Taking out the 3 speed and putting in a 4

[gofast]

Hi Guys,

Looking at a donor 55 rig for my truck cab project. It has the three in the tree but comes with a four speed for a swap.

Not being too familiar with these pigs, I'm wondering if there's any odd fitting issues that I have to consider like cross members, out put splines etc. Motor is a 2F.

I'd be greatful for any advice

Cheers,

John

 

[bigsal]

Are you keeping the three spd TC? If so you will need to deal with the linkage. I am in the process of collecting the parts for that same swap, except mine is a floor shift. I have been told I'll need the shift fork and shaft from a four speed TC and install it in the three speed TC. You will also need the input gear and spacer from the four speed TC to be installed in the three speed TC. There is a different spline count. Best of luck.

 

[gofast]

Thanks for asking.

I didn't even think about the transfer case but I'd replace this as well. No compatibility issues. The only reason I'd keep it is if the crawl ratios are better with the 3 speed. Anyone know?

It looks like I'd lose some floor space but I'm okay with it. Current linkage on the 3 in the tree is worn anyways.

For that matter whats the gear ration of the diffs?

Thanks from a noob pig guy.

 

[bigsal]

I don't know the ratio off hand, but can tell you that the 4 spd tranny with 3 spd TC is the lowest crawl ratio you can get with stock Toyota stuff from that time frame. ( ie.. keeping the ebrake on the output shaft). You diffs are probably 4.11's (?) Mine is a 72 and that is what I had stock ( i've been told, haven't counted it yet).

Lot's of folks do that swap and keep the three speed TC for the crawl ratio. Pretty common for the 40, 45 and 55 folks. The qeustion becomes what 4 speed tranny do you have. Some of the ones sold outside of the states get really low first gears. I have a US model that is not the ultra low, but I will be fine with that anyway.

I've done exhausted my knowledge at this point since I am doing the swap when the snow melts here.

 

[uglyoinker]

I'm not exact but in ballpark. 3 speed tcase is 2.28 to 1. 4 speed tcase is 2 to 1. If you have a 3 speed tcase from the last couple years it was used as in 72ish to 74 it has the needed strengthening ribs around the idler shaft. Otherwise 3sp cases not very strong, depending on your application of course. If you're wanting to conserve or to get crawl ratio a popular combo is the chevy sm420 to the stronger 3 speed tcase. Sm420 granny gear is 7.02 to 1 compared toyota tranny 3.55 to 1. Huge difference!
Just my couple cents. Don't flame me.

 

[cruiser_guy]

I'm running a non-USA H41 4 speed Toyota tranny with the three speed transfer case. The H41 has a 5:1 approx. first gear ratio.

 

[rw74228]

I actually just got a 2f 4 speed with t-case too that I am looking to put in my 72 fj 55. The engine is a 1987 and was also going to post on here to see if there were any issues with everything fitting etc. when making the switch any help would be much appreciated.
thanks