The 3 factory rubber plugs for the shift rail holes in the top cover may harden and fall out at higher miles, letting dirt in and fluid out. This is a ticking time bomb for any M5ODR1, M5ODR1HD or M5ODR2 manual transmission. It can be easily corrected by substituting metal core plugs Dorman 555-108 or equivalent. Another method that requires more disassembly is by tapping the holes and installing threaded pipe plugs. Either way, this fix should be a priority for anyone using one of these transmissions.

The original rubber Mazda shift rail plugs that may fall out:


Holes with the Mazda rubber plugs removed:


Dorman 555-108 core plugs installed:


Although it has been mentioned on this forum before, not everyone has heard about this issue. It's important so it needs a thread of its own.

 

thanks bob. it's been said before, but your the man!

 

I'm waiting for mine to fall out so the trans blows up and i can just scrap my truck...

 

Anybody know the purpose of these Plugs ?

 

i'm guessing to keep fluid in and contaminants out.

 

Three long bores are machined into the top cover, one for each of the shift rails. In service, the rubber plugs are intended to seal those bores.

 

Where can we get these ` Dorman 555-108 core plugs ` ?

Many Thank's for all your info...

 

I got mine at summit, there were 5 or 6 bucks.

 

I picked up some freeze plugs to do this "fix" last year but I am having trouble getting them in. What is the best way to do this with the tranny still on the vehicle.

And Bob, you working on a MROD-R2 for the truck? I have a feeling that prompted you to post this up LOL.

Same, they had to drop ship them to me though. $6.50 I think.

NAPA will get them for you as well.

 

As a matter of fact, I have a new R2 sitting in the garage.

Actually, I started a new thread about the Mazda plugs because there was a question about them buried in another discussion not directly related to this issue. I think it will be good to have the info out there under its own title.


Most chain auto parts stores carry Dorman parts. If you walk in with the Dorman part number and they don't have it, there's a good chance they can order it or cross reference it.

 

Yeah I remember you mentioned you were going to be using an R2 back in my "Manual Transmissions for 5.0"s thread.

Also, can you help me out LOL:
I picked up some freeze plugs to do this "fix" last year but I am having trouble getting them in. What is the best way to do this with the tranny still on the vehicle.

 

I have never installed them with the transmission in the vehicle. Have you tried pulling the transmission tunnel cover? If that won't work, maybe it's possible to gain some clearance by dropping the transmission down a little with the crossmember unbolted?

There should be way. If not, then the plugs could be replaced when the tranny is out for the annual clutch and slave replacement.

 

Yeah I wish I would have done it when I had the tranny dropped for my clutch job last year. Hindsign 20/20 I guess.

Heres a pic I took. It's a tight fit but I can get my hands and a hammer in there.
A body lift would make this much easier.

 

if you took those rubber plugs out and were parked on level ground, would any fluid come out? like lets say i wanted to replace them this weekend.

 

If any oil came out, it would not be enough to make a difference. Possibly a few drops of residual oil that might be present in the rail bores. The plugs are at the top of the transmission.

 

Let me know how this goes. I'm still trying to figure out the best way to do it with the tranny in.

 

thanks for the info Bob.

 

Did Ford/Mazada correct this problem in later model trucks?

 

I don't know if they still have the same rubber plugs today but if they do, there isn't much holding them in. I know that the rubber plugs were there as late as 2003 and I wouldn't be surprised if they still are. It's one of those problems that usually happens well out of warranty so it's off of the manufacturer's radar.

 

Mine were semi-difficult to remove. I had to put some muscle into it with some needle nose pliers.

 

Were the new plugs easy to get in?

 

I drove to VT a little while ago and could smell oil, didn’t see any dripping under the truck but funny thing was the carpet just behind the trans tunnel cover was wet with an oil substance.
Must be these ports.

Bob, as always thanks for your input, your knowledge and your willingness to share with the site. ltr...

 

The transmission breathes through the shift tower so it could have also been from there somehow. If the upper and lower boots are in good shape, I don't see how the fumes or oil would get into the interior. In any case, I think it would be a good time to check everything out.

 

While you are doing trans work it's not such a bad idea to do this as well:

M5R1 M5R2 Shifter Repair Kit
It's a bushing and boot replacement kit for M5ODR1, M5ODR1HD, and M5ODR2
I got mine on ebay for $16 shipped

I never did figure out how to get the new ones in with the tranny still in. I put the rubber plug back in and called it a day.

 

oh god, i hope no one would have to do that annually. My clutch was finally replaced at 130k / 11 years and I'm still on my stock slave (knock on wood)

thanks for the tip. Wish I wouldve known about this before i got my new clutch!