Anyone that owns one already knows all about the M5OD, or is soon to learn. I hear lots of stories about worn about mazdas. A local outfit that deals in tons of used ford parts says they sell a "good" (if there is such a thing) mazda as soon as they can get them in. They recomended using 50 wt synthetic motor oil as a better lube. I don't believe that the mazda is a horrible transmission, it just ain't a great one. Mine has 130,000 on it, I put a new top plate on it last year to cure the leaking plugs and worn shift forks. From what I can gather most of the problems seem to be from lack of lubrication, or from driver abuse. I can solve the lubrication part, but mine is in an F250! I want a stronger alternative for my truck because I am in the process of building a stout 5.8 to take the place of the 5.0 in it now. I know of alot of blown M5OD trannys on this board, but has anyone ever broke an internal part in one due to undue stress? (meaning pulling a load that is too heavy, dumping the clutch to hard -like on pavement-with large tires, that kind of stuff) Cause I plan on maybe pulling stunts like these. I know of one mazda transplanted into a 78 4x4 running 36in swampers with a pretty hot 302, and the owner puts it trough its paces on pavement and off. It has held up for a couple of years now this way. Is any one running a mazda behind an engine that has more power than stock? I know the later mazdas got a bearing improvement, going by the year, mine should have the improvement. I wonder if I rebuild mine at the same time I do the engine if it will hold up. Plan on a complete rebuild using a quality kit and using a thicker synthetic lube in it. Anyone have an idea what the torque rating on this trans is? let me know what you think.

 

Ive got an M5OD , It leaked a little when I purchased the truck in 1990 , I fixed the leaks . I have hauled & towed a lot of heavy loads with it , its got 180K miles & its still going . I use Mobil 1 Syn trans fluid in it , Its done fine & shows no signs of dying . I agree , Same as any other mechanical part , If its neglected , abused , it will die prematurely . The M5OD may require a little more TLC , but at least with proper care it will continue to do its job . I take care of stuff the best I can , If it breaks , I fix it . Same as anything else , regardless of what you use , sooner or later it will need repair .

 

I would put only ATF in the Mazda tranny. I use synthetic. Dealer told me I could run 10w40 motor oil and it worked OK, but to no advantage. I would not go straight 50 wt oil. I tried 20w50 and the thing jammed up. Was difficult to get into any gear. This tranny was made for a thin fluid. Just change it every 25,000 miles or so.

INLINE SIX POWER!
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!

 

The last car I had (before this truck) was actually a Mazda MX-6 GT.

It came with ATF in the 5-speed Mazda-designed tranny, but I drained it and put Mobil 1 Synthetic gear lube in it with no problems in cold or hot weather for the years I had it.

I have read a few direct reports of M5OD owners using synthetic gear lubes with no problems (but I don't think I've read them on this site), and (to the dismay of many FTE posters, apparently) I am probably going to chance using it once again on the next change-out.

At the moment I have Mobil 1 syn ATF in it, but I agree that with the wear these things get the internal specs can't be as tight as they were, and a synthetic gear oil will probably work like it did on my Mazda car. The synthetic gear lubes (I believe they are 75W-90) will probably flow much better than the straight weight 50 oil in most temperatures, and they'll have the right additives for such applications. Straight dino 50 weight probably won't.

 

I was going to try looking it up (some website where I saw it), but I there was a chart comparing gear lube weights with motor oil weights and for the same viscosity, gear lube had much higher numbers. So the 75-90 may work. Now, when I had my '84 F150 with a 4 speed OD on a 300 I6, we drained the gear lube at 90,000 miles and filled it with 10w40 motor oil. That thing is still shifting fine at 190,000 miles now and is much easier to shift when first started in really cold weather.

 

I've got a '92 f150 with 340,000 kms on it(canadian eh). It's got a 302 with pullies, cold air kit, tb spacer, headers, chip, no cat's flowmaster 2-1/2" dual exhaust and I've been running 35" tires since 65,000 km's.All I've ever done to it is change the oil, and probably not as often as I should, lots of burnouts on dry pavement, I was kind of worried when I bought the truck because I've heard may horror stories but I'm very happy with mine.

