FJ80, 4BD, which tranny? (1 Viewer)

[Beau Diddly]

I'm in the planning phase of swapping a 4BD (probably the 1T, rather than the 2T) into a FJ80. I have a local mechanic who will do it, and he has a some experience with engine replacements in the FJ80, but never a diesel swap. My goal is improved MPG and longevity, hopefully my forever truck. In doing my homework, it seems most people want to keep their stock tranny or go with the NV4500. I definitely want the 5-speed manual with overdrive, but the NV4500 seems more than I need. Considering my goals, any recommendations on a tranny?

 

[cody c]

ZF42?

 

[longbow]

I would definitely go with the NV4500 if you are going to go with a manual tranny.

The H55f is not tall enough gearing in the overdrive ratio for a diesel with 4.1 gears like the 80 series and I don't think 5th gear is strong enough on that tranny. Flcruiser had one blow 5th gear going across country from florida in his FJ60 with a 4BD2T in it. He has since gone with a NV4500 and had no problems since. I originally did an H55f in my FJ60 when I did my original swap to 4BD1T and it just wasn't tall enough gears in overdrive. (.85 as compared to .73 for the NV4500).
The NV4500 is a proven tranny that can handle the torque of a diesel, just make sure the tranny you get has had the 5th gear upgrade. They had a problem with something that and I don't remember what it was.
The 4BD series diesels are great engines and a heavy duty industrial design. Whatever tranny you end up going with, make sure it is extremely heavy duty because the 4BD engines have some serious torsional pulses from only being 4 cylinders.

Good luck with the swap!

Don

 

[Beau Diddly]

I would definitely go with the NV4500 if you are going to go with a manual tranny.

I'm reading the Isuzu 4-speed and 5-speed manuals had the same final drive ratio, so the 4-speed is a better option of the two. I've also read the NV4500 gear ratio steps are not well suited for 4-cylinder diesels as many have learned the hard way, therefore the Isuzu 4-speed manual is the best option for the 4BD. I'm a new guy planning my swap, so I'm not speaking from experience, just trying to learn and reconcile these different schools of thoughts. Thoughts? ...and thanks in advance

 

[Beau Diddly]

Sorry, I botched the above post. The first sentence was Longow, the second paragraph was my response/question.

 

[VETTE60]

nv4500 or the ford ZF.

 

[longbow]

Flcruiser is running one and he likes his NV4500 behind the 4 cylinder isuzu. I don't think any of the USA Isuzu manual trannys that will bolt up to the 4bd series engines ever had overdrive. Non-USA Isuzu's got an overdrive 5 speed but even if you find one you have to build an elaborate linkage system to shift them due to the tilting cab of the Isuzu trucks. NV4500 would be my choice or I do like the ford ZF tranny as well if you can figure out how to adapt one.

Don