This is a common topic on
www.coutour.org
There are lots of alternatives for the MTX-75 trans.
Factory fill until part way into the 2000 model year was Mercon.
Someone discovered that adding 2 oz of Ford friction modifier to the stock fluid made a big difference in overall shift quality and that became a common addition (it really works quite well).
Several started using Mobil 1 ATF which is a full synthetic with Mercon Spec and adding Ford friction modifier. Many were very happy with that.
A few have used Mercon V (which is a semi synthetic), with and without friction modifier. Reports were good on that too, especially with the friction modifier added.
Someone tried the Chrysler spec ATF+3 dino fluid and many have reported that this fluid provides the best overall shift quality of any of the fluids. No additional friction modifier is needed as it has a higher level to begin with.
A few have tried ATF+4 and report that it works as well or better than ATF+3. ATF+4 is a semi synthetic. Both ATF+3 and ATF+4 are used in some Chrysler manual transmissions.
Terry Haines, a former Ford powertrain engineer that was involved with development of the Mondeo (Contour) and now owns a specialty shop in the Grand Rapids area of Michigan (probably the most knowledable person there is on that trans) likes the Ford honey fluid best, with friction modifier added. He reports that on teardown he finds virtually no wear when that fluid is used. Ford honey is a GL-4 gear oil, 75w90 IIRC.
There is also a loyal following that have used Redline MTL. MTL is a GL-4 fluid. They report that no additional friction modifier is needed.
Redline also makes an ATF type fluid that many have used instead of Mobil 1. MT90. Those that use it say that added friction modifier is recommended.
Receintly a few have tried GM Synchro (Synchroshift or Synchromesh, I don't remember which) and report that it works well. It is a dino fluid. I don't know if they have been adding friction modifier.
Penzoil is the supplier for GM Synchro. The Penzoil fluid is available in both dino and synthetic. There is an unconfirmed rumor that the Ford Honey is relabeled Penzoil synthetic.
There may be more, but that is what I remember off the top of my head.
I have used Mercon, ATF+3, and Ford Honey with added friction modifier in my 98 Contour SVT. As far as overall shift quality is concerned, the ATF+3 and the Ford Honey with friction modifier operate just about the same with maybe a very slight edge toward the Ford Honey. I have three bottles of ATF+4 on the shelf for the next time I change fluid.
From the reports back on Redline MTL you should be just fine with it. It may easily be the best bang for the buck for synthetic GL-4 fluid for that trans.
The best bang for the buck on dino ATF would be ATF+3.
It is interesting that the fluid for this trans was originally dino ATF and that it later changed to synthetic GL-4, with the recommendation that the GL-4 could be backfitted for both drain and refill as well as top off.
Are you confused yet?
Has anyone found an alternative to the Ford specified fluid (XT-M5-QS) for the MTX-75 manual transmission? I have been running Redline D4 ATF as it met the specs for the fluid the QS superseded and it has served me well. However, I am always open to suggestions and want to make sure I am running the best product I can. Althought my owners manual suggests the old ATF, my car actually came equipped with the QS; the fluid was honey color when I drained it. I was not overly impressed with the performance of the fluid, finding it much harder to shift than the D4. Of note, I take the car to HPDE's, will be fitting a Torsen helical ATBD in the near future and rev-match on downshifts so as to be as kind as possible to the gearbox however I do drive in a spirited fashion. The 8.5lb aluminum flywheel I have means that I have most likely reduced the load on the transmission significantly.
