Should Manual Transmission Oil Be Changed?

[blkfordsedan]

Glad to hear your trans is still shifting good, John. Synchromesh is good stuff. Its not old school gear oil, but was designed by GM (IIRC) specifically as for manual transmissions. It is still thin enough for proper lubrication and cold temp shifting, but also provides the proper gear protection and friction for synchros that ATF does not. I have read that it is basically a 5W-30 oil with EP additives and friction modifiers. If you experience cold shift issues you can try the Redline MTL or ATF4. If not, just stick to what you have.

[Movin]

35 years ago the secret to a smooth shifting mustang was a tech sneaking
GM syncromesh into the dealership and getting the empties back out.

The do it yourselfers that came in and bought there own oil were screwed!

This was told me in the late 80's when I started at a dealership and couldn't
get the chunk out of a new mustang until I was pulled aside and told this little
secret....

So much for college training!! Experience will always trump specs and books.
sometimes they are in concert, but too often not.

You are in the right place...

[getnpsi]

Who else has had a contamination or lubrication issue in their e-series transmission regardless of the fill?

Movin: My 1990 ford tempo had GM seatbelts. You could not see until the plastic around them broke down the seam. They were navy blue with grey interior too BTW. The button didnt say GM on it like the late 70s early 80s GM's but there are tags on the canvas part. Dont believe me? Go to pickapart and find a tempo and see for yourself. Crazy huh.

[AlaskaFestivaGuy]

I think my old Fiat had a magnet built into the gearbox drain plug so that any ferrous material came out with the plug and could be examined.

[Pgh5spd]

My '88LX, in the family since new, had light gear oil in the gearbox. The '88L I bought with 50K original miles a decade or so ago and that had received a bare minimum of maintenance may also have had light gear lube (can't recall for sure), but the 5-spd that went into it got ATF and then my daughter drove the piss out of it for years with no trouble. That transmission came from a '91L that I drove for a year or so. When I first got that one I noticed that the trans had a whine at speed, which was due to barely having a quart of fluid in it thanks to leaky halfshaft seals. Changing the seals and filling the gearbox solved the whine and then I drove that one for another ~6K without problem until it donated its trans to the '88L. My '93L bought with 83K 9yrs ago and also minimally maintained had AFT. When I popped a halfshaft to replace the boot, the fluid had that silvery look so I put new in. When I did the other side a year later, it looked silvery again, but it shifted fine and I just put it back in. No shifting issues over maybe 50K mi until I sidelined it for tinworm issues this summer. Now my nice '90L, bought this summer with 77K, has ATF. I have reason to suspect that even the rotors on that one have been original, so the fluid ought to be original, too, particularly since, as hard as the speedo gear was to get out, I doubt that it had ever been removed since the factory. The only issues I've ever had with shifting were that after maybe 10yrs the '88LX would shift hard in the dead of winter till it warmed up. I think I may have replaced it with ATF for the last couple yrs I drove it, and that may have cured it, but it's been too long ago to remember. In any event, the hard-shifting temps only last a few wks here so it wasn't a big issue. I've never had hard-shifting issues in winter with ATF-filled transmissions.

[JohnGunn]

I've never had hard-shifting issues in winter with ATF-filled transmissions.

I appreciate your giving us the benefit of your extensive experience with Festiva manual transmissions. All I can say is that my experience, documented in various threads on this site, has been much worse than yours.

I've owned only two of these cars, 1990 Festiva L with 66,000 miles and my current 1994 Aspire bought with 75,000 miles. In both cases, when I test drove them for a short period of time, I didn't notice any problem with the shifting. Maybe if I had just left the gray fluid that was in them alone, all would have been well. But my inclination when dealing with a new-used car is to start by replacing all the fluids. For most things I think this is an advisable plan, but when it comes to the manual transmissions in these cars, there is some serious doubt about what was used in the original fill.

The Ford manuals recommend ATF, although strangely enough they do not specify any change interval, so I felt safe in draining the old fluid and replacing it with ATF. In both cases I noticed a decided harshness in the shifting after that change and it only got better when I switched to gear oil. The Festiva still had consistent synchornization problems for the full 16 years that I drove it. And I assume the Aspire would have been plagued in the same manner had blkfordsedan not told me about Penzoil Synchromesh which brought the Aspire shifting back to a mostly smooth, acceptable level.

This has been my experience. It has not been yours. I don't know how to explain that. For anyone who buys a new-used Festiva/Aspire and feels as I do that it is necessary to change the transmission fluid, I would say, just to be safe, save the old fluid. If you want to use ATF, use it. If it works for you, consider yourself lucky and go on with your life. If, however, your experience comports with mine, filter the old fluid and put it back in and see if the performance improves. Or, what I would suggest from the beginning, use a fill of ATF just as a very short term flush, and go to Penzoil or Red Line MTL, which I plan to test in the not too distant future.

And to anyone with shifting problems which a new fill of ATF fails to address, consider the new ATF fluid to be a flush in preparation for the Penzoil, before giving up and going for a rebuilt or used transmission.

Of course, there is a lot more to be said on the subject, for example to ask what Mazda recommended for these transmissions when sold in models of their own brand. Hint, not ATF.

You will find a lot more information should you read the whole of this thread, giving special attention to everything blkfordsedan has to say on the subject.

And my best wish for you? Continued good fortune.

[FeistyFesti]

John I've used Redline ATF D4 in all my Ford manual trannies and they've always performed flawlessly. Redline's film strength is very tough so it makes shifting smooth yet provides plenty of protection against wear. I've owned two Fox body 5.0 with T 5s and a 90 Taurus SHO and always switched to Redline ATF D4 after I bought the cars.

[koRnhead]

We get it john. Really we do.......you like to do things your way. Which is fantastic. Good for you......other people like to do things their way. Fantastic for them!
We are all glad your tranny shifts great. But please stop preaching about how your way is the only way.

[Jim Rockford]

Changed mine tonight, no by choice, I replaced a cv axle and most of mine drained out,so in went dextron, drove it about 10 miles on the backroads with lots of shifting, No different than before and no noise .

[Pgh5spd]

Ha! You beat me to it, Jim. I thought while working my way down to the newest post that the manual ought to say change the fluid when replacing the CV boot or halfshaft seal, whichever needs occurs first.