V6 225 Tranny options

Hello Everyone,

Slowly tearing down a '47 CJ2A and acquiring parts. I have decided to go with a Dauntless V6(lucky find). Now, I am trying to decide on what tranny to use.

Basically, I am going to drive this jeep on the street with some moderate off-roading. Just a good all around I hope. Right now the stock tranny is in the CJ, but I have come across a SM420 in good shape from what I am told. What to do? Any guidance?

Thanks

 

(1st Non answer)

It's up to you. The 420 is a good tranny, but you'll have to buy adapters for the tranny/T-case. Then spend some$ on making driveshaft mods sue to the different length of the trannies. More mods to the floor for the shifters, and then the crossmembers to hold it up. Clutch will have to be changed out along with new/different linkage for the clutch pedal. Not trying to discourage you, just letting you know what is involved. On the other side of the coin is the fact that you will have a 4 speed with a great low gear. Using a truck 4 speed was the best mod I have done over the years.

The easy/cheap answer is to modify/adapt the T-90 that you probably have now to the V6. It is a pretty decent tranny, just without the low 1st gear of the 420. Look it over inside and out, because they are prone to having 2nd gear issues. Lots of people, including myself have done tons and tons of "moderate off-roading" with the V6 - t-90 combo and it works well.
Ultimately it is up to you. Good luck and once you decide on a specific direction, I'm sure we can help out some more.

 

im doing the same conversion , you do need the adapter for the tcase which will lengthen your driveline ,, but the good news is if your willing to make your motor mounts you can do as i am .. The 225 is really short in length so I am moving it forward to where the 18 will be in the same spot , and it seems i still have plenty of room till the radiator and easy clearance of the firewall,, the shifter on the 420 is only a bout 3 inches ffrom the firewall so it will need a couple of bends but that is the easy part ,, all in all if ive measured all this right,, it s going to work well,, Ill let you know and take some pictures im droping it this weekend

 

Plus if you want an overdrive finding one used, that will fit, is a bit easier if you stay T90.

 

The overdrive is a non issue, as the the spud shaft (if you use Novak's kit for the adapter) allows you to use the stock bull gear. My business partner put the SM420 in his '70 Dauntless and had no problem bolting in his OD. Also, unless you have the bellhousing to tranny adapter as part of your V6 package, you'll have to hunt down an adapter to use the T90 with the V6 anyway. The SM 420 has the lowest 1st gear you can get in a 4 speed. It's roughly equivalent to 1st gear low range with the T90.