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-   -   73 FJ40, F engine/3spd Overdrive? (http://www.risingsun4x4club.org/forum2/showthread.php?t=14035)

TonkaToy 09-16-2010 03:26 PM

73 FJ40, F engine/3spd Overdrive?
Does anyone know if there is an overdrive unit out there for a 3spd? I am trying to make mine a little more 'highway-able' and I think an overdrive would be a good option but haven't been abel to find one. Spectre only has them for 4spds or V8 conversions.

RicardoJM 09-16-2010 04:23 PM

I'm not aware of one. How about some 3.7 diffs?

farnhamstj 09-16-2010 07:34 PM

Just run bigger tires. That's like overdrive.

MDH33 09-16-2010 08:50 PM

The best bang for the buck would be to swap in an H42 (or H55 if you have the $) and then regear. That will make a big difference over the stock 3 speed and the parts are all Toyota and easy to find. :beer:

Hulk 09-16-2010 10:34 PM

The old school was of doing an overdrive was a Fairey overdrive. They haven't been made in a while, but you still may be able to find one. They were made for three speed trannies and I think they were a bolt-in unit, since they were made specifically for the FJ40.

Whoa. I just googled Fairey Overdrive, and it looks like someone is making them new for Land Rovers. Might be worth giving them a call.

There's a whole thread on MUD about these units.

I've also heard of guys doing a Ford Ranger overdrive, but I don't know anything about it.

rover67 09-16-2010 11:56 PM

I had that Fairey overdrive in my '67 Series IIA. It really was sweet. the best part was that it basically split all the gears so you could cruise in 3rd "and a half" when it couldn't pull 4th and 3rd was an over rev type of gear.. It bolted on in place of the PTO cover and replaced the tranny output gear which made it easy to install.

I did understand that they weren't the strongest though... but I tourtured mine (as bad as you can with a 77hp motor) and it did OK.

made a cool noise when it was engaged too, and the extra lever was always fun. I wanna say I got mine from www.roversnorth.com but I could be mistaken.. it dosen't look like they sell them anymore.

TonkaToy 09-21-2010 05:12 PM

Thanks everyone for chiming in....now I am even more confused about which way to go. Ricardo, is regearing a DIY'able project? I have done jeeps before and the shimming about drove me crazy! Regearing was my original thought. A buddy of mine bought gear sets from Jim for hie 4runner and he said it was basically 'plug and play'. I don't know about the 40 though.
Farnham, I'm not sure if this was a serious solution or not! Everytime I have gone to bigger tires before, it kills the low end and that's the last thing I need and the main reason I have stayed with 31.5 tires on the 40.
Martin, the H42 is an interesting option too and one I think I could do myself (?). I am just not sure where I might find one and if it will bolt up to the F engine.
As far as the overdrive, Spectre has one but only for a 4spd. I have been looking around and it seems as though, even if I could find one, this might be pricier than I thought.
I do want to do as much on this myself as I can and need to keep on budget. Besides, doing the work myself is why I bought this to begin with!
Thanks again for the replies!

RicardoJM 09-21-2010 06:10 PM


Originally Posted by TonkaToy (Post 162739)
Thanks everyone for chiming in....now I am even more confused about which way to go. Ricardo, is regearing a DIY'able project?

The key is to get 3rd members that have the gear ratio you are switching to - all of the detail work is done. I don't recall the years, but the FJ40 came with 3.70 gears out of the factory for a time. Many want to switch to lower gears, so they pull their 3.70 and replace them with 4.88.

It would be a long day's work for me, well certainly something I could get done in a weekend. Others might be able to knock the swap in 4-6 hours. The rear end is very straight forward. The front is a bit more involved as you have to take everything off to get the axles out - but it is a great opportunity to pack the wheel bearings:D.

I picked up a set of 3.70 thirds that I was going to swap in, but have since put the project on the back burner and have the thirds up for sale.

TonkaToy 09-22-2010 10:26 AM

Well, I guess I need to figure out what size I have in mine first. I will try and get it up on a jack and give it a spin tonight. I was hoping I might find the right sets already set up, had no idea you would be the one to have them! I played with the timing a bit last night, like we were talking about. I advanced it some and it seems to have a little more pep. I might try advancing it a tad more too.
Thanks for your help. I'll get back to you on the gear sets. If they are the size I need, I'll take them.

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