3 speed to 4 or 5 speed?

[mboyd]

Folks,
This is my first post so bear with me. I have a 72 FJ40 that is bone stock. The three speed tranny does not lend itself to long range comfortable travel. I'd like to replace my tranny with a 4 or 5 speed. Is there a recommended tranny to go to and are there rear end gears that are recommended? Sorry in advance if this topic has been covered in the past.

-MB

 

[crushers]

first off the 3 speed and the 4 speed both have a final gear of 1-1 so switching a 3 for a 4 is a waste of money and time.
switching a 3 speed for the H55F makes all the sense in the world. better first gear, and O/D. all you will need is a H55F from a gasser OR a H (not HZ or HDT) engine equiped cruiser. the gasser is easier since you can also scroung the bell housing which you will need. the bellhousing from the 4 speed will work for the H55F and is easier to source for the FJ40. you will need shifters, tranny mount, driveshafts (modified) tranny from the donor truck.
so:
ANY 4 speed bell housing (completel with bolts)
H55F from a HJ50 or a FJ40 (not sure if the FJ40 ever did get the H55F, i kow the BJ did but it won't fit your application)
all the related parts from a H55F donor.

the 4 speed will give you a nicer shift range around town but in the long distance travel it makes no difference.. those old 3 speeds stood up VERY well to a LOT of abuse. simple and reliable.

 

[crushers]

oh, and hte rear gearing, you have 4.11 in there now (this was not a question) so find a set out of a 77-84 GASSER 40 (3.70 gears) and bolt the complete center unit in, use the stub ends of the donor units with your driveshafts. this makes more sense than the H55F in the short term.

it really is that simple. if you are located near calgary then i know of a few sets of 3,7s for sale.

 

[mboyd]

thanks for the fast replies. I don't know some of the jargon. What's a gasser?

 

[LDowney]

thanks for the fast replies. I don't know some of the jargon. What's a gasser?

Gasser = gas powered

Also, this section is focused on 70 series Cruisers rather than trucks from the 1970's. However, a number of people in this section are well versed on the 40 series too and eager to help. If you want to run your questions through the 40 series section, you may opt to go here too, https://forum.ih8mud.com/40-55-series-tech/

Finally, the Tech Links has reference data that you may want to review, such as this on transmissions & transfercases http://www.cruiserfaq.com/08-00.php

Welcome and good luck