I have a 1981 F-100 I6 300 (4.9L) with 3 spd manual that was on the tree but is now floor shifter. First gear is ate up and it will not stay in gear (grinds or pops out instantly). I could fix it if I could find the part but haven't had luck in finding that gear. The other thing is not sure positive the type or transmission. Oh, I did replace synchronizers and on visual inspection of the gear, its ate up (didn't look to terrible but it instantly noticeable).

I thought i might just swap to a different transmission, but I don't wanna do to much extra work. Like if switching to a 4 spd, I heard something about center hump mod due to the transmission being taller. That would not bother me much, but I don't wanna have to change drive shaft. I want plug and play :-) I saw other 3 spd transmissions for sale online but I don't know if they will bolt right up or if I might have to change tail housing and bell or what.So, what you gentlemen can help me with is, What transmission do I really have? Anyone know a place that will have the gear I need? What other transmissions (3 or 4 spd) can I use with out having to change much?

Thanks for you time :-)

 

Welcome to FTE

The transmission you have I believe is a 3.03 3sp thenk non-sync first gear and why it may be chewed up?
Now as for what will fit just about any stick transmission will but how much work it will take is a different story.
Another 303 is a bolt up and less work as all your part will work with it.
If you get a replacement just make sure the out puts are the same. If you drive shaft slips into the trans the other trans needs to do the same.
So bolt to the out put yoke and the slip is in the middle of the drive shaft.

Any 4 or 5sp trans you will need to get the trans tunnel hump plate as they do sit higher and the shifter may come out in different places.

Drive shafts will have either a slip joint into the trans think like your 303 where others have a Ujoint yoke that bolts the shaft to the trans and the slip is in the middle of the drive shaft.

Pre 83 treans / bell housings used a linkage clutch, like yours, the later trans use a hydrolic clutch

So with that information should help find a trans that should work.
You have T18 & NP435: both have a granny first gear but you start off in 2nd 99% of the time.
They come with the 2 different out puts slip & bolt yoke.
The bell housings remove from them I just dont know if your bell will have the right pattern to bolt them up.
I also dont know if you can use your drive shaft without mods?
I can tall you the T18 & NP435 do swap between each other as I have done it.

There is a SROD that is a 3sp with over drive, some call it a 4sp where 4th is the OD. They say this trans is a little on the weak side.
The bell dose remove from this trans.The 1 I have dose have a slip out put shaft, dont know if they come any other way?
I dont know if you would need to do drive shaft mods or not with the trans?

Now the 5sp trans all use hydrolic clutch so would need to swap in peddles and the clutch master.
Also you would want to get the cross member & brackets as they may be different than yours.

The M5OD-R2 I think it is is a bolt in and no shaft mods as a member did this swap on his 84.
Thing is it uses a hydrolic clutch so you would need a peddle swap.
Also the newer ones do not have a hook up for the speedo cable.

Then there is the ZF5 this is a HD trans and is hard to find in good shape and is $$ to rebuild.
Same as above with the M5OD-R2 for work to install..

With any of the above trans swaps if you can find a complete truck to get all the parts from is the way to go.
Maybe it is easier to find a used truck with a good trans to get that from and later as you have time get a trans to get that truck moving again and sell it or part it out as you may make your money back on it?

When I rebuilt my truck I bought a parts truck and used a lot of it in my rebuild. Some parts I knew I would not use I gave away, long bed frame, tail lights & rear bumper rest I used.
Good luck
Dave ----
https://www.google.com/search?q=ford...client=gws-wiz

 

Ok, Thanks. I will look for a 3.03 with slip in shaft. :-) I will also check to see what bolt pattern my bell housing is and see what all it will fit.

 

Ya, I swapped out a 3.03 three-on-the-tree transmission for a 1991 M5R2 5spd.

The 5spd if I recall correctly is about 3/8" longer than the 3 speed, so I used my existing driveshaft and slip yoke without issue.
I also re-used my existing speedometer cable, it just plugged right into the 5spd.

Since my truck was an '84 though, it already had factory hydraulic clutch, so that made it a fairly easy swap for me.

 

The 5 speed would be worth any headache you had putting it in place. Other than swapping in a 5 speed, I think I would just look for another 3 speed like you said you were going to do. I have never looked for one, but suspect you might find a better selection in the older 70's trucks. I have never messed with them, but have a feeling they would bolt right up.

 

I will stay with the 3 spd. I would go 5, but I have the manual clutch and want to do it as easy as possible. I saw a few 3 spds on E-bay and I think another place used for $500 and under. I heard about 2 different size input shafts. Time to take mine back out and get some measurements. :-)

 

That's the way to do it.