Maybe I'm wrong here, but they didn't come in heavy duty F250/350 trucks. They came in V6 powered F150's. They weigh no where near 3 tons... I'm not saying they were bad tranny's, just not for heavy duty use.
I don't know that anyone cares about this transmission--heck, I don't think I do anymore either--but in case it helps anyone here's what I found by poking around the web and asking some questions at http://www.ford-trucks.com...
The M5R2 transmission seems to have two main problems:
1) They leak from some badly-designed rear seals--that can be replaced with better ones--causing the transmision to become extremely distraught when the lubricant drains out
2) Most guys who use them say they just don't shift very well, and that it's a very unsatisfying transmission for those of us who enjoy rowing through the gears
So, no M5R2 for me. That leaves me with a choice between a T5 modified for a forward-mounted shifter, or a Tremec 3550 set up for the same.
[ This Message was edited by: zonkola on 3/21/03 4:40am ]
Very old post I know but......the M5R2 tranny also came in the Thunderbird Super Coupe (89-95 3.8 L Supercharged engines) and certainly had a higher torque rating than what has been quoted here....heck the Super Coupes had 315 ft/lbs of torque stock (or more in the 94-95) the the tranny had to be able to handle it. The SC version was similar to the truck versions but had the shifter mounted at the rear of the tailshaft housing using internal shifter rods to couple to the shifter forks.
I have a '95 F-150 with the 4.9L I-6 engine. I believe what these other good folks are talking about when it comes to torque ratings is that these bigger sixes and the small eights produce more torque than the tranny can handle over extended periods of time. I called a guy about rebuilding the tranny and from what he and my college instructor (I'm in an auto program at the college here) said, a common problem is that the engines will tend to warp the transmission case over time due to the fact that it's made out of alluminum and can't handle excessive torque. I don't know why they would design a tranny out of aluminum other than to reduce sprung weight and increase fuel efficiency. In any case, you'd have to find a shop with a very specific machine that heats up the case so that they can re form it and then rebuild your tranny. I'm currently looking into seeing what a new one costs. Anyone know of any good replacements that will work in my pickup? My instructor tells me it takes as few as sixty or eighty thousand miles to produce this problem in the tranny.