cj6 crossmember

so I have been trying to mock up my stock crossmember in a 70 cj6 with sm420/dana 300 combo. at this point I had to lower the stock crossmember about 1 1/2 inches. then I put spacers between crossmember and trans mount to give clearance to front t/c yoke. I still will have to run a small body lift and/or modify the tub between the seats (I really need to work on my metal skills).

 

How much lift do you have there?...........spring under maybe 3-4 Inches?..........Do you have a clocking ring between the Tranny and transfer case whereby you can rotate the TC up higher? If you can clock up , You may still have to put some drive line angle correction wedges at the rear springs.................More Pictures would help see what ya got!

 

yes a 3 or 4 inch spring under... I don't believe I can "clock up". driveshafts seem plenty long, (when compared to a cj5). also the t/c shifter bracket thingy would be hitting the trans. im more worried about front t/c yoke and driveshaft hitting the trans. or crossmember. here is pics of t/c.

 

In the first picture is that the adapter between the Tranny & Transfer case? ................Have you looked at Novak adapters site? look at there part #423 Lot's of good info there...........I'm just trying to figure out why your having that much issue with room under there that you need to drop your transfer case that much?......I'm sure it's easy to see from your view........but it's not that clear looking from here.

 

I "inherited" this from a friend with the driveline bolted together and installed except cross member. indeed the adapter is high. this set up is 1 1/2 inches taller (from trans mount surface) than a t90/18. (I don't have a t14 combo to check but ill bet its similar). however it seems that many of the 420/18 conversions ive read about put 3-4 shims at cross member/frame. that's 3/4 of an inch anyway. I gave an extra 3/4 so I could lift trans back up at cross member (about 3/4) to keep front t/c yoke away from cross member...whats left of the tub is about an inch higher than it would be, and the top of adapter/trans case are still almost touching it.

its hard to find much on a 420/dana 300 in an early cj. the ones I found seemed to fab new cross members...

i could make the frame spacers somewhere around 3/4 instead and modify tub to clear (possibly a good option since floors need repair anyway, wouldn't need body lift, a little extra ground clearance.)

I have read much at novak, AA, and other places. the info is great but the cost of replacing a working adapter for 2 inches in length and maybe an inch in height is prohibitive.

im way out of my league on this one, but ill bet i learn a lot by the time im done!

 

Yes you will learn .........and who said an education was free? .....The good news is that you already see some of the issues that you face.....take the path that best suits your needs & final outcome for the build and move forward! Good Luck.

 

FYI, when I did the NV3550 swap in my CJ-6 I retained the stock crossmember but rather than space it down I cut out the inverted U from the middle and welded in plate. Drilled a couple holes and used a GM auto tranny mount. The bolt heads were a little exposed, but I never had a problem even after dragging it over the Rubicon. That allowed the crossmember to stay up against the frame in the stock manner and not turn into a grappling hook on the trail.

It's a shame my company goobered up all the old stories we had uploaded to jpmagazine.com. I looked, but couldn't find it. Here's a photo from the trip just after making a trail repair at Buck Island campsite. I kinda mangled the stock crossmember on rocks and as a trial repair stick-welded in some plate steel. Still, you can kinda see (just behind the trail fix) the tranny mount mod that gives you a bit more clearance.

 

I bolted it up today with a couple "average" spacers. i like the overall angle of the drivetrain much better, which is probly the place to start. it seems to be roughly parallel to rear axle yoke (to my untrained eye) which should be a good thing. i see how you did the cross member, dummy, and if i modified mine to clear my front yoke more, that could help... one thing I don't really know is how much clearance I should have between front t/c yoke and cross member. the yoke spins right above the cross member and it seems a likely place for flex under load...

 

Just pulled my t14/t18 combo. There were two 3/16" x 2" x 4" (or so) spacers stacked on each side between frame and x-member. I can measure xactly if you want.


Fired my phaser at my abacus and it now hoses my grammar and spelling

69 Dauntless CJ5 - The Heep
Resto-Mod
(heep and jeep are four letter words)
http://www.earlycj5.net/forums/showthread.php?99079-69-Dauntless-Project-the-Heep

 

yeah, those are the "average" spacers i referred to. somehow i have a gang of them. (all this stuff builds up after a while) i don't like to use more than a couple, and i didn't think a couple would be enough at first...

 

im getting closer...front yoke less than an inch from cross member though (I may modify it a little) and I need to get the proper rubber mount for torque arm...