I can say