I am reposting this question because I did not get very many replies last time, hoping that more listers will see this time.

I am collecting parts for a SM420 conversion. I have been told I must use a 3 speed transfer case to mate properly to the plate style adapter that I have.I was told that someone makes splined transfer case gear that will allow the use of a 4 speed transfer case. I would like to use my 4 speed t-case as it has been newly rebuilt. her is a pic of the adapter I am using . Anyone know of a vendor that can help with that application?

I was told that you can take a 3 speed input gear and put it into the 4 speed case and it would work. But I never actually tried it. I used the 3 speed case that I had.

All you need is a ten spline input gear. Maybe someone has one you can try??

I was under the impression that you needed to use a 3-speed case because of clearance on the smaller yoke for the front and if you had the smaller output flange from a 3-speed you could just swap it onto a 4-speed case??

:confused:

I have a 3-speed case so I don't really know.

Glo',
The 4 speed case is a 16 spline isn't it??
I would think that just changing out to a ten spline would solve it .....but it can't be that easy......................


Mark,
the adapter I got is a extreme bends clone and is clocked so the front output requires no grinding on the 420 case. I may have to turn down the flange slightly, but thats no big deal. I'm just want to make sure I can use the 4 speed case by changing out the gear.


thanks for the reply

Originally posted by bennett
Glo',
The 4 speed case is a 16 spline isn't it??
I would think that just changing out to a ten spline would solve it .....but it can't be that easy......................



Yeah that's what I thought too, that's why i stuck with the 3 speed case for now.

How far is that thing clocked? I have an Extreme bends style adapter and I had to grind the shit out of the tranny and turn down the flange to get it to work. :confused:

3 speed and 4 speed gears not only have different spline counts but they also have different angles on the teeth and are different thicknesses.
I don't know of a gear with the 4 speed outside and 3 speed internals. There is the transition gear from 1974's that has the 4 speed internal splines with 3 speed outside but that won't work with this installation.
The Extreme Bends plate requires no grinding to the tranny. There are other plates out there that require grinding to the tranny. The Extreme Bends plate is rotated which means you need to re-drill the holes in the rear wing when retro-fitting V8 kits. There is a rotated rear wing available for V8 conversions.

You're stuck with the 3 speed case at this time unless you want to go to a SM465 plate kit made by a few other companies.

I would like to know if any finds a supplier for a gear with 10 splines and 4 speed outsides. I'd buy a bunch!

Steven@extremebends.com

Once again. How far is that rotated? I don't see how you can rotate it down far enough to not have to grind on atleast the yoke?? :confused:

How far is it rotated??
Lets say approx 10ish
I would suggest cleaning the burr off the flange from when it was stamped out, that should give an EXTRA 1/16" to the gap. I have a few pics of the clearance between the flange and tranny at home, I'll send them to the list tonight if anyone wishes to see them. The pics don't show a lot of detail just the clearance gap.
A few degrees rotation does make a big difference to the amount of grinding some plates require.

Steven@extremebends.com

Originally posted by Mud Guppie
How far is it rotated??
Lets say approx 10ish
I would suggest cleaning the burr off the flange from when it was stamped out, that should give an EXTRA 1/16" to the gap. I have a few pics of the clearance between the flange and tranny at home, I'll send them to the list tonight if anyone wishes to see them. The pics don't show a lot of detail just the clearance gap.
A few degrees rotation does make a big difference to the amount of grinding some plates require.

Steven@extremebends.com

Yeah Mud, please post some pics or e-mail them to me at

bennett@networld.com....

PS.......any idea on the 4 speed tcase question ?

thanks

The bolting pattern for a 3- versus 4-speed are identical, the only difference you need to be concerned with is the difference in spline count on the input gear. There is a gear available from 1974 Cruisers that matches the 16-spline input of the 4-speed with the tooth count of the 3-speed internals.

However, AFAIK, there is no 10-spline input gear that matches up with the 4-speed internals.

In other words, yer stuck needing a 10-spline input transfer case.

If you can find a 3spd transfer case (probably $100 or less) you can just swap the input, idler, and high and low gears from the 3spd case to the 4 spd case. That would give you lower gears (10%, if I remember correctly), give you a structurally stronger 4spd case with rebuild, and the correct 10spl. input for a the plate adapter. You would also need to replace the shims that ride on either side of the idler gears (on the idler shaft) with thicker ones, available from Toyota.
If you can do it yourself (and you can!) it is an easy swap. :D :D :D

Where do you guys find these $100 3 speed t-cases? Everything I see is $250+ and not rebuilt!

