Quit ignwhorin me.

 

I like my M5OD but I've never driven a ZF5, so I can't compare. I have 3.08:1 rear gears and I've not had any problems getting her going, but I've never towed anything with it. Mine had 160k on it when I got it two years ago, now at 168k, all I've done is change the fluid and put in a shifter bushing kit. I would agree that it should hold up to a mildly built 351/5.8. Good luck.

 

I have a 1991 f250 with the mazda and it is holding up fine.

I haul heavy, in excess of 12,000 lbs gross. I also pull a 20 ft flatbed trailer.
I try to be as nice to things as I can be, but sometimes they do get abused when the fan gets dirty, as they say.

The transmission has untold miles on it. The truck was originally a construction truck and then was on a farm where the owner couldn't fix anything and was hard on equipment. I got the truck on it's way to the scrap yard. They were going to drive it in and shred it. I offered to take it and it has turned out to be a very good truck. The bed is now shot, but it has hauled somewhere near 2,000,000 lbs of stuff for me in the last few years. It will be replaced with a flatbed. This truck has earned it's keep and then some.

The transmission is just starting to make some bearing noise. I like the gear ratios, but a lower first would be nice.

This truck came with a 3.55 semi float but I swapped it for a 4.10 full float. It wears 32 inch cooper st maxx tires (50+lbs each without the rim).

I will rebuild the transmission and put it back in.

 

With all the untold amounts of clutch drops hard launches and bang shifting I have done with my M50D with a 302 in front of it I am not scared to try a 351w in front if it and see how long it lasts. If it turns out that it don't like the extra go power I know where I can get and make a bulletproof c6 transmission to bolt up so I'm not worried.

 

my m5od has held up for 205k. No problems so far. But it's behind a 300 I6. So it's not like those create enough power to break anything anyways :P

I put redline mtl in mine. Shifts much smoother but when cold the 1-2 is pretty notchy.

 

This is how I always felt when I ran the mazda, I had a zf sitting for years that I "was gonna get to swapping". All I really did with the truck was 4wheel, violent hill climbs and trail rides with unavoidable mud holes and such. Reverse gear finally got chunked, but that was after turning 00000 on the odo for the 3rd time, 35's for the first 6 years I owned it, and 37s for a year or 2 before it let go.

Of course, Murphy was on my side.....I wasn't relying on it or expecting it to last as long as it did.

As abundant and cheap as the mazda trans is, I wouldn't mind keeping 2-3 on hand if street rippin was what I was after. Too bad 6 spd trans options are so expensive......can grenade a dozen mazda trans before you reach the price tag of a 6 spd swap.

I bet the Ole mazda would hold up for quite some time with a ~300 hp street truck with small tires. Of course, bangin gears and hard launches would certainly explore it's limits at that power.

 

Lol, okay I feel a bit better now. I don't wheel it daily or anything, but I do need it to be able to take more than just driving down the street. I don't abuse it on the road, it's off-road I'm worried about. Wouldn't want to grenade it and have to get towed home by a Chevy or Dodge...

 

Off road I would think it would be fine, Most of the stuff I do to it still is on dirt roads and thats just because of new tires and horrid wheel hop when it breaks loose on pavement. I guess the only time I'd really worry about it would be big big heavy tires and a poor gear ratio.

 

Found this link from another thread....
https://www.ford-trucks.com/forums/1...cs-inside.html

Something to look at before dropping it out of a truck.

 

Thanks for the link Eddie!

 

Good to read that this trans is decently tough. The 5-speed OD Mazda trans was a plus for me when I bought the truck. Gotta love a 5 speed in a truck. LOL

Would be nice to open mine up and replace the bushings, though. Tons of slop for a Mazda trans. Have several Miatas and replacing the shifter bushings does wonders for the feel of the transmission.

I also found a link somewhere about replacing the gasket on the shifter turret. Seems to be a common problem on these 20+ year old transmissions.;

 

my truck came off the show room floor with the m50d-r2 and bolted up to it was the 300 and it’s at almost 270k and the shifter bushings keep going out, anybody know what the hell is going on? I wanna say the forks are worn but it shifts through the gears still and when I put bushings in there tight and shifts great

 

Pull the top cover off and inspect everything. My guess is the problem will be obvious once you start looking.

 

Some people just can't shift for beans. Not saying that's your problem, but it's worth looking at. My brother drives a big truck, but he drove his f150 like the gearbox was full of rubber bands. I said earlier that I gross ~12k in my '91 f250. That has been done on a regular basis. If it was getting loaded, it got loaded all the way. I don't think the m5odr2 will fail just from heavy use. It has to be abused or assembled wrong.

Your forks could be worn, mine were when I got it. The previous drivers apparently liked to use the stick as an arm rest in 4th gear and ate up half the fork. The grey fluid was disgusting.

I recently acquired a zf5 and plan on installing it to see how I like it. The low 1st and reverse are what I'm after. I tore out 3 motor mounts in about 6 months trying to back up a small hill to unload. There would be a loud bang and the stick would slam over and hit my leg. The last time it happened, the motor didn't set back upright until I popped the hood because it had jammed itself in there. I welded up some captive mounts and used poly bushings. Haven't had a bit of trouble with 'em since.

Maybe you are missing some pieces and the bushing is getting squeezed too hard.