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This second installment in the series of articles detailing the build up of my 1970 CJ-6 will cover quite a bit of ground. This article covers the mounting of the drive train on a rolling chassis. While the first article in this series was as much of an instructional rebuild guide for the Spicer 18 transfer case as it was a review article this installment is meant to show you where we are at in the build up, what parts have been chosen, why they were the parts that were used and how all of these parts work together. Hopefully each of you will be able to take a look at what I have picked as my ideal set up and use what I picked for my rig as either a blueprint for your own project or as one example of how you would not want your own rig set up.
My build up started years ago when I had a lot less experience and Jeep know how. I purchased my CJ-6 and brought it home. After a month or two of trying to drive it and poking and prodding the various pieces of the rig it became apparent that a frame up would likely be the best option. After the rig was disassembled I looked at the stock components and figured out that there was only a hand full of items that would be reused. These consisted of the body, frame, rear axle, transfer case, soft top (as it was brand new), OEM horn and hood. Every other component would either be sent to the scrap yard or sold/given away to people who could make good use of the parts. I knew that I needed to have a rolling chassis together to be able to do much in the way of putting my rig together so that is where I started.
The frames on pre-1976 CJs are an open C-channel type that is only boxed in the engine compartment where the motor mounts are located. This means that while you can gain some extra off road ability from the frame flex this type of frame is notorious for cracking. My rig was originally equipped with a power take off driven trencher (think ditch witch). These older units were massive and as a result the frame had a lot of reinforcement where the trencher bolted to it through the floor. I consulted Matt Peters at Peter's Off Road to fully box the frame from the front up to and a little past where the heavy duty ˝ inch reinforcement plates were located for the trencher conversion. To aid in stiffening the frame and to protect the passengers of my rig Matt built a 6 point roll cage using the front hoop kit from 4wd Hardware with the remainder being built from scratch. The cage was then tied into the frame using tubular and plate steel supports. He also mounted a new rear frame cross member and built a new front frame cross member and grill mount.
Once these modifications had been performed I could paint the frame and move on from there. The frame was painted using POR-15. One base coat was applied after which a coat of POR's Tie Coat Primer will be applied. Because of time constraints I had to apply the coat of POR-15 and then let it harden. Once cured you either have to sand the entire frame or apply tie coat primer to allow your top coat to adhere. My top coat will consist of a liberal layer of Rustoleum Gloss Black. I chose gloss because it is easier to get dirt, mud and grime off at the pressure washer and it won't be glossy after the first few wheeling trips anyhow. In the pics where you see the frame painted a blue color that is the tie coat primer waiting for a top coat.
After the improvements to the frame had been made I could move on to my axles. The OEM rear axle was an off set, 30 spline, flanged Dana 44. While I wish that the width was a bit wider the axle is plenty strong for most of the wheeling encountered on the east coast. The OEM gear ratio was 4:88 to one and I decided to stick with it although the factory gears needed to be replaced due to moisture induced pitting of the ring. I replaced the factory Trac Loc with a Detroit Sof-locker and had all of the bearings and seals replaced. The gear set up was done by Matt at Peter's Off Road. The OEM front axle was a Dana 27 closed knuckle model that was incomplete. Rather than sink money into this inferior design I opted to build a Dana 30 front axle. I bought a housing along with axle shafts, knuckles, hubs, and 6 bolt caliper plates from a buddy. I then proceeded to stuff the front end with all new parts including ball joints, u-joints, bearings, seals and brake parts. I had Matt install 4:88 gears to match the Dana 44 and called it a day. Once the axles were completed I was able to throw them under the frame using Skyjacker 4 inch lift springs and a set of .5 inch lift shackles from 4wd Hardware.
