Is it REAL important to change mtx tranny fluid?

[DavidT]

I canot verify mine has ever been changed. Heck, how do you check the fluid level? Is it critical to the life of the tranny to change the fluid?

 

[sdpatt]

Actually, there is no fluid change interval specified in the owner's manual for the MTX. It will likely be to your gearbox's advantage to make sure that the fluid level is correct and the fluid is in good condition.

You check the level at the square-holed plug on the front face of the trans case. It is accessible from under the car and is about 2" to the side of the case ******. You can use a 3/8" socket extension with no sockets attached to remove it. The fluid level should be up to the hole when the car is level. Use a funnel and hose or a pump to get the fluid into the casing. You must use a suction pump and long curved tube to remove the existing fluid if desired.

My 1991 owner's manual specifies ATF Type F or Mercon II (now III) and I add a few ounces of Ford Friction Modifier to the fluid to improve the shift quality. Since manual transmissions don't generate the destructive heat like the ATXs do, the fluid has a very long lifetime and even if never changed, yours should still be very red in color.

 

[SilverSHO]

Is the Friction Modifier a dealer-only product, or can it be had at parts stores?

 

[fricker66]

The Motorcraft Fluid Friction Modifier is only a couple bucks at Ford. As I recall, I think it was $2.76. I'm sure there are other brands of the modifier that can be had at auto parts discount stores. However, it's a relatively cheap purchase to get the Motorcraft brand.

 

[smcallis]

There is a great product called smartblend made by Life Automotive Products. My F-150 had a drivetrain shudder when the torque converter tries to lock up. This stuff cures it.

 

[DavidT]

Thanks for the info! thumbs_u

 

[DavidT]

Can you check the level with the car on the ground? Or do you have to jack up the front and the back?

 

[drivinhard]

I would check/change once a year, it's easy to do with a drain plug and it's cheap insurance. With organic ATF, you'll notice a difference in shifting with a fluid changes in as little as 10,000 miles between intervals.

The quaife units tend to generate more heat than the stock diff, but you still run into heat soak problems in the summer-time, and also heat from the box itself. In the summer my 89 runs 190-200 degrees trans temp just hwy cruising. 250+ on the track. The stock units don't pull those kinda temps, but still probably run higher than you think. Install a drain plug, and change the fluid every 3rd or 4th oil change. Cost you less than 5 bucks and takes 5 mins.

You can check it with the front jacked up, just take into account that some will slosh to the back a little. If you are flushing/filling anyway, don't even mess with the level. Just put in 3 qts.