Ok, my dad has a 1970 FJ40 with a 2F and 3 speed drivetrain. We are looking at swapping in one of the two transmissions (SM420 or SM465) to get a better crawl ratio (everyone knows the 3 speeds ratio sucks)

I want to get some peoples opinions on which one is better, pros and cons. Are either of them syncronize......etc...

I know the SM420 can have a slighlty lower crawl ratio, but his rig sees alot of pavement so we are also looking at road manners of the transimissions. Any input would be appreciated.

As far as performance I would say the two tranny's are basically the same. The 465 might be a smoother quieter choice.
The 465 is more readily available and parts are easier to come by.
With that said though there is a lot more work involved with the 465 then just bolting up the plate adapter.
Check out www.ih8mud.com for write ups on installing either.
I went with the SM420 but thats because I had it to use.

Id say go with the 465 its a much newer tanny than the 420, the road manners on both of these trannys is gonna suck because they are a three speed with a granny gear they will just shift very rough and slow

The SM420 has the lowest first gear, quite a bit lower than the 465. Coupled to the three speed transfer case this combo will give you the lowest crawl ratio.
Road manners ? I've been running a 420 in my Cruiser for a few years now and I have no complaints, it shifts just like any other truck four speed.

The conversion is going to be a lot cheaper with the 420, it's a shorter tranny, there are inexpensive adaptors availble and chances are you won't need to change the length of your drivelines.

Parts availibilty ?? All the bearings, seals and synchros are still availible. If you start out with a decent gearbox you should have no problem. The SM420 was designed for heavy trucks like upwards of one ton or even more.
It's a frickin bullet proof tranny.

A 420 is a louder tranny, but that's what they built stereos for , eh ?

That's my 2 1/2 cents worth, but then I'm a die hard SM420 fan.

I say the 420. MUCH easier conversion and both have 1:1 in the end (4th gear)

The louder the tranny, the tougher it is.

I think 420's are cheaper and easier to find than 10 spline 465's.

I did a 465 a while back and I would not recommend the conversion to the TLC transfer case.

If you want a 205 transfer, then the 465 will be a better choice, otherwise do the 420.

If you can find a 420 do it no question the adaptors to mate it up are cheaper and the finished package will be significantly shorter which becomes a major consideration when lift is added to the cruiser

As far as adapter plates....are there any companies to look at besides Advance Adapters? Who makes the best/cheapest adapters???

Also....is the SM420 syncronized??

First gear is not synchroed, top 3 gears are. It is basically a 3-spd with a granny low gear. I don't think the first gear in the SM465 is synchroed either, but I'm not really sure.

Spaceghost on this board makes them http://www.iei.net/~msmythe/landcruiser.htm
so does
Wardensautorepair.com
and extremebends.com
there are probably more. Go to ih8mud for more info.

If you are undertaking this project you might as well go as low as possible.

I run a boneyard 420, not rebuilt, just cleaned.....runs fine

I agree! Get the spaceghost plate. I am putting one on right now.

You can't beat Spaceghost's price, I think his plate is a hundred bucks and I'm not sure what he's charging for the hardware kit. I sure as hell know it's a lot cheaper than anybody else.

I just bought one for my nephews project rig and I'm very happy with the quality.

You didn't say what motor your running, but a 465 with a chevy v-8 can be set to keep the transfercase in the same place so no drive line mods are needed, but I would not let 150 in drive shaft mods make my choice for me. I'm a fan of the 465 and I used the aa adapter. I used the turbpo 350 tranny mount location for my cross member and have had zero problems. I have been in both a cruiser with a 420 and a 465 and have found the 465 to be quieter and smoother to shift. That said by the one you can get the cheepest and go for it. :beer:

i have a question also. (slightly off topic)

i currently run an H55F but i want/need lower gearing and i know they make geering kits for it (who is it again) but arn't they expensive and not that low?

now back on topic

I also run a chevy 350 and i have been thinking about the 420 now because i want a center rear diff and better gearing. If i was to switch to a 420 would it just bolt up to my 350 with the stock bellhousing or would i need an adapter. what would i run for a transfer case(that i can gear down) and what would i do about a cross member.

as you can see i don't know much about the different tranny and x-cases.

thanks, and sorry for getting off topic

You would have to run a different xfer case other than the TLC case. Since its offset.......
The only downfall to the 420 is getting hard parts, like gears,shafts, etc....They don't make them anymore and they are getting harder to find......:skull:

Originally posted by ranger
You would have to run a different xfer case other than the TLC case. Since its offset.......
The only downfall to the 420 is getting hard parts, like gears,shafts, etc....They don't make them anymore and they are getting harder to find......:skull:

yeah but what is the likley hood of breaking the gears or shafts, or even wearing them out (rig is driven so little)

Well as they say....Sh!t happens.................:skull:

Originally posted by wngrog
I say the 420. MUCH easier conversion and both have 1:1 in the end (4th gear)

The louder the tranny, the tougher it is.

I think 420's are cheaper and easier to find than 10 spline 465's.

I did a 465 a while back and I would not recommend the conversion to the TLC transfer case.

If you want a 205 transfer, then the 465 will be a better choice, otherwise do the 420.

What did you not like about the 465 to LC Tcase? I used a 2WD 35 spline 465 to LC case and I did not see a problem and it has been in there for 2 years and still good. Just wondering. You can find 2WD/4WD SM465s for really cheep I would not pay more than 150$ I got mine for 80$ and I love it not to noisy awesome first gear, 35 spline output, bulletproof, newer. I like 420s but they are getting out dated and harder to get .