I own a '95 XJ Country, and it has a 242 in it now. Instead of regearing, I'm thinking of a 231 doubler incorporating a 241 from Chevrolet. Is this a good idea? I'll have to put in a SYE in it also. Will the stock Jeep speed sensor fit in the Chevy output? Is this a valid idea for a daily driven rig that sees a lot of freeway time? Trying to cover a lot of bases for a minimal cash outlay. Who makes the most cost effective unit? Ease of installation? I talked to a fellow a couple of weeks ago, and he seemed to have it all together. He was going to install his unit soon. Just trying to cover all the bases. Any help would be greatly appreciated. Thanks, poppajeep

 

Why do you want a doubler? Are you in an auto or stick?
First, if you are in an auto, I would definitely not agree it is worth the time. With a stick, it is great to have the options, but will be a lot of work.

Most the doublers I see use the front of a 231 for a reduction box and a D300 for a twinstick case. Unfortunately, I can't shed any light on the compatibility of what you have. I can say the set up will be heavy, and long. The length will put the driveline at a sharper angle, and the weight could hurt your MPG a bit and will require some extra support. The MPG shouldn't be a huge thing, and the DL angle will be managable.
I have the Atlas 4sp, so basically the bought and much easier to install version of a doubler. With a stick shift, it is great to have the gearing options in crawling situations.

In short, if you want to do a doubler, check out some write ups on D300 projects, or save up for a Stak 3-speed or Atlas 4-speed. Or do whatever you want, and do a write up on it.

 

i will be doing a 231 to 300 with box4rocks or mad rooster kit. there are a few out there that have everything you will need.
you may have to cut the floor up a bit and box it in.

i wouldn't bother doing this with a dd or ww tho. it's a lot of work and can be expensive.

 

The doubler kit is for a NP231 to either a D300 or another 231. Here is a pic of the case.



There is a weld required. So anyway, you probably cannot use the 241 case from the Chevy because of the input spline count. It needs to be 23.

So is it a good idea? Sure! It will give you a three speed tcase and much lower gears and not hurt your highway performance a bit.

 

Lots of info to digest. Thanks for the responses, I appreciate it. Its like the manufacturers couldn't agree on a spline count, they're all different. Thanks again, poppajeep

 

Lots of options... I am suprised one option wasnt put pout there. A dodge np203 to a flipped d300. Yes you will need a clocking ring for the 203, but nearly bullet proof. You would also have to build a stout mutiple mount trans/t-case support. You will also have to clearance the floor a lil. Just so ppl know the np203/d300 is only 1/2" longer using the Jeds machine doubler setup. Add a set of tripple sticks.... and you are golden