Subscribe to a magazine

September 2011 Nuts & Bolts

Willys Cj2a Chassis
Fred Williams
| Brand Manager, Petersen’s 4Wheel & Off Road
Posted September 1, 2011

Your Tech Questions Answered!

I Broke My Willys!
I have a ’48 Willys CJ-2A that I have been building for the better part of eight years. It started life on 31-inch Wildcats and moved up to 33-inch BFGoodrich mud-terrains. Currently it sits on 37-inch Goodyear Wrangler MTRs. I swapped out the axles first from a 41 rear to a 44 rear. It now has full-width, 30-spline Dana 44s front and rear. The back has been welded solid; the front remains open. The drivetrain is a Chevy 283ci V-8 bolted to a Muncie 4 Speed adapted to a Dana 18 transfer case.

Upon completion, I tested it in a buddy’s field and found an old car and climbed it, breaking the adapter between tranny and transfer. I was wondering if there is a place that sells used adapters (due to lack of money) so I can get it on the trails again. Or maybe you have some good transmission replacement ideas that will remove the adapter all together.
Branden C.

I also have a late-’40s flatfender with a 283, a Muncie SM-420, and a model 18 transfer case. After scraping years of mud and grease off my adapter, I found that it’s from Advance Adapters ( I do not know of any sources for used adapters, but I would suggest you clean your adapter and figure out who made it originally. I know at least Advance Adapters and one other company, Novak Adapters (, make the SM-420–to–Dana 18 adapters. I’m sure one of them would gladly help you replace what you have broken.

The Dana 18 was available behind the T-98 four-speed Jeep transmission as another option, but you would then need to adapt that to your GM V-8, so I would just find a new adapter for what you have.

I would also be concerned with why it broke in the first place. Did the driveshaft bottom out and push the transfer case upward? Did the crossmember mount under the transfer case get bent while car-crawling? Or was it simply a manufacturing flaw?

Arms Need More Reach
I am building up a ’77 Ford F-150 shortbed stepside. I have upgraded the drivetrain from a C6 with a NP205 to an NP435 connected to a NP205 and then rebuilt the motor. When I started to drive it and get onto harder trails I started to see that the suspension falls short in a few areas. Then on one of my wheeling trips I heard a loud pop come for the front end while it was flexed to its absolute max. As soon as I had all four tires firmly planted on solid ground I got out to conduct damage inspection. I was surprised to see that the bottom two bolts of the driver-side radius arm had snapped clean in half. I replaced them, but after three wheeling trips it snapped again at full flex, but this time the other side went.

I obviously need to fix the problem, but how would I go about doing so? Do they make radius arms with flex joints on the end instead of standard bushings? I would like to be able to fit 38-inch tires, so should I buy extended radius arms while I am at it and a lift? I just want it to be able to flex out without binding. Thanks for the help.
Stew R.
Sandy, UT

When you lift your truck and flex the suspension you place serious bind on the stock radius arms. Radius arms are a great suspension system in controlling axle twist under acceleration, but not the best when off-road. One good upgrade is using longer radius arms. Many companies offer these, such as James Duff (865.938.6696, The longer radius arms require new frame mounts and at least a 3-inch suspension lift. James Duff specializes in early Broncos but also offers parts for many of the late-’70s fullsize Broncos and F-150 trucks. Another company that makes long tubular radius arms is Bloody Knuckle Garage (360.460.7579,

Imported From Detroit
Recently I destroyed the ring-and-pinion in the rearend of my ’58 Studebaker pickup. It has ’73 Dodge Power Wagon running gear from a W200, so it is a ¾-ton, and the rearend is a Dana 60. I know I have to get a new set of gears, which are 4.10s. But I have to take it all apart anyways to put a locker of some sort in it. I currently have 33s on it and drive a good mix of street and mud.

I was leaning toward a Detroit Locker, but I was wondering if there are similar lockers I could use. Also, when I searched for a Detroit I had a couple options: a Dana 60 Reverse or just a Dana 60. Both of those had different spline counts on them. How would I figure out what the spline count is on my axle so I could get the right locker? And do you know if I need a Dana 60 Reverse locker or just a Dana 60?
Douglas City, CA

Your rear axle mostly likely has a full-floating hub design. This allows you to unbolt six or eight bolts on the hub and slide out the axleshaft without disassembling the entire axlehousing. In fact