[mdmike]

Here's the deal. I've got a 4bt going in a CJ-7. When I bought the motor, the previous owner was nice enough to throw in the TH400 auto tranny as well. My first idea was to scrap the auto and find a NV4500 out of a Dodge with the 6bt, but they are few and far between around my area, not to mention very expensive. I got to poking around on advanced adapters web site and found an adapter that goes from the TH400 to a Dana 300 (stock transfer case) for around $500. My question is, with 4:10 gears and 35" tires, what could I expect for a top speed? I would be installing the 3200 rpm governor spring in the pump, but I don't want to be running the motor over 2k rpm's for a long period of time. Also, the factory adapter from the 4bt to GM transmission clocks the motor 10 degrees. Has anyone split the difference between motor mounts and transmission mounts to lessen this angle? This Jeep will be seeing a majority of street driving with not a whole lot of offroad time, and I'd really like to be able to keep up with traffic on the highway. So, what do you think, am I crazy for wanting to give the auto a try? Lets hear it!

MIke

 

[64fordf1004bt]

Using a gearing Calculator at http://www.4lo.com/4LoCalc.htm at 2000rpm's with 4.10 gear and 35's you would be going about 50mph. Now if you switched to 3.25 gears you could run about 64mph at 2000rpm. If you want to keep the low gears I would suggest finding a overdrive transmission. :smile:

 

[bcowanwheels]

yyou need to be running 65mph at 1600rpm,s

 

[scout4bta]

3.54's and 38's would work:tongue:

 

[BigWheelBob]

I used 3.54's with a 350 trans, and 35 inch Pro Comp tires, in the last Jeep I did. The 4. 10's didnt give it enough road speed.

 

[mdmike]

Back to the top again. I've come across a 700r4 out of a late 80's early 90's Chevy 2500 with the diesel engine that I can get for free. Would this be a viable option instead of the TH400? I'm assuming the transmision would bolt up to the adapter I already have and since it was from a diesel application, I'm assuming the transmission is built a little more "heavy duty" than a standard 700r4 (?) I don't think the transmissions from this vintage truck are computer controlled so that would make life a little easier. Am I beating a dead horse here? Any advice is appreciated!

MIKe

 

[dieselcruiserhead]

I think that would work but the 700R4s, even behind the gutless 6.2s & such, were not very strong.. There are odds, maybe, that you might have to pull it out at some point and get it rebuilt or replaced.. It you want to put money into it, there are a few places that rebuild for anywhere from $800-$1300 I've seen for some super performance versions that hold up..

 

[JBox_Johnny]

i have a 700r4 in my cj7 it works very well...
i have 331 rear gears and at 55 i'm at about 1500-1600rpms...
i have the advanced adapters 300case to the 700r4 that also is just a bolt on...
the angle of the motor you are going to want to stay because the clearence from the oil pan to the front diff is close you are probably going to have to put a lift in...
i put in a 3inch lift and a about a 1 inch body lift to clear hood with the aftercooler...
even with the 3inch lift it gives me about 3inches from the oil pan to the front diff...
it drives very well and nice daily driver just a little noisy i guess....
you will need a sound bar:smile:

 

[littleman4542005]

iv got an 85 chevy with 38.5 tires and th400 and i can rund 75 and 80 mile per hour on interstate easyly. iv got 308 gears.