Currently I have a w4_ trans in my 1985 short bed reg cab. Not sure of the last number... 6 maybe.
I have a W55 sitting in my garage but Its missing some pieces. No shifter, no driveshaft, no mount, just the transmission.

Ive been searching the internet and asking as many toyota people as I can find and so far what Ive gathered that the W series transmissions are same cases but with a different amount of gears and different gear ratios. So in theory I have everything I need to do the 5 speed swap.

Just need a confirmation that I'm correct.

Thanks guys

 

i think so yes. im 60% im correct, all the time lol jk

yes, it can bolt in. issue would be the rear trans mount has to be replaced/moddified.

my buddy n i swapped out the 4spd (in an 87) with a 5spd (i think was a w56) all we did was fab the rear mount. came with a shifter. but try test fit ur 4spd one into the 5spd one, it mite just fit

 

yeah u can and you should have everything u need
i swapped out my old w42 4 speed for a w56 5 speed out of a 91+ yota pickup everything pretty much swaps around. the towers are different on them both though as the shifter sits further back in the 89+ so i swapped them around and used my w42 shifter tower housing on the w56. i didint even have to change my driveline or the rear trans mount as the trannies are both the same length, guess i got lucky with the rear trans mount. also your 85 is most likely a mechanical speedo cluster like mine is and my w56 was an electronic so i swapped the mechanical and electronic gear plugs or whatever they are called "the part where the speedo cable or cords plug into the tranny" and also swapped the plastic gear from the electronic speedo gear and put it on my mechanical speedo gear because they are both different.
these things. http://www.google.com/imgres?q=w56+...=140&tbnw=182&start=0&ndsp=22&ved=1t:429,i:71

 

The transmission came out of an 87 pickup long bed so speedometer mechanics should be the same. My big fears were the shifter and drive shaft. I think I might attempt to swap them this weekend.

 

If the tranny is the same length the drive shaft should fit

 

Oh and the shifter from my 5 speed fits in my 4speed, dont know what exact tranny it is though

 

Done this several times. All you should have to really do is swap the transmission housing. While you have it apart I would go ahead and get a lightened flywheel, and upgrade to a better clutch. This alone makes for a very rev happy setup.