Originally posted by Mud Guppie
I don't know of a gear with the 4 speed outside and 3 speed internals. There is the transition gear from 1974's that has the 4 speed internal splines with 3 speed outside but that won't work with this installation.


Actually, there is one I know of... definately not a factory thing though.

Originally posted by Mud Guppie
You're stuck with the 3 speed case at this time unless you want to go to a SM465 plate kit made by a few other companies.


See above.

Originally posted by Mud Guppie
I would like to know if any finds a supplier for a gear with 10 splines and 4 speed outsides. I'd buy a bunch!


Do I get a finders fee? :rolleyes:

There is one company I know of that has a custom made 10 spline 4 speed size gear. That company is Classic Cruisers in Colorado. Last I recall, the cost was $125 to $150 a gear.

However, if they do ANY work on the gear, I wouldn't trust it.... just a disatisfied customer of their plate(cloned and returned after two bad plates being sent out) and SM465 output shaft.

There is a very large gear manufacturer in my area and I do plan on making THE GEAR. But that won't be for a while. If there is a demand for it I will move it ahead on my DO list. I think the gear will be great because you can run the quieter and easier to find 4 speed T-case. Just remember the SM420 isn't the quietest tranny around.

Steven@extremebends.com

Hey Steve - What happened to my quote for 60 axels???

:flipoff2:

Mark, your quote will come to you off list.

The clearance picture is not the greatest, the measurement with NO GRINDING on the tranny is close to 1/8" and that's without cleaning the burr off the flange which would give about another 1/16" or so. If you wanted extra clearance you could always take a bit off the corners of the flange.

Steven@extremebends.com

Lil John is correct, there is a ten spline gear available for the 4-speed transfer case. I'm using one currently, the box said SEABass on it-made in Japan.
Note, I bought mine from company Lil john mentioned however I believe a fellow in the Southern Nevada Landcruisers club sells them as well (forget his name).
Anyway, you can run a plate style adapter with a four-speed, is it worth it? . Note , my front drive-shaft utilizes a small 280z u-joint /yoke? to get clearances, Or at least it will unless I run into a better drivetrain setup.

I'm interested in that gear.
There is no point re-inventing the wheel.
I'll look into it more.

The only problem would be clearance for the front output flange. The older style 4 speed t-cases are not fine spline so you could shove a 3 speed flange on it, but the newer 4 speed t-cases are fine spline so there would be a fit problem. You could always run the nose cone off an older 4 speed and use the 3 speed flange.
No biggie, it can be done.
Or you could just run the 280Z stuff if the Cruiser parts are too hard to find in your area.

Steven@extremebends.com

bennett,
The adapter plate you got from me is not an extremebends clone. More of Warden's with out the clocking. I have referred many to the extremebends web site for a look at John's excellent install write up, hence the confusion.

I did install mine without grinding the tranny by using the 3spd flange and turning the flange and u-joint yoke down on a lathe. Finished outside diameter was 3.80". That will get you about .075" clearance, not a lot but no interference. Unfortunately it means no ready spares from other rigs.

I wasn't aware of a gear that was available for the 4spd tcase, this is good news and I hope it is true. Somebody post the results of their call on this, please.

Steve,
It is good to hear from a source on these types of questions. Thanks for participating. I'll be sending an e-mail to you when I get done here on a related subject.

Mike "SpaceGhost" Smythe

On my 420 project, I am using the 4 speed case for strength with 3 speed internals.
Everything lines up great on the bench...
I do still need to visit the local dealer and get the thicker idler shaft shims as the clearance is too much.
No big deal. I will also turn the flange or grind the tranny case or a combo of both.

Cory

I have a 4-speed t-case from a '74 cruiser with a production month of Sept. Are you guys saying that I could take the input gear from the 3-speed t-case that is currently behind my sm420, (plate adapter used to mate them) put it in the 4 speed case and everything will match? That would be great to get the lower ratio and stronger case that easily.

74 is a change over year...
Some 74's have a 4 spd with 3 spd t-case splines IIRK

Otherwise, you CAN use a 4 spd case and put 3 spd inners in it. With the shim mods for the idler clearance. This is for SM420 set ups. If you retain a 3 spd tranny (why) then you also need a new bearing in the back of the t-case (the one you removed and threw away when going 420)

Cory

Just counted revolutions on my '74 case and its a 1.99 to 1 ratio. :crybaby2: