Hey guys, new to the forum and I got mucho problems. Long time coming has been a clutch job on my 88 f150. Started having problems getting into 2nd gear about a month ago and two weeks ago it finally left me on the side of the road. Tried to drop down from third to second and it wouldn't go in any gear. Finally I got it into third but I couldn't get it out of gear so I pulled over. Got the truck into reverse after that but it would only back up four or five feet then the wheels/transmission would lock up. I could keep backing up like that but only four or five feet at a time.
Now this week I finished up a clutch job on it. First I replaced the clutch disc, pressure place, slave/throw out bearing assembly, pilot bearing and the hydraulic clutch line. Got everything together and down the road and it does the same thing. Take off from the stop sign and it won't go into second gear. Pull over and tried to back up and the wheels/transmission lock up again. Got it into first and tried to drive home but it still wouldn't go to second and this time wouldn't go back in first. Also at the time I'm thinking the clutch is stuck engaged because it will only idle with my foot on the clutch pedal. Once I start to release the clutch it bogs down as if the brake is on with it in gear. Yes I'm sure it's in neutral lol.
I tow it home and replace the clutch master cylinder this time and when I turn the truck on its the same thing with the clutch. Truck will idle while I have the pedal pushed in but once I start to let it out the truck begins to bog down. This morning I disconnected the drive shift to see if the rear end would spin freely and there's no problems there.
It only makes sense to me for the problem to be in the tranny but I don't know where to start.

Thanks for the help guys, I need my truck back!

 

Moved to the proper location for your truck year.

 

I suspect you have broken or misaligned shift forks that are causing your transmission to shift into multiple gears at once.

The M5OD has a removal top-cover that you can access from inside the cab. I'd start by taking that off, because something is very wrong inside your transmission.

 

When I had it down I took the top plate off hut I only glanced inside. I didn't know what to look for but I thought I'd give it a look since it's down. I've taken apart and reassembled a manual Trans before but I'm no expert

 

Try searching "M5OD" and "M5R2" under my ID. You'll find a few threads w/ pics where I had the cover off a couple times to solve some issues with my forks.

 

The forks come up with the lid. Look at them. Typically they wear down to paper thin and won't move the slider on the main shaft. They should be about 1/4" thick, and likely very easy to tell that one doesn't look like the other.



You can buy the forks and change them out pretty easily. Knock a few pins out and slide the rods out and swap them. When installing cover again, make sure the shifter is in NEUTRAL and then make sure the sliders on the mainshaft are also in NEUTRAL. It will go together pretty easy.

The big issue with these transmission is to NOT REST YOUR HAND ON THE SHIFTER. That is what wears the forks out because they are very soft metal and the ATF fluid they use does not work well for wear on items like this.

 

Since you have a '88, assuming the transmission hasn't been touched, the forks are a little more involved to replace. It's not a big deal and you replace with the later ones - I mentioned the details in one of my threads.

 

Thanks for the replies, I haven't gotten a chance to open it up yet but I think I will this weekend. Still a little confused though, are you saying it's stuck in gear because the forks could be broken? What about the reverse gear problem

 

My only experience with the shifter being stuck was because I had it in gear when I removed the fork assembly/cover. But it's entirely possible that you got it stuck because of a fork failure. Reverse problems are quite likely related.

Take the cover off and see what you've got.

 

Right now it sounds like it is stuck in 3rd gear, as the fork wore enough to not grab the 3-4 slider anymore. Thus leaving it in the last gear you put it in. You can sometimes shift it into other gears sitting still with engine off. But if you try to drive it, it will just bind up and not move because you can't turn the shafts at two different speeds at the same time.

Remove the cover and see what is going on. Pretty sure it should be a simple fix.

 

Took my cover off today and unless I don't understand what I'm looking for, these forks don't look bad to me... Maybe I'm lost though

 

I feel like it probably is indeed an easy fix but I don't know what I'm doing and I'm afraid to do more damage. Pretty much being forced into taking it to a shop I think. With it in neutral though I spun the input shift and the output shift spun as well which points to it obviously being stuck in gear somewhere(3rd or 4th). Don't want to get taken for a ride at the shop but when knowledge runs out what else is there...

 

The 1st/2nd and 3rd/4th shift collars appear to be in the neutral position, so I would look at the rear of the transmission, and see if something is up with the 5th/R shift assembly. The 5th/R shift fork is down inside the case.

 

Those forks appear to be wiped out. I would replace those. You will see the difference in the new ones. Not an uncommon problem with these.

 

The forks look fine to me. They need to be about 1/4" thick to fit the sliders. If you look at the nub at the end of the fork you can see it is thick(about 1/4"), where the rest of the fork is narrower. If it was worn out that nub on the end would not be there. When I replaced mine, that nub was about 1/16" thick and near almost gone.

Yes, the shaft area looks okay. 1-2 slider and 3/4 slider appear in neutral and not damaged. FYI: 3/4 is in the front of the box (near input shaft).

The 5-R fork is in the rear housing, that lever sticking up near the case moves it. A wrench should be able to move it back/forth. It appears to be in neutral(looks like it is straight up).

Now I would start investigating the shifter itself. The gates where the shifter bolts in may be out of whack and that is giving you the problem of not being in neutral or two gears at once.

Clamp the lid in a vise and carefully shift it through the gears watching the forks.