This is my tutorial on rebuilding the M5R2 transmission found in the Ford Thunderbird Supercoupe and Mercury Cougar XR7. Now we're starting with a disassembled transmission, if you need help taking it apart just start at the end and go backwards ;-). Thanks to Mike (Charkly) for helping me get it apart without reverting to my sledgehammer.
You can get M5R2 parts from Southern Gear, they know the transmission pretty well.
You can use this diagram for reference, it's for an M5R1. I got it from All Transmission Parts
It's not quite perfect, the way they show the bottom shaft going through the steel bearing plate is wrong, but other than that it will help with component positions.
You need to inspect everything carefully. There are a couple things to look for that normally wear out. First the brass blocker rings that synchronize the gears when you shift. These rings are the only brass colored rings you will find in the transmission. There are 6 of them, 4 large ones and 2 small ones. They have a fiber lining inside that grabs the gear and spins it to the same speed as the slider ring. The slider ring then can go over the teeth on the gear, and that's how the gear is shifted.
The 5 forward gear blockers have the fiber lining, and the reverse blocker doesn't - it's all brass. Most likely you won't need to replace the reverse blocker. Since you have the transmission all apart which is a lot of work, I would reccomend you replace all of the forward gear blocker rings (unless they have very few miles on them, but that's not too likely since these are what wear out). There are all brass blocker rings that you can buy that don't have the fiber lining inside, these are cheaper but the fiber ones are much better so spend the extra money for those.
Blocker rings-------------You
can see the fiber lining here
See how there is almost no
gap between the blocker and the gear - blocker is worn out.
Another wear item is the teeth on the slider rings. They should be pointy not dull. If they are dull, this will make it harder to get into gear even if you have new blocker rings. If these teeth are worn out you will need to purchase a new slider ring. I had to get the smaller one, it was $75.
Worn teeth --------------- good teeth
Bearing plate. Check the steel bearing plate for wear, if your input shaft was loose then most likely this plate has worn down. This plate is very cheap (about $17) but they did not have it so I am just going to rely on shimming the input shaft bearings. This bearing plate is unique to the Thunderbird and one for an F150 or Ranger will not work (at least that's what I was told).
Steel bearing plate
You will also need to inspect the bearings and bearing surfaces, they should be shiny with no galling. Inspect the gears to make sure they look ok. Usually under normal wear, the bearings and gears should be ok (mine were, and they had 166,000 miles on them.)
Input shaft seal $5
Other input seal (next to the main input seal) $7
Output shaft seal $5
5 fiber lined blocker rings $130
Small slider ring $75
Shims $20
Plastic spiral oiler (goes on the input shaft next to the bearing - yeah I broke
it) $5
2 locking nuts $8 / $10 **Note the larger one I got from Southern Gear
was too big and they said they don't carry one for our cars. Check with Ford
you may be able to get it through them.
Ok now we start to put everything back together. Hopefully you have a new set of blockers and whatever other parts you may need. Don't forget to get new locking nuts for the main shafts, as they are not reusable.
All empty, ready for rebuilding.
Make sure the case is clean, no metal particles or dirty oil inside. You can use brake parts cleaner to really clean it out well. Also clean all the gears, bearings, synchro assemblies, and shafts with brake parts cleaner.
Clean these holes
Take apart the synchro assemblies to clean them well. Make sure you don't lose the small keys when you take it apart! You don't have to take the springs out of them unless you really want to get them spotless. When you put them back together you MUST line up the cutout in the outer ring with the small key. There is a round dot next to one of the teeth that will help you line it up. It's a little tricky keeping the keys in place when you put the outer ring on, just be careful and patient.
Synchro assembly parts------------Cutout
for the key
Going together---------------------------All
done