Four speed swap?

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Apr 20, 2003
I have a 74 fj40, that has a 1f motor and 3speed tranny and transfer. Whats involved in swapping a toyota 4 speed in. I want to keep my three speed transfer. Have any of you guys done this? And is it worth it? Thanks, Pete
You will need a transition gear (the 4 speed has a 16 spline output and the three speed has a 10 spline and the transfer case gears are cut differently). The transfer shift linkages are different and the bearing on the transfer input is also different. You may have clutch issues as well but I'm not sure as I've only been interested in the transfer end of things.
I would wonder what your objective is or your end result of having a four speed trans is? Are you thinking that you are getting an overdrive? Fourth gear is the same as third 1:1.
If you want a lower first, the work involved to gain less than 2.0:1 by installing the Toyota USA four speed would not be worth the time, considering the gains from a 420 or 465 GM trans, but it is all about what you intend to use your ride for.

If you are going to be off road with it, and or in the rocks, a non-USA Toyota four speed, or a 420 or 465 would be the way to go.

Just my .02.

Good luck!

I installed a 3-speed t-case behind the 4-speed/2F in my cruiser, it's easy for any one with any basic mechanical skills. To mate the 4-speed to your engine, you'll need a 4-speed bell housing, I believe it will bolt right up to your engine. As for adapting the 4-speed tranny to the 3-speed t-case, buy one of the adapter kits from TPI, or any of the other monster cruiser parts suppliers. I had to install the top cover from the 4-speed t-case onto the 3-speed case in order to use the 4-speed shift linkage/lever. I don't think the 3-speed clutch will work with the 4-speed tranny, I belive the 4-speeds use a diaphram style clutch and the 3-speed uses the "three finger" style. Hope this helps.
I'm doing this swap right now. But, I'm going from F/3spd/3spd to 2F/4spd/4spd. But many issues are the same.

Try the clutch, it should work. The input splines are the same betwen tranny's. You'll need the 4spd bellhousing and transmission. That end of things is really easy. Get a kit to bolt up the 3spd case to the 4spd tranny, as mentioned.

Drivelines will need to be lengthened/shortened to compensate for the extra length. Your e-brake cable may be too short, as well as your speedometer cable. You can get the ones from original 4spd trucks, or have them custom made at a shop that does such things.
OH yeah almost forgot: You already have ALL THE BEST PARTS that are required to put in an SM420 or SM465. If you're gonna wheel, consider those transmissions instead. If its a pavement pounder, then stick with the 3spd. The 4spd isn't THAT much different.
Thanks for the input guys. I do have a sm465 lying around. But I don't think that will give me to much lower of a first gear, would it? I will be doing normal wheelin with this rig, but wanted to crawl if I need to. I just haven't ever been a big fan of the three speed transmission. I'm just about ready to rebuild the f motor, do you guys think its worth the money and time, or just swap in a 2f? I'm trying to avoid a v8 swap, don't want to get that much money wrapped up in it. Thanks, Pete
465 is quite a bit lower. the toy 4spd is like 3.55 firstgear where the 465 is 6.55 I think. The 465s second gear is probably more like 1st in the toyota tranny. I'm in the process of switching to a 465 w/ 3spd t-case myself. That will give me a ratio of around 61 to 1 IIRC.
The SM465 is well worth it! Go for it dude you will like it. You will be able to go SLOW SLOW SLOW with that and the 3spd case.

If you can find a good used 2F, go for it. Otherwise there's nothing wrong with rebuilding the F motor. Except that for the same cost you can rebuild a worn out 2F motor ;)
I'm going SM420 for the reasons Toygeek listed. I already have the right transfer and bellhousing, and I need lower gearing. I was going to go to a 4 spd, but realized for about the same amount of work I could have a 7:1 first gear.
I had a SM465 laying around as well, but the adapters for it were going to cost more than 3 times as much as a Sm420 adapter. So I sold the 465 and several months later am still looking for a SM420. (Junkyards in cities don't keep stuff more than 10-15 yrs old)
When the time comes I will rebuild my F. Unless you get a 2F for free, there ain't nothin the matter with a F. Update ignition to FJ60 electronic, and you're set.
Do the 465 swap, you will love it. While the adapter may cost more, you will be using a trans that you can re-bearing and gasket for about 125.00, and if you need anything else for it, you will not have to purchase three 420's in order to possibly get the parts you need. I have a 420 in my Red truck, and love it, but if I did not have four complete, and two others in parts, I would have a 465 in there...

I would spend the monies on a 2F over an F any day, even having to give a few hundered for a buildable core...But I would look for a good running 2F, and re-ring and gasket it, have the head gone thru, new rod bearings, and you are good to go...

Or just get a RamJet!

Good luck!

[quote author=CruisinGA link=board=1;threadid=9157;start=msg80577#msg80577 date=1072464737]
Rebuild kits are $135 for a 420, Napa has the gaskets.
Problem is finding one..... :(

The other problem with the 420 is the fact that some of the hard parts, ie gears, shift dogs and springs, and syncros are hard to come by, and many are not being made any longer.

There are many of those trannies out there, you just need to get out into the back woods area of you country and drive around. You will probably find one very quickly. Most people that have them, do not know them as a 420, but an older chev 4 speed.

Good luck!
Just a few thoughts:

I really like the Sm420 and 465. Heavy duty and great for off road. On road you have basically a 3 spd tranny. The biggest gain out of using a toy 4 spd is having 4 useable gears on the road. the 3spd TC swap is a good thing to do.

If you are going from 3 spd tranny/tc to 4 spd tranny and 3 spd case one issue will be the linkage. You can fab it up or swap the nose cone and linkage from a 4spd TC onto the 3spd TC. To hook the 3 spd case onto the 4 spd tranny you need the switch over bearing, new gasket, oil seal all of which comes in the kits offered. What they do not iinclude are the 4 spd bolts that hook the TC onto the tranny. The 3spd mounting bolts will NOT work and need to be OEM bolts. Try to get them with the tranny if you go that route. Dont know about going SM420 or 465.

Skid plate will need to be modified.

Get the 4spd bellhousing. You can use either clutch but the dog arm will flop over to the PS so you will need the PS bellhousing Motor mount to mount the slave. You will also need to extend the hard line over the firewall. If you go Sm 420 etc.. you can ignore this step. Either slave will work but the 3 spd slave has a different hose thread pitch; CCOT offers a retro fit kit to avoid this as the early hose is NL avail.

A late model F motor is great to rebuild. A 2F would be a better option if avail but I would not put too much money into a core. Be very careful of used motors.
I do not believe in refreshing a motor with new bearings. The time and labour is almost the same as a full rebuild. it really sucks to do it twice.

A 350 is a neat option if it is what you want and your driving style calls for it. It does not make sense to hire it out as it will cost a pile of money to do right. If you want to do it do it yourself. It will cost almost the same but you will end up with a lot of cool tools and knowledge.

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