1991 Ford Explorer M50D Manual, changed fluid now reverse is bad

[Sbeghan]

Hi guys, I just changed the fluid in my explorer and am now having issues with reverse.
I drained it last night, looked reddish-black. Today I put in a bit less than 3 quarts of valvoline maxlife synthetic atf dex/merc / merc V through the fill hole. I couldn't get it into reverse, and the gears feel more crunchy. I drove around town for 15 minutes and started to be able to get it into reverse intemittently, sometimes without a problem, sometimes with a loud crunching.
Is this going to get better as the fluid and transmission learn to get along, or should I change it out with non-synthetic dex/merc that says "not for use with merc V"?

 

[acschilling]

I'm not sure about the type of tranny fluid you have used though it sounds okay...did you take a look at clutch fluid levels?

 

[FR-425]

http://cdn.lrsstatic.com/downloads/tsb05-14/tsb06-26-01.pdf

 

[RangerX]

I don't recall how much it holds, did you fill it to the top of the fill hole?

 

[4x4junkie]

Dex/Merc is the fluid to use in a M5OD (holds just a bit shy of 3 quarts)
I've seen Merc V affect the shifting quality of the trans, though usually not quite to the extent you're describing (and not just reverse while the others are fine). Possible you got another (separate) issue going on with it.

I've also heard good reports from a few guys using 0w-30 synthetic motor oil in the trans, though I have no personal experience with 0W-30.

 

[Sbeghan]

I filled till it started to come out of the fill hole. I didn't touch the clutch fluid (except to suck out what was accessible in the reservoir and top off with fresh fluid, since I was also doing the brakes).

I could have another issue, but the only thing I did to the trans was change the fluid out.

I'll drive around a bit tomorrow and see if there's any improvement, if not I'll try some cheap dex/merc, and then the 0w30. Pity I already disposed of the old fluid!

 

[4x4junkie]

Eh, you don't want to put that old crap back in lol.

I wouldn't drive it around though, I'd just change it. Once a M5OD has seen Merc V, my experience has been it doesn't seem to ever fully recover (my best guess is it must permeate into the brass of the syncros, it's just too slippery for them). Maybe if you catch it in time it's effect won't be so great, it's worth a shot at least.


If you want to flush the clutch fluid (advisable), you have to do it from the bleeder on your slave cylinder (I did this when I got my BII in '04... the fluid that came out was NASTY!!! (guessing it was the whole 14 years old) Took almost half a 1-qt bottle of Dot-3 before it started coming out clear. YMMV).


Edit:
It just occurred to me after I had posted, any chance you or someone bumped or pressed the clutch pedal while the fluid was sucked out the reservoir? Maybe that could be your issue... (air was allowed into the system) Is the clutch releasing just barely up off the floor now?

 

[Sbeghan]

I haven't bled the clutch fluid, though I should. I need to figure out where the bleeder is first, haha.

I changed the transmission fluid out with noname Dex/Merc and its working much better now. Usually goes into reverse now! I think it needs some more time for the fluid to work its way in there and it may never be the same after putting in Mercon V.

 

[Sbeghan]

double post