M5R1 Trans Reassembly and Lube

[vanmor]

Got all my parts in today to reassemble my M5R1.

My stepdad asked why can't you use motoroil for lube in these transmissions. Something like 5w or 0w. I have read that you can't use Mercon and that you can. I heard you can only use Dextron. Then some people use like B&M Trickshift synthetic.

What can I use for lube in my 91' M5R1 Ranger 2.3 ?

 

[4x4junkie]

A few guys here have been using 0w-30 synthetic motor oil in the M5OD without issue.

Mercon is the fluid specified by Ford for it, so if someone said you can't use Mercon, never ever take advice from that person again (unless it was Mercon V that you read, and you left the "V" out of your post... Yes, Mercon V has been shown to negatively affect the quality of shifting. All M5ODs thru '07 spec Mercon (not Mercon V) to be used).

Mercon (aka DextronIII/Mercon) is usually labeled "Dex/Merc" these days, so look for that on the label (it'll say on the bottle it's for Mercon applications)

 

[vanmor]

4X4junkie,

Your right, it was Mercon V that was listed and said NOT to use.

I read a post somewhere that said use Mercon or Dextron and change every 12,000 miles. We're talking what, a quart and a half ? I think thats wise advice.

Thanks for the info.

 

[HareRazor]

I believe they take a smudge over 3 quarts to fill completely.

 

[racsan]

i have ran pennzoil syncromesh fluid in mine before without any problems. its not a synthetic though. about a year ago i switched to mobil 1 0w-30 full synthetic motor oil.

 

[AllanD]

It's actually a smidge UNDER 3quarts.
Spec is 2.75quarts.

But if you simply fill it level with the fill plug it's almost exactly 3quarts.

As for what fluid? I'd recommend against engine oil, if you run engine oil it goes "funny"
fairly quickly... it isn't mformulated for the Shearing action that transmissions generate.

B&M trick shift? should be fine.

and it's distinctive blue color will tell you that any red puddles aren't yours....
an important thing to know

AD

 

[pcollins]

wait, i was told by someone on here that Mercon V IS what i should use...is it destryoing my transmission being in there? or can it wait a little while before i change it to something else? i don't mean to thread jack but i just read that and kind of panicked...seeing as my daily work commute is 70 miles a day.

 

[Sasquatch_Ryda]

There have been reports of shifting concerns when running mercon V in the earlier M5OD's.

It won't wreck anything, if its not causing you any issues, don't be too concerned. Ford says it is fine to run Mercon V in them now as they have phased out regular Mercon.

 

[4x4junkie]

My buddy's truck I think ended up with Mercon V in it at some point from one of those "quick-change" oil places. It seems the synchros never did fully recover from it, it continues to be a little stiff or "notchy" even after putting straight Mercon back in it. Take it for what it's worth (the truck does have about 170K IIRC, I s'pose it's possible they may just be worn too).

Mercon V will not damage any of the hard parts though (gears, bearings, etc.).

 

[DPDISXR4Ti]

A few guys here have been using 0w-30 synthetic motor oil in the M5OD without issue.

Bumping this old thread as it's the only one I found in here that mentions using 0W-30 synthetic motor oil in the M5R1. I've used this in my '91 F-150's M5R2 for years without issue. In fact when I made that decision I found a factory document which recommended it (can't find it now).

Any way, just wanted to confirm it as a viable alternative, from my own experience. It's what I'll be putting in the M5R1 that I currently have on the garage floor which will be going in the '89 Ranger.

On a related side note, can someone confirm that you can fill from the shifter hole? I'm pretty sure that's what I've done before.

 

[PetroleumJunkie412]

Bumping this old thread as it's the only one I found in here that mentions using 0W-30 synthetic motor oil in the M5R1. I've used this in my '91 F-150's M5R2 for years without issue. In fact when I made that decision I found a factory document which recommended it (can't find it now).

Any way, just wanted to confirm it as a viable alternative, from my own experience. It's what I'll be putting in the M5R1 that I currently have on the garage floor which will be going in the '89 Ranger.

On a related side note, can someone confirm that you can fill from the shifter hole? I'm pretty sure that's what I've done before.

Hey, good to finally see ya over here!

Have filled from shifter hole on FM146. Never tried it on the M5

 

[Shran]

You can definitely fill it through the shifter hole.

 

[Snoranger]

Bumping this old thread as it's the only one I found in here that mentions using 0W-30 synthetic motor oil in the M5R1. I've used this in my '91 F-150's M5R2 for years without issue. In fact when I made that decision I found a factory document which recommended it (can't find it now).

Any way, just wanted to confirm it as a viable alternative, from my own experience. It's what I'll be putting in the M5R1 that I currently have on the garage floor which will be going in the '89 Ranger.

On a related side note, can someone confirm that you can fill from the shifter hole? I'm pretty sure that's what I've done before.

I can’t promise you that 0W-30 will work in your M5OD. I can tell you I’ve used it in one of my own without issues.... I’ve also used Mercon, Mercon V, Syncromesh, 30w non-detergent engine oil, and Transynd.
Yes, you can fill it through the shifter. Just pull the fill plug, pour it in the shifter hole until it runs out the fill hole. Easiest way to fill one.
I see you’re friends with PJ412... I’m sorry.

 

[DPDISXR4Ti]

You can definitely fill it through the shifter hole.

Great, thanks for the confirmation.

 

[DPDISXR4Ti]

Picked up a 5 qt jug of synthetic 5W-20 yesterday. I figure I'll be the guinea pig in testing that one in the M5.