H42 in a FJ40

[Waterboy]

I just purchased my first fj40. Its a 1970 with a F and 3 on the tree. My questions is how difficult would it be to install a H42 transmission from a FJ60 into my Fj40? I have an opportunity to get a H42 tranny for cheap. Also have the opportunity to get a 81 Fj40 4spd tranny and transfer case, but needs to be rebuilt. What would be the best direction to take?

 

[Living in the Past]

The H42 out of the FJ60 won't work unless you get the transfer too. Plus the later H42 will be longer than the earlier ones. Making the rear drive shaft pretty short. The 81 FJ40 should have a split transfer already and the shifter will be in the right location. The FJ60 the shifter will be further back. The crossmember will have to be removed with the spit transfer case and the right crossmember installed. Plus you will no longer need the rear motor mounts since the transfer case will now be used instead. A small body lift might also help with clearance at the back of the transfer case. When I install the earlier H42 (pre 8/80) I used a 74-78 traansmission cover and just cut the back off. I also had to modify the passenger's side a little to fit.

 

[LAMBCRUSHER]

I'd go w/ an H41 and three speed case. Higher cost, lower gears- all factory parts.

 

[Waterboy]

Thanks for the advice. I have to decided to get the 4spd and transfer case from my friend with the 81 FJ40. The h42 seems to much more involved and advanced for a beginner such as my self.

Thanks,
Preston

 

[pappy]

If the H42 is anything similiar to the H55F, which I think it is, I needed to do the following to my 1969:

• Remove the crossmember and install one further back.
• Install a 1" body lift.
• I used the dog-ear engine mounts on the bellhousing, and also installed a crossmember to the tranny, just cuz.
• Modify the doghouse for the transfer and tranny shifter.
• Move rear axle back. My shaft is still only 18" long and very steep with the SOA.

As said, if you use an H42 from a late FJ60, it will be longer. You will need to use the transfer from the FJ60, along with a 4-speed bellhousing from either a FJ40 (with dog-ear mounts) or FJ60 (without dog-ear mounts).

Thanks for the advice. I have to decided to get the 4spd and transfer case from my friend with the 81 FJ40. The h42 seems to much more involved and advanced for a beginner such as my self.

Thanks,
Preston

I believe the 1981 will have the H42 and split case.

 

[grant5127]

Split transfer came into play in 8/'80 -

 

[rusty_tlc]

I am very confused.
IIRC the Toyota transmission manual shows the H41 and H42 as identical except for gearing. (The H41 1st gear has a 4.925 :1 ratio opposed to the domestic 3.55:1 ratio.) Both had a different OP shaft (splining/length?) when the t-case changed from the single cast housing to the split housing.

The H55 is almost identical except for an extended housing which accommodates the gears for the overdrive.

 

[pappy]

I am very confused.

The H55 is almost identical except for an extended housing which accommodates the gears for the overdrive.

Correct, and that extention was present on the H42 in later FJ60s.

 

[rusty_tlc]

Correct, and that extention was present on the H42 in later FJ60s.

The change was probably about the time they stopped importing the FJ40.
It makes sense, Toyota could offer the truck with a 4 or 5 speed without changing anything except the tranny.

 

[psreno]

Hi Waterboy! Welcome to the madness.

May I ask what you like about the H42? It has about the same upper and lower gearing of your current three speed. You can drop a floor shift into that tranny rather easily.

Usually, if you are going to swap the tranny it is for a better gearing on at least one end ideally both.

I think the 3 spd is plenty strong for the F even with 33's - or if you're really glutton for punishment 35" tires. And they can be replaced for about the price of shipping - which btw isn't much since they are light.

Now if you can find the H41 tranny that was common in Canada and Australia, then you'd have a real nice low gear.

Enjoy the forum, it's a great source of info.

 

[grant5127]

I am very confused.

Agreed, along with pappy & psreno.........

The extended housing came into play in 4/'85-........

psreno, you need to buff-up on ratios on these trans......

 

[psreno]

Why? 2.75 vs 3.55 1st? upper is identical. I did say "about". That advantage pretty much goes away if you change tcases anyway b'cuz the 3spd tcase has lower gearing than 4 spd tc.

Not enough gain for the work/cost involved in my book to swap in H42 from J3.

 

[FJ40Jim]

Definitely use the 81-later H42 from FJ40. It has the 4speed goodness (obviously) and the unbreakable split case, and the low-range is ~2.3, just like the much weaker J30 t-case.

Only downside is the lack of a P-brake.

You will also need a 74-80 4-spd BH and a pair of 4spd FJ40 D-shafts.

 

[Waterboy]

Hi Waterboy! Welcome to the madness.

May I ask what you like about the H42? It has about the same upper and lower gearing of your current three speed. You can drop a floor shift into that tranny rather easily.

Usually, if you are going to swap the tranny it is for a better gearing on at least one end ideally both.

I think the 3 spd is plenty strong for the F even with 33's - or if you're really glutton for punishment 35" tires. And they can be replaced for about the price of shipping - which btw isn't much since they are light.

Now if you can find the H41 tranny that was common in Canada and Australia, then you'd have a real nice low gear.

Enjoy the forum, it's a great source of info.

The reason for considering the H42 was a guy locally was selling a H42 out of his FJ60 for really cheap. Not a big fan of three on the tree, but might have to use it for a month or two for now.

 

[Fast Eddy]

Definitely use the 81-later H42 from FJ40.

Only downside is the lack of a P-brake.

The reason for considering the H42 was a guy locally was selling a H42 out of his FJ60 for really cheap.

Check for the e-brake. It's probably not there. Certainly something to think about.

 

[pappy]

Check for the e-brake. It's probably not there. Certainly something to think about.

The e-brake can be added to a split case.

 

[Vicm]

I had the h41 in my 40 and didn't like it much on the road, I swaped in the H42. Mine was mainly a daily driver. Toyota put 3.7 axle ratio behind the H41 in mine. I sure would have hated it with 4.11.

 

[boltonski]

Vicm - what didn't you like about the H41 on the road?

I know the OP was referring to replacing a column shift 3 speed, but I was under the impression that the H42 was a more "user friendly" transmission; gear noise and shifting, in particular, compared to the H41. Maybe not enough to justify swapping a good H41 out, but if you're comparing rebuilding an H41 to having the H42 on hand...

Dan