what geal oil should i use ?

[MailManMike]

i have a 89'mtx and i just did a transmission job and was wondering what the best gear oil there was to use ? i heard b&m trick shift is good . thanks-

 

[sdpatt]

The owner's manual specifies Type F ATF and the later version MTXs also specified MERCON II (now III). I have had excellent service and performance from the Type F and a shot of Ford Friction Modifier.

 

[shobikes]

Scott,

What does the friction modifier do? Does it make the ATF a little slicker - better adhesion?

 

[shojuan]

shobikes:
Scott,

What does the friction modifier do? Does it make the ATF a little slicker - better adhesion?

Hehe, it makes the type F work better in our tranny than it would by itself. Exactly what the Ford modifier does Scott or somebody else can answer.

FWIW keep in mind that different materials were used in the construction of sychros depending on whether you have a very early car (which you do) or a later model. Early models such as our 89's use brass synchros. Later models (91 on up?) use fiber lined synchro blocking rings. It's my feeling that the fiber lined syncros work optimally with a lower coefficient of friction fluid (because the fiber material has a higher coefficient of friction than brass). Therefore keep in mind that what's best for later trannys (or early trannys that have been rebuilt with the fiber lined blocking rings) might not be best for original, early SHO trannys.

From my experience the original factory fill worked pretty well, Redline D4 worked really crappy, and a mixture of roughly 50/50 Redline D4 to Redline MTL works great in my 89 (which has all original internal parts). That fluid mix I'm using now works better than the factory fill I feel. 100% Redline MTL would probably be an appropriate fluid for the brass lined syncro SHO trannys (although I've never tried 100% MTL. Just the mix I'm using). Others have found MTL to be a good fluid for the 89. DON'T try 100% Redline D4 in the 89 tranny. Too slippery for those brass syncros to work.

Or try motorcraft type F (and if you don't like it straight then add some Ford friction modifier). Or try GM syncromesh.

All I know is I'm happy enough with the shifting performance I have on my tired old SHO at the moment that I'm in no hurry to install the rod shifter that I have sitting in my garage. My cable shifter, warts and all, with a good fluid in the tranny isn't so bad.

 

[shojuan]

OK, forgive me. I didn't read that you just did "a transmission job". Assuming you installed new style fiber lined blocking rings you might want to ignore my suggestion that you try Redline MTL and avoid Redline D4. The GM Synromesh or Scott's recommendation would be fair game to try as well. Go for what "feels" right when you try it. I don't think component longevity will be maximized if the fluid you are using doesn't feel right. But I think that any of these fluids have the potential to give long component service life once you meet the criteria of "does it shift smoothly".

 

[SHOForum Admin.]

Type F ATF is good like Scott said. Trick shift, Redline or GM synchromesh are also other alternatives that are of excellent quality and perform quite nicely in our transmissions.

 

[masho95]

shojuan
Early models such as our 89's use brass synchros. Later models (91 on up?) use fiber lined synchro blocking rings. [/QB]

Never hear of a brass synchro. I know you are talking about the blocking rings, but your posts go back and forth with the naming of them. As far as "gear oil" is concerned it's should never be used in the SHO tranny. Type F or Mercon/Dexron Type III is recommended for our trannies. I've had experience from Trick Shift to Mobil 1 synthetic/non-synthetic. I'd actually perfer the Mobil 1 non-synthetic over the others, but I've yet to try the Redline series. But it all comes down to personal preference. Some people swear by one brand and others swear by another.