The J20 steering box swap - whos done it?

I am in the process of getting a J20 box to replace my leaking one. I have searched on here and the general consensus is that its a direct replacement excep for an extra mount hole(to be ground off) and possible hose fitting mismatch( o-ring vs. flare type).

what about the input shaft? Does it match up to the XJ/MJ shaft?

Any other problems? I am going to reenforce the frame so that won't be a problem.

seach, you won't be able to find the J20 box anymore and will probably end up with a stock XJ box as they are a replacement part for the older J20's. Durango box is where it's at. I got you started, You do the rest of the work....

Funny thing you ask.... just last weekend I attempted the very same swap out along with a complete axle swap out. As you stated you have to make a spacer block that can be made out of steel as I did before hand for clearance on this bigger box. Had hoses, fittings and cooler ready for swap out. Ran into a huge problem with the input shaft splines on the J20 box not the same size as the short intermediate shaft coupler that attaches to the steering shaft. This shaft is about 14" with two different couplers. The stock box spline shaft measures roughly .70 od with aprox 30 splines and the J20 measure .80 od with 36 splines. Thru help from two Vets I have come across a coupler these companys sell that would attach to the J20 input shaft at $40 bones. What I want to know is can we purchase the two couplers and weld a straight shaft in between to make up this intermediate shaft. There is some small devise in between this stock shaft and I have no idea what it does. Maybe a cushioning devise for full lock???? Anyways.
Pm me your e-mail add if you would like a pix or two of the spacer block I fab'd for this project.
I'm not giving up on this project, but I'm still recouping from a very strenuous weekend.......

Weasel said:

seach, you won't be able to find the J20 box anymore and will probably end up with a stock XJ box as they are a replacement part for the older J20's. Durango box is where it's at. I got you started, You do the rest of the work....

Click to expand...

A) yes I searched - see previous post. the box I am getting IS a J20 box( piston measures 3.5" not 3".

Chippo - please send pics of the coupler to wadelang at excite.com