View Full Version : What auto should I put in my 40?

10-19-2006, 10:40 PM
What auto should I put in my 40? got about 1k to spend this is going to be 75% trail rig. what will be needed for the conversion? what rpm stall converter? should I put a different transfer case on? is it worth it to rebuild my tc or shound I just buy a heavy duty np231 for 350$?no I dont have the budget for an atlas. th400-350 whats the difference? please I need input thanks.
Or should I scrap that and do a 4spd and a klune v extreme underdrive david? I cant seem to find out what they run $$$ though?ooooooooooorrrrr!
convert to fj 4 spd trans and transfer case plus a rock box? anybody have a 4spd trans and transfer 4 sale?

Man Jerk
10-20-2006, 09:07 AM
What are you running for a motor?

If you are running a V8 that I would go with the 700r4. Good low 1st gear, plus overdrive. You can have it built real nice and strong. You can adapt your stock t case, but that would be the perfect time for an upgrade. Isotel here did a 700r4 with a Dana 300, and built a mini truck / cruiser hybrid axle for the centered rear diff. Lots and lots of upgrades for the dana 300. Or you could spend the ching and go with an orion.

If you are running a stock motor I'd stay away from an auto. Sucks too much power out an already underpowered motor. I can't even think of anyone who makes a conversion kit for the f series motors. Up and Over innovations or downy made one at one point, but I don't know if they do anymore. If you are running a stock motor, I would either go with an orion, or with a marlin crawler.

:thumb: :thumb:

Stay with the stock torque converter. Any lower and you will drive through your brakes.

10-20-2006, 08:17 PM
stickin with the f because this is not a highspeed vehicle and it has almost as much torque as a 350.

Man Jerk
10-21-2006, 05:51 PM
I wouldn't put an auto behind an F.

Why not put an SM420 in? Cheap to convert.

10-22-2006, 12:00 AM
i think im goin with a f-lc4spd-rock box from atlas-3spdtransfer. opinions any one? i am new to this fj scene please help

Man Jerk
10-22-2006, 11:10 AM
i think im goin with a f-lc4spd-rock box from atlas-3spdtransfer. opinions any one? i am new to this fj scene please help

I don't much understand your question.
I don't believe you can install an atlas in the stock drivetrain. 1st of all all atlas' need a centered rear output. (or did you mean rock box from advance adapters...I get it now). Yes this is a feasable option. How does the price of the rock box compare to the marlin crawler? What is your wheelbase at?

Here is another option for you,

No USA 4 speed with low 1st gear and the orion transfer case. Gets you good crawl ratio and basically a bomb proof transfer case. It would be quite a bit more expensive than 1k though.

10-22-2006, 03:06 PM
sm420/465 is the only way you are going to stay within your budget....

10-22-2006, 10:35 PM
yeah a sm would be cheaper but a rock box will give me 16 forward gear options and how can you beat that kind of versatility? plus as a wise man told me (drew) if I wheel with other fjs then the more fj parts I keep on the truck increases the chance that some one has a part to get me home. and the parts that come on these trucks from the factory are pretty tuff and reliable to start with (except the lft birfield read my fjs shakedown tragedy)

Man Jerk
10-22-2006, 11:29 PM
Getting some kind of rock box / crawler etc in there for less than 1k is gonna be difficult. You can always sell your blood right? ;)