Seems I hear a lot about trouble with this tranny. My clutch was just redone and the old one was very bad. Now I have no problem shifting into gear from dead stop when hot, but get grind on 1-2 shift unless I wait or raise RPMs like clutchless shifting. Better when hot. Come chunkiness in 2-3 and 3-4 shifts too. I am running 20w50 motor oil and noticed when I went from 10w40 to the 20w50 the 1-2 shift worsened. I think it is time to get rid of the 20w50 as it is too thick. Question is do I go with ATF or 10w40 (which the dealer said I could run in there). I am leary of ATF in a manual tranny. Here is what I found on the net: Popular Mechanics Q&As re ATF in Ford pickup with 5 speed manual said not under any circumstances to run anything but the recommended ATF as the clearances, surface hardness, and shift efforts are set up for the lighter viscosity lube. Otherwise you will have a hard-shifting, short-lived tranny. However, I found a mechanic's post re ATF in manuals saying ATF gives the manufacturer better gas mileage bragging rights but does the tranny no favors. He recommends 10w40 (straight 40 in hot climates). Then I found a post from FTE in 1997 that said the transmission (5 speed) has a tendency to "grind" a little on the 1-2 shift, but generally no problem on the 2-1 shift, and worse when cold (sounds like my problem). This person says a Ford dealer told them this is "COMMON" and not a problem in the MAZDA manual transmissions. Oh boy! Just what I suspected--the thing apparently is a piece of junk! Anyway, I see a lot of recommendation for "Red Line" lubricants including ATF for manual trannys. Anybody have experience with this.

 

Ive used Mobil 1 Atf in my M5OD from day one , its now 10 yrs old & knock on wood , has offered me zero problems . I switched to the Mobil 1 after repairing some minor leaks , not enough RTV was used on some parts . I also noticed it harder to shift into 1st after I changed the clutch in my truck . The only thing I can come with is that I had the flywheel resurfaced & even though not a lot of the original surface area was removed , I think it is just enough to not allow the clutch to fully disengage ? I think if I had it to do over , I would either leave the flywheel , as long as it wasnt scored or had excessive heat damage , as is or buy a new one . Try the synthetic trans fluid , it sure wont hurt anything .

 

I've used the Redline MTL in other vehicles that suggest using 75W90 and 10W40 with some negative results.

In my car that requires 75W90, the redline worked very well and seemed to be the same in viscosity. Now it has 40K miles on it and no change in shift effort and no additional noticed damage.

In my car that requires 10W40, the redline is substantially thicker and made the shifts smoother, but was obviously a drag on the engine when cold. That car now gets Honda MTF which is a synthetic blend that honda recommends and is the equivalent viscosity of 10W40.

I believe the Redline MTL will be too thick for the M5OD and will exacebate the problems the tranny already has (grinding, gear chatter). When I do my clutch soon, I plan on keeping the ATF in there and deal with the tranny problems as best I can. Unless someone has a better solution?

Randy
88 F-150 M5OD with problems.

 

I just talked to Pennsoil Tech Support. ATF is equivalent to a 5W20 multi-viscosity. Non synthetic uses polymers to attain the 20 weight and the gears tend to sheer the polymer and then you lose the 20 weight capacity. Use full synthetic ATF and you will not lose the 20 weight. Also he said I could run 5w30 or 10w30 (he thought would be better than 10w40. Don't run gear oil as there are additives that are bad for the syncros (at least in the Mazda 5 speed). The ATF will improve fuel mileage due to lower friction.

 

[font size="1" color="#FF0000"]LAST EDITED ON 07-Sep-00 AT 07:39 PM (EST)[/font][p]Have any of you checked your clutch cylinder? Mine is leaking fluid slowly (two week time period).

I notice mine starts to get hard to shift & grinds almost constantly when the fluid starts to get low. I had to refill mine today before work because it wouldn't come out of gear or go into the next gear. (That dual exhaust sounds pretty good at 55 mph in third grear)

Anyway it's just a thought.

 

Measure the slave cylinder movement. Internal slave cylinders can be measured through the port on the tranny. This will tell you if your (internal) slave cylinder fully releasing the clutch.

Also, my '95 had a worn nylon bushing where the clutch petal meets the clutch master cylinder. The master cylinder arm was pushing at an angle, limiting the throw. Replacing it sure improved my shifting, but I need to bleed the master cylinder to get it up to specs.

Adding synthetic ATF fluid didn't improve my shifting at all.

 

It's shifting perfectly on all shifts, especially on the 1-2 shift with the Mobil 1 synthetic ATF I put in last night. I have driven 50 miles including a cold start this am (ambient temp 70 degrees) and no chunk and no grind. The 20w50 motor oil is just too thick (I guess), but the 10w40 probably would work as I first went to that before trying the 20w50 (as explained in my earlier post) and I recall now that after putting the 20w50 in the shifting got much worse.

My slave and master cylinders were all new in February 2000 and my mechanic who did the clutch checked that also. All is well, except possibly that the tranny is a tad noisy and some of the take of gear rumble is back with the thinner oil--but she sure shifts nice now.

As for the viscosity of ATF, I was told by one oil company 5w20, but another company I emailed and got back a reply that ATF is 20 weight, so I called them and got someone else who said it is 10 weight. I find this all the time in automotive tech--nobody seems to really know what is going on and everybody says something different (look at the threads on cat-back exhaust systems for example).

 

I would say Ford new what they were doing when they put ATF in the tranny. Those engineers sure know a whole lot more about what they built than I do. I ran ATF in my first M5OD for 171,000 miles and it shifted perfectly every time hot or cold, till I twisted the input shaft. I felt it performed quite well for a light-duty Mazda. It's only a matter of time before the torque of the Ford engines tear them up. I try not to re-engineer what they get paid to engineer. If they say ATF, use ATF. Makes perfect sense that a lighter weight oil will work better with tighter tolerance bearings. Thick oil won't go in the small spaces, and bearings and such don't like not having oil.

 

I've run into the same confusion as everyone else on which fluid to run in the Mazda 5-spd...and I'm a BSME!
A couple of years ago I switched from ATF (with 50,000-mile lube change) to "Redline" brand MTF for added lubricity under extreme load conditions and, hopefully, better shifting and NVH characteristics.
Yep, the tranny shifts really hard 'til warmed up.
Yep, it is still the mediocre POS it's been since Day One.
Nope, that tranny won't get any more attention from me...I'm sidestepping the rebuild issue; it's being replaced with a previous-generation bullet-proof NP-435 and an Advanced Adapters "Ranger III" Overdrive unit, which itself uses the bullet-proof internals from a similar-generation Warner Gear T-98 tranny.
Right now I am going through the 435, and am planning on using Redline MTL (gear oil) again.
Eddie

 

67ccougar: You are right. Anytime you go outside the manufacturer's bounds you can get in trouble. Anyway, I was sort of led that way by several sources of advice. Now I know and everybody else can skip the bad experience.

Since the Mazda 5 spd apparently is a light duty tranny, I would like (if mine ever goes) to switchy to a ZF wide ratio. The dealer quotes $2000 for a reman ZF, but 2400 for a reman Mazda. So if it will fit without too much trouble, it will be a ZF.

 

My '91 Ford/Helms Spec Book reads thus:
Ratios (to 1)

M50D:
1. 3.90
2. 2.25
3. 1.50
4. 1.00
5. 0.80

ZF (Close Ratio)
Gasoline
1. 4.14
2. 2.37
3. 1.42
4. 1.00
5. 0.77

ZF (Wide Ratio)
Diesel
1. 5.72
2. 2.94
3. 1.61
4. 1.00
5. 0.76

Watch integral bellhousing bolt pattterns carefully...460 and Diesel units won't line up; 300-six and 351 V-8 (er, 4.9 and 5.8L) close ratio only.
Additionally, work out the gear spread percentages on the M5 ratios; there is an interesting progression there.
Already thought out the ZF for mine--just try and find a 4wd ZF...
Eddie

 

So the ZF wide ratio only fits the diesel. Well, the narrow ratio would suffice, though Jasper Transmissions supposedly can custom build the tranny. I heard the late 90s Ford truck can be purchased with a 6-speed manual. Anyway, my tranny is working for now and my latest problem is the clip that holds the clutch master cylinder plunger to the clutch pedal shaft lever is shot. I have a clamp on the end of the pin but need to get a handful of those cheap (but likely expensive) plastic clips. Why didn't Ford use a washer and cotter pin? Too expensive? If that plastic clip fails and the plunger comes off the peg on a shift there would be one nasty crunch from the gearbox. Sounds like this bit of cost saving should go into a recall.