Trans rebuilder says M5R1's only last 3-5 years... | Page 2 | Ford Explorer Forums - Serious Explorations

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Trans rebuilder says M5R1's only last 3-5 years...

Just an update, it's been about 9 months. The shift action from 1-2 and 2-3 remains more notchy than I would have hoped, and the 2-3 shift occasionally will grind now. I tried Synchromesh in place of the Mercon fluid and it didn't make much difference.

I'm debating whether to 1) confront the shop that did the rebuild (although the warranty was only six months and thus expired), 2) Buy a shop press and rebuilt it myself, or 3) go with a different rebuilder like Zumbrota @ Rockauto.

I'm leaning towards rebuilding it myself since I've done it before. But I have to say, I am not looking forward to this.

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Buy a spare trans and rebuild that so you can swap it in as soon as the old one comes down. That way you can take the time on the rebuild .


Just sayin before you jump into things - seriously ;)

First Off & BTW - for our information; how many miles on the rebuild since installation?

1-2 & 2-3 Notchiness: Invest $18 and drain/refill with Valvoline Full Synthetic ATF as I previously recommended in this thread.
REASON: I'm sure that you have a lot of steel bearing break in material and brass synchro material floating around in there.
NOTE: the replacement rebuild Bearings & Synchros are made in CHINA as opposed to the Mazda OEM finely machined Japanese sourced parts.

2-3 Shift Grind: This could quite possibly be the need to bleed the Slave Cylinder.
I've had this happen to me a few times and it alerts me it's time to bleed the hydraulic system.
I generally do it at 30,000 miles, at the same time I change the Transmission and Transfer Case ATF Fluid.
Invest in a Harbor Freight Hand Vacuum Pump ($20) and bled the slave cylinder that is located "conveniently" within the transmission.
To accomplish this, there is a bleed nipple on the drivers side of the bellhousing - 3/8" if I remember correctly.
Use the box end of the 3/8" wrench, AND you might have to grind the "box" end down thin so as to be able to have the CLEAR Vinyl bleed hose down as far as possible on the bleed nipple so as to attain suction with no air leak.
Use a quality brake fluid such as Valvoline Dot 3/4 - $7 to $8 a Quart at Pep Boys.

My Bleed Procedure:
Make sure to suck out most of the the OLD fluid from the Master Cylinder.
Fill up with new Valvoline Dot 3/4 Brake Fluid - leave Master Cylinder Cap on BUT loose.
Go underneath, open up bleed nipple, suck away with HF Vacuum Pump.
DO NOT let Master Cylinder go dry, refill, and repeat a few times to ensure you get all the old brake fluid out of the system.
Every once in awhile during the bleed procedure, get in the cab, and CAREFULLY pump the clutch pedal a few times.
Dump old brake fluid in a clear plastic milk jug and be amazed at the color change as well as all the crap floating around in it...

Last but not least.
The two different guys, professional mechanics with VEHICLE LIFTS and HYDRAULIC TRANSMISSION JACKS THAT REACH UP 7 FEET, that I contracted to replace my clutch twice for $500 flat rate labor (using my sourced materials - all LUK brand - flywheel, clutch disc, throwout bearing, pilot bearing, slave cylinder) BOTH commented when I picked up my Ex how Absolutely Frickin' Heavy the Trans Assembly was, AND what a BEAR it was to pull the Trans Assembly off of the Engine AS WELL AS reinstall the Trans Assembly to the engine.
Convinced that in 14 years of ownership, 214,000 Miles and counting, each time that was the Best $500 "outsourcing money" I spent - You've been warned :chug:

Hope all that helps and guides you to your final decision.



Thanks for the tips, and for the reminder to "do the easy stuff first" and not jump into things too quickly. I re-bled the slave cylinder but unfortunately I am still getting some crunchiness, especially 2-3.

Just for funsies I did get a quote from a local shop to R&R the tranny. The labor charge was $1200 (this did not include any parts, or the transmission)! Safe to say I'd spend a couple days doing it myself over spending $1200, and luckily I have a second vehicle I can drive.

I've put about 3500 miles on the transmission since the rebuild, and changed the fluid twice to get rid of debris (Mercon V at first, then regular Mercon, now GM Synchromesh).

After spending too much energy thinking about what to do next, I went ahead and threw the truck on jacks and started taking it apart. Transmission is coming back out.

Going to get a 12-ton press at HF and rebuild it myself. I'm tired of getting shoddy work by others (And this way, if it doesn't work, I only have myself to blame!)

Did you install a motorcraft clutch slave? This helped my hard shifts quite a bit.

My tranny builder who i've had do at least 15 transmission for me said the m5odr1 is a great tranny. He just recommend using a quart or 2 of SAE 30wt oil mixed in with ATF. After i did this it made mine a bit quieter when in 5th gear. I mix in 2 qrts of 30wt for the hot summer months and only one in the winter. So far i have about 20k on it no issues. Of that i have about 7k of Hard off road miles.

You're tranny builder is full of **** and did not do a quality job therefore has no faith in His work.

The only reason i had my R1 opened up was precautionary, i seized my motor in the Afton canyon water crossing in the Mojave desert. I attempted to un-seize it doing 30mph 4low clutch dumps with the spark plugs removed while being tugged by another truck. My expo came to a skidding stop mutliple times trying to unseize my motor using the tranny as the tool to unsieze, and no major damage was done to the tranny during all that abuse.

This is what it looked like after i had it freshened up.

Anyways i have seen them blow in the desert, and its usualy when people are skipping across whoops in 3rd gear and it grenades. From what I've found its because the tranny was low on fluid because they didnt address the top three rubber seals with the freeze plug update. So i dont fault the R1 for that.


Got my transmission torn down today, after fighting briefly with the giant 52mm mainshaft nut. A pipe wrench and hammer finally took it down. The state of my transmission:


First off, best I can tell, my suspicion was correct and the bearings & synchros all look original. I think the "rebuilder" just installed a seal kit. Here is one of the synchros - the dark coloring is not grease:


The synchros themselves aren't obviously bad (they still grip the gear when pressed together) but there is also significant wear on the 1-2 slider and 3-4 slider teeth - a lot of the teeth are rounded off. It's hard to show in a picture, but let's try anyway:



The bearings all feel OK but I think i'm going to replace the bearings, replace the synchros, and get new 1-2, 3-4, and 5-R sliders (the 5-R slider has a lot of wear on the teeth, although it was shifting fine into 5th). Unfortunately the 1-2 slider doesn't seem to be available new anymore, so it's going to be annoying to find. There's one on eBay I might have to go after.

Just an update. Transmission is all back together, will hopefully have it back up and in the truck this evening. Rebuilding it wasn't quite as easy as I remember! I admit I am a bit nervous to see how it does!

Ended up installing a rebuild kit (bearings/seals/synchros), new Ford 1-2 hub and slider assembly, new aftermarket 3-4 hub and slider assembly, and a new aftermarket 5-R slider. Finished it up with new mainshaft and countershaft nuts.

The harbor freight 12-ton press was able to do the job. It is a little bit too small to press out one of the countershaft races so I had to improvise with some 2x4's to make the worktable bigger.