Is it possible to convert an original 4-spd manual transmission into a 5-spd in a Toyota truck?

The reason why I'm asking this is because when my uncle (original owner) had the trans rebuilt about two years ago, they told him that the gear ratios in the 4-spd man. are slightly different than in the 5-spd. The mechanic told him the 5-spd would have slightly shorter gear ratios than a comparable 4-spd man. trans. Is this true?

I'm thinking this was a bunch of BS to sell my uncle another 4-spd instead of the more desirable 5-spd manual trans. I believe the 4-spd is identical, gear ratios and all, to the 5-spd man. except for the overdrive 5th gear.

Is it possible to add another gear to make it a 5-spd? Rebuilt Toyota manual transmissions go for about $1500 around here. I'd hate to spend $1500 on another trans if all I need is another gear set.

 

Can't swear to it, but I would seriously doubt that adding a fifth gear to the existing standard 4spd is possible. Usually, the case design is specific to each type. Some internal parts bay be interchangable, but thats about it.

 

Don't even try. The housings are different and you simply have no room for a fifth gear. Save your money and try to locate a 5 speed for a reasonable price.

 

Yep... I call BS.

Oh, and I have a 89k 5spd from a 91 X-cab truck.. (4WD) You pay all shipping cost or pick up in CT

 

4 speed and 5 speed trans are different they are not interchangable parts wise but you can replave your 4 speed for a 5 speed no problem...

i tryed to get a 5 speed when my 4 went bad but couldnt find one ....i had my 4 speed replaced for 400 bucks

 

Possible? Maybe. Practical? Unlikely.

Yes, for most part 5 speeds will have shorter gearing than f4 speeds will. The exception is 4th gear, where they will usually have 1:1.00 ratios.

While the 5 speed may appear to be more desireable, it's known that some of the early ones had weak input shafts. In the early '80s, some of the 5 speeds were less reliable than the 4 speeds that previous trucks had. This issue was corrected in the mid 80s.

I think that your best bet is to find a mid '80s or newer 5 speed and replace the existing 4 speed.

 

i think the problems with the L series 5 speeds was the bearing being too small which led to a lot of failures. if you get the more desirable w56 out of a 84(or 85 i think) or newer truck, you'd need new driveshafts since it's around 4" longer. i'm hoping to go this route when i upgrade my drivetrain, since i don't like running at 3400rpm on the freeway at 70mph, it sounds like there's a plane above my head

 

Thanks.

I didn't realize they were that much different from one another.

If the 5-spd's have shorter gear ratios, then I definitely like the 4-sp tranny better. Whenever I'm at a light next to a comparable vehicle (SOHC 4cyl.) with a 5-spd, I can usually get to about 60mph in 2nd gear while the other guy has keep shifting into another gear to keep going. Everytime the other vehicle has to shift gears, I move ahead by a few car lengths.

I think the only thing I need now is a cam that will pull to 6K+ rpm's, and of course, a complete engine rebuild while I'm at it too.

The DT header and 2.25 catback has increased the RPM ability of the motor so much, that 4th gear feels almost like an overdrive gear compared to the way it was before the header and exhaust install. No wonder people always say headers and exhaust should be the first mods you should do.

Unfortunately, cruising at freeway speeds at 75mph+ in 4th gear stills gives me that "buzzing" sensation which makes me feel very uncomfortable on a 400K motor.