BJ40 gearbox into FJ40?? (1 Viewer)

[Ian Gunner]

I have an FJ40 with 4 speed box which is a bit stuffed and can get a BJ40 4 speed box and am wondering if it will fit straight on. BJ40 box is off 3B diesel engine with 21 spline input and 16 spline output.
Will it fit and would the ratios be OK???

 

[cruiser_guy]

Ratios will likely be the same (I'm assuming that both trucks are U.S. or Canadian), the problem is that the input shafts are not the right lengths.

 

[Mauger]

Do you know if a 3sp trans case will fit onto a diesel 4sp?

 

[RredFJ40]

I believe the input shaft length is different to make up for the shorter 4 cylinder. You'd have to get the shaft out of your tranny or an HJ tranny.

 

[cruiser_guy]

Do you know if a 3sp trans case will fit onto a diesel 4sp?

YES!! If it had the single piece case originally. ie. it's a 16 spline output shaft. The FJ55 and the FJ45LV both have the 3 speed transfer case on a "B" series 4 speed.

 

[pbgbottle]

what cruiser_guy said, diesel input shaft is too long, just have to swap the two inputs . where are you ? i have a couple 4spds

 

[Teebag]

Want to put a 2F into a BJ with the 3B and H41 what do I need to make the 2F mate up?

 

[Josie'sLandCruiser]

Hi All:

The F and H series engines use a "coarse" (ten) spline input shaft. The B series engines use a "fine" (21 or 27?) spline input shaft.

To install a 2F into your BJ42/60/75 will also require a four speed transmission from a FJ or HJ. Whether your existing transfer case will work with a different transmission I'm not sure of; the bolt patterns should be the same, it is the output shaft spline count that is the issue.

Maybe it would be easier to just put a turbocharger on the 3B for more HP?

Good luck with the project!

Regards,

Alan


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Want to put a 2F into a BJ with the 3B and H41 what do I need to make the 2F mate up?

 

[KY854RUN]

The H42 (the US 4 spd) and the H41 (non US 4spd) are interchangeable. You just need to use the 21 spline clutch disc. I'm not sure about the bell housing, but I think that they use the same one. The H41 4 spd was installed behind the 2F in the non US markets.

The main difference between the two is, the H41 has a lower first gear.

 

[cruiser_guy]

The H42 (the US 4 spd) and the H41 (non US 4spd) are interchangeable. You just need to use the 21 spline clutch disc. I'm not sure about the bell housing, but I think that they use the same one. The H41 4 spd was installed behind the 2F in the non US markets.

The main difference between the two is, the H41 has a lower first gear.

Yes, but the question is "Can a "B" series H41 or H42 fit behind a 2F?" and the answer is yes ONLY if the input shaft is swapped out. "F" series and "H" series engines use the same input shaft and the "B" series engines uses a different one.

 

[KY854RUN]

Yes, ONLY if the input shaft is swapped out. "F" series and "H" series engines use the same input shaft and the "B" series engines uses a different one.

OK, so what exactly is the diffence between F series and B series input shafts?

 

[cruiser_guy]

OK, so what exactly is the diffence between F series and B series input shafts?

One is longer than the other and the spline count is different. Trust me, I wouldn't have gone through the trouble to swap input shafts with the FJ55 when I installed a 3B if I didn't have to! It's NOT an easy job.

 

[KY854RUN]

OK, you can usually deal with the spline count problem by using a clutch disc with the same spline count. But, you are right, the length difference requires the input shaft to be swapped. The length difference wasn't mentioned in any of the earlier posts.

So, will the input shaft from the H42 fit in the H41?

 

[cruiser_guy]

So, will the input shaft from the H42 fit in the H41?

No! I believe the gear on the end of the input shaft is part of first gear. Since the H41 and H42 have different first gear ratios, they do not cross over.

The H41 is a non-USA/Canada tranny and unless you or the PO bought the tranny from someone like SOR you can be sure you have an H42.

 

[KY854RUN]

Yes, you are right that the gear on the input shaft is part of first gear and the odds are against being able to swap them. But, I know how Toyota does things and if they could save money on production by doing it, the input shaft of the H42 would be interchangeable with the input shaft of a H41 that was use with the H series engine. The only way to know that would be to have a Toyota parts man check to see if they are the same part number.