M50D popping out of fifth

[IAmTodd]

I've recently swapped an M50D from a '91 Explorer into my '94. Trans is great with the exception that it will pop out of fifth gear. it will go through gears 1-4 with no problems or sounds(2nd seems to have excess vibration through the shifter?), reverse is great, fifth will slide right in but as soon as power is applied the shifter begins to works its way out. You can visibly see it moving towards neutral. The feel going into fifth is also different. The other 5 clears have a noticeable click when they go into gear which seems to hold it. Fifth just seems to slide in without a click.

When I pulled it from the truck you could see RTV around the top cover, the shift rail plugs, and the tail housing. I looked at this as a good sign it had been freshened up but I was wrong. All components are new concerning the clutch and shifter bushings. Is is possible that I have one too many washers sandwiched in with the shifter bushings? I tried to match what came out. Also, the lower bushing was MIA when I changed it. Hindsight I should have pulled the top cover to find it.

I've read that it can be anything from the shift fork, the adjuster on the side (I attempted to adjust with no results and returned it to the position I found it in) or the reverse gear being in neutral. I'm just trying to size up the job so I know what to look for once I pull the trans again.

 

[PlumCrazy]

Sounds like the detent spring and/or ball on the shift rail is broken/missing. I would pull the top cover off and pullout the 5th/reverse rail and investigate.

Sent from my C771 using Tapatalk 2

 

[Explorin94]

Will it stay in 5th if you hold it there?

 

[IAmTodd]

Sounds like the detent spring and/or ball on the shift rail is broken/missing. I would pull the top cover off and pullout the 5th/reverse rail and investigate.

Sent from my C771 using Tapatalk 2

If that's the case, any idea where I can pick up the necessary parts?

Will it stay in 5th if you hold it there?

Yes, no problem holding it in place. No odd sounds, it just tries to push against your hand.

 

[PlumCrazy]

I should have whatever you need.

Sent from my C771 using Tapatalk 2

 

[IAmTodd]

That'd be great. I'll let you know.

Is this something that could be done with the trans still in the truck or am I better off taking the time to pull it out?

 

[Explorin94]

On the end of the shaft where 5th and reverse is there is a ball bearing that is inset into the mainshaft which keeps the gear from turning freely on the shaft. It will stay in reverse without problem and can be held in 5th while going down the road. It sounds like that bearing is gone or the gear may be bad. I say either take that transmission back if there was a warranty on it or take it apart and see what you have wrong with it. This can be done by just taking the back half of the transmission apart while it is still in the truck.

 

[IAmTodd]

Will it be obvious if that bearing is bad?

Is is one of the bearings in this picture?

 

[Explorin94]

It is a single ball that goes in a detent on the shaft. It is often overlooked and lost while disassembling the transmission. Look at the inside of 5th and reverse you'll see what I am talking about. Look at the machined part right before the bearing....it will be there.

 

[IAmTodd]

Oh, I thought you meant a full bearing and not the spring and ball that Plum was referring to. I'll pull the tailshaft this weekend and see what I find.

Thanks for your help guys.

 

[IAmTodd]

Good progress was made today. Only took me an hour and a half hour to get the tailshaft off the trans. I drained the fluid first and there was a bit of material stuck to the drain plug. Much less than last time though.

This is where I'm at:

My one concern is in the upper left area where the fluid is pooling there is debris. This was behind the plastic cap sitting above it.

Not sure where it came from but it is not metal as it isn't attracted to a magnet.

Tomorrow after work I'll begin to work the bearings and gears off and see what I come up with!

 

[PlumCrazy]

That is probably what is left of your missing lower shift bushing.

Sent from my C771 using Tapatalk 2

 

[IAmTodd]

OK gents, I have good news and bad news. Good news is everything is out of the truck. The main shaft bearing was a bitch but I prevailed.

Bad news is everything looks good. Ball and spring are present, there's 3 definite clicks to it. Fifth gear also looks good and is in one piece. Syncros all look good as far as I can tell. They do not have pads on them from what others have described but have brass ribs. I can take a picture if necessary.

At this point it's a shifter issue. Was I just not adjusting it properly on the side? I can provide any pictures that you would think to be relevant.

 

[IAmTodd]

I may be onto something. I was playing with the slider and the notched wheel(? I'm sorry if I'm not using the correct terms) that fits inside it. I noticed that toothed wheel has an offset. Is it possible mine was installed backwards? Mind you this trans has been open once before.

This side was against fifth:

This was against reverse:

What leads me to think this is there are two areas worn where picture 1 sits against reverse. Not sure if that's normal or not. Just grabbing at straws here.

Any help is greatly appreciated.

 

[adsm08]

Not sure where it came from but it is not metal as it isn't attracted to a magnet.

There are several types of metal that are not attracted to a magnet, and large, important parts of your transmission, like the aluminum case and brass shift synchros are made of some of those metals.