Need serious techincal advice on my M50D transmission.

[gw33gp]

I don't know about the "dots" being lined up but that doesn't seem like it was the problem. The transmission worked perfect for 4 to 5 months after the rebuild. It then popped out of 5th a couple times but I made a concentrated effort to make sure it was all the way in 5th gear after that and that worked for a while. It seemed to get slowly worse over the next 9 to 10 months and then on my way to Kansas it finally would not stay in 5th at all.

Now that they installed the new 5th gear and slider, it is working perfectly again. I think their assessment that the broken bottom shifter bushing caused it to not be all the way in 5th gear and caused excessive wear resulting in it eventually popping out of gear.

 

[NakedDucks]

I understand what you’re saying, but all of that could be caused by the collar being installed backwards. It’s thicker on one side than the other. And being that it was staying for a while it wore out that bushing and then cause it to crack, and after a while it wore even further into it wouldn’t stay at all. That’s why it was worn. It’s no big deal, and they fixed it for free! So I would continue rolling with it.

 

[Shran]

If the 5th/reverse slider was installed backwards, it would be immediately obvious. Would have had issues staying in gear or not going into gear at all right off the bat. From what I remember, the slider itself engages with the inside of another part... if it's backwards, it won't even come close to engaging, and if the hub it rides on is also backwards, it's impossible to install the half moon clips that hold it in place.

Bottom line to me - the shifter bushings just suck... plastic doesn't last forever. The first M5OD I rebuilt had no bushings left at all and the entire 5th/reverse cluster was junk, and I am convinced that it was because whoever was driving it had to hold it in gear or jam it into gear until it blew up.

 

[gw33gp]

I replaced the top half of the bushing at around 125K miles because I found it broken when I did the shift rail leak fix. The bottom half of the bushing was still good and I was able to get just the top half from Ford, so I only replaced that one. Apparently, the person that did the rebuild at 250K miles only saw the top one and felt they were both good. A year later the bottom one was ground up into sand size pieces of plastic in the gear box.

Those plastic bushings do serve their purpose but should probably be replaced every 150K miles or so. I was not able to find just the bushings this time. I had to by a complete shifter kit and the shifter stub was not the same as mine. I use my old shifter stub and the rest of the shifter kit and threw away the new shifter stub. I should be good for at least another 150K miles.

 

[gw33gp]

An update on this problem. In June of this year, the transmission started popping out of 5th gear again. I decided to find a remanufactured transmission. That was difficult because I have the manual shift transfer case with a transmission tag 1L54-MA. Final resolution on that is to obtain a transmission with tag 1L54-HB and exchange the extension housing.

I have talked with the original rebuilder and they asked me to bring it back in to them and they are going to try to figure out why this is recurring. I will post what they say.

 

[gw33gp]

Well, about 8 months after installing the second 5th gear and slider, it would not stay in 5th gear again. I decided to buy a remanufactured transmission from Zumbrota.

I took the original transmission back to the shop that did the rebuild so they could try to figure out what is going on. They found 5th gear is worn again. They said it is the engagement teeth that are wearing. They don't know why it is wearing, but told me they can't get OEM part for that transmission anymore and the aftermarket gears may not be up to the job. I suggested trying Zumbrota for the gears and they told me if I think I can get any better gears, go ahead. I spoke with Zumbrota and they pretty much felt that all the gears probably come for the same manufacturer. They said it possibly could have been just a bad gear. I am going to ask my brother to order it because he can get a discount.

I really like the remanufactured transmission. It shift better than my original one did, even when it was new. It always had slightly strange feel when shifting into 3rd. Occasionally it would almost feel like it was brushing another gear. It also had hard shift into gear when cold. When I switched to Royal Purple Synchromax it made the hard shifting better. Which brings me to the subject of synthetic ATF. Zumbrota instructions were to use only non-synthetic ATF. I called them about it to find out why. I was told they felt synthetic ATF causes problems with synchros. I told them, I used synthetic in my transmission since the first oil change and why I did. I was told I could use whatever I want, but if there is a warranty problem and they determined I used synthetic, they would not honor the warranty. I ended up putting Castrol Dex/Merc and it is working very well so far. I will continue using it at least until the warranty expires and maybe always.