 

I figure I will rebuild the transmision with the best componants I can get, I already put expansion plugs in place of the rubber ones. I wonder if there are any other upgrades? I want to be able to work and play with my truck, maybe even pull it in our local truck pull once a year. I know better than to do completely stupid things like keep the throttle down even when the truck starts to hop badly, or drop the clutch at 6,000 on pavement. When you pull you run out of traction before you are in danger of breaking anything, unless it was on its last legs anyway. I only have 33's and probably won't ever put tires on much bigger than that. I can rebuild the M5 myself and have about $300 dollars in it total and done right. Notice no one really has trouble with their transfer cases like this? I have seen some people who could tear up even the toughest equipment. If I don't ask my M5 to do things tranmissions weren't meant to do, I think it will hold up. Also I will get a new clutch with a little better holding power and a new clutch slave when I do this. I can slip my clutch now with the 302 if I try hard enough. The slave ought to be replaced just cause it makes sense. I don't think I want to go through the hassle and cost of swapping in another type of transmission. Ford never put the M5 behind the 351, is it because they were afraid of the transmissions durability, or were they using the inherent slip of an automatic to absorb the load on the rest of the truck from the increase in power of the 351?

 

What kind of situations have any of you lost the M5OD? Dropping the clutch? To much weight? I don't understand this concept, If you are driving along the highway in 5th gear and floor it, how is that any different from the force of when you floor it in 5th with a heavy load? I'm mentioning 5th because its the weak one.

 

Near as I can tell the M5 just starves itself for lube. That and I'll bet alot of them never had the fluid changed, ever. I can't expect a transmission that tends to starve for oil to live long if what oil it gets is a slurry of Thin and broken down ATF and metal particles. Even if you take care of a transmission, you still get some fine shavings. When I put a new top plate on mine, I drained the fluid and flushed it out with solvent. I just took the drain plug out and doused the open top of the tranny with solvent. The fluid had enough metal suspended in it to give the fluid a sheen almost like metal flake paint. I wasn't happy to see it, but I know that it wasn't all that abnormal for a trannsmission with that many miles. My shift forks were worn, thats why I found a good top plate to swap in. The metal from the forks had to go somewhere, it can't evaporate. I would really like to hear from anyone who's M5 failed because of stress, not just wore out, staved for oil, abused and not maintained.
Anyone?

 

BIGBLUETRUCK: Just wondering: Did Ford put the 11 inch clutch in
the F250? Or the same 9 inch as in the F150 between the M5OD?

Is the vibration I get up the shifter caused by the nylon ball at the base being worn?

Chris

 

I have just recently pulled my M5OD for a problem. Last year I pulled the truck into my parking space went out that evening, backed it out, put it in first, let out on the clutch. Nothing. No noise, nothing. Put it in second. Same thing. The trans would only move in reverse, third, fourth, and overdrive. I don't pull anything heavy or work my truck hard at all--light loads. Its a 91 F150, SWB, 4.9, with 2.73 gears w/ 139,000 miles.
We took off the top plate and found two shift forks worn. These were replaced and now the trans works like new. I had a problem where I thought that a synchronizer in first was going out but the fork replacement fixed that too.

Marty

 

My trans is doing great at 90,000 miles. No whines and solid in every gear. Once in a while when going into first gear coming to a stop I can feel the gears meshing together. Probably just common wear. Sometimes things just go out without any notice so its hard to tell how much longer it could last, but I would guess it has along time before I need to worry about anything at all. I have heard there is a better trans than the M5OD that will bolt up nicely. It's called the M5R2. It is based on the M5OD but is MUCH stronger. Some shops have recomended these over the ZF because they have less noise and better shifting. I personally don't know if all of this is true, but if I needed a new trans I would look into this option before rebuilding the old M5OD. Phoenix Hard Parts sells these trans on ebay along with a few others. Just do a search for "M5R2" in the transmition section. They list it compatible for f-150 and f-250 with the I6, 5.0, and 5.8 engines.

 

I haven't has my clutch out but the only one I list at work for a 250 is an 11 inch. Also unless I am wrong the M5ODR2 is the full size truck version and the R1 is the ranger chassis version. I think I see a trend in fork wear here, just one more thing that makes me believe the M5 is under lubed. When I had a look at the guts of mine, the gears and such all looked similar in size and constuction to trannys like the T18 and NP435 both of which are known for being durable. I think the 1356 tranfers have an internal oil pump in them, which would explain them outlasting the transmissions.

 

I noticed that in bigbluetruck's signature, he says he has 16.5 rims. Is it possible to get 16.5 rims in the 5 bolt Ford pattern? I ask this because I had 4 brand new 35 x 14.50 x 16.50 Super Swamper TSL SX's offered to me for dirt cheap, but I have 15 inch rims. Let me know! Thanks!!!

 

Hey guys after talkting to a mechanic friend about my tranny, he said that the mazda trans is junk. I was like oh great, but to my suprize i looked under my rig the other day more closeley at the tranny and both the transfer case the the tranny are borg warner! also i put a cluch in the beast the other day and it takes an 11 inch disk. it leaks a little tranny oil and when its cold it makes a slight wispering sound. becides from the syncros being a little worn, it works fine, never pops out of gear, goes in fine.

any answers to a non mazda 1991 f 150 with an 11 cluch??

john reed