Once the rolling chassis was assembled I could start looking at laying in the drive train. In the 4 or so years that I have owned my Jeep the ideas for what engine and transmission would ultimately be used changed a number of times. The final selection was 305ci Tuned Port Injected Small Block Chevy V8 mated to an NV4500. While I was actually looking for a 4.3 V6 to power the rig I found out that a local Jeep parts supplier by the name of Dave Lesick had the 305 TPI motor for sale. The engine was from a 92 Camero. I found this particular year better for off road use because rather than utilizing a mass air sensor which can be prone to failure in damp off road conditions the engine used a speed density system to run the fuel injection which should prove more resilient for off road use.
The transmission was sourced from ManTrans, LLC based out of Tallahassee, FL. After deciding that an NV4500 was the transmission for me I looked high and low for a good used transmission or a rebuilt model to meet my needs. They are almost impossible to find in a yard and for a reasonable price. Mantrans can hook you up with a fully rebuilt NV4500 with a 12 month, unlimited mileage warranty.
There were two key factors that set Mantrans apart from their competitors. The first and probably most important factor is that they cater to the Jeep crowd. NV4500, NV3550 and AX15 conversions in Jeeps are something that they specialize in. As a result not only will they build you your transmission but they will be able to suggest which model and which adapters you will need to make the swap the easiest in your particular application. While I had already sourced adapters for this project that asked me to send down my transfer case adapter and when rebuilding the unit they performed the necessary modifications to the tail shaft and installed the adaptor before then sent the transmission up to me.
If you have not sourced your adapters they can get them for you through Advance Adapters. The other cool feature is that they can build the transmission with just about any option that was available meaning that the shifter can be the best of the four different types available for your particular swap and if you want the 6.3 to 1 first gear that is always an option.
Once the transmission had arrived I bolted the freshly rebuilt and upgraded Dana/Spicer 18 transfer case to it. This was accomplished via an Advance Adapters sourced transfer case adapter. It should be noted that the only way to be able to adapt an NV4500 to the Texas bolt pattern found on Dana 20s and Dana 18s is if you use a Chevy 4wd NV4500. At the other end the NV4500 is bolted to the TPI motor via an AA conversion bell housing. AA has several different options to make this union possible. The one I chose utilizes an actual clutch fork with an external slave cylinder rather than an internal sealed unit. The clutch master cylinder and slave cylinder used for this application are stock 4 cylinder CJ pieces. I felt that this off the shelf part would be a better alternative to something custom and having an external slave would certainly be something easier to fix on the trail than an internal slave cylinder should it go bad.
In addition to the adapters I had Advance Adapters send me one of their shift handle kits as well as an adapter mount. The adapter mount proved un-useable in my application because I could not use the stock cross member. If the Jeep you are working on is of the 76 or newer variety these adapter mounts would likely prove to be the ideal type to use with the stock cross member.
The 305 TPI motor was originally mated to a 700R4 automatic. As a result I had to round up a fly wheel. Rather than scrounge at the junk yard I just wondered from my desk on up to the counter in the 4wd Hardware show room. I ordered up the Hays billet fly wheel. In addition I was lucky enough to find a Hays diaphragm style conversion clutch in the special out section where display items and returns are sold. The only part I had trouble sourcing was a throw out bearing. Ultimately all three pieces, the clutch plate, clutch disc and throw out bearing, all proved to be from the same real world application. If you find you self in the same boat you will need clutch parts from a late 60s or early 70s Chevelle/Nova/Pretty much every Chevy muscle car with a small block Chevy and an 11 inch clutch. As a matter of fact if you wanted to source a parts store clutch rather than a high performance model you could go to your local parts store and request a clutch from that application.
Well that wraps up this segment of the build up. I hope you are enjoying the transformation. There is still a lot of ground to cover in the build up and steering, the fuel system and the braking system are next on the list of things to tackle.

Here are links to both Mantrans, LLC and Advance Adapters. Both are excellent sources for your Jeep build up needs.

In addition if you would like to contact Peter's Off Road you can

And if you would like to contact for used jeep parts or repairables click on the link below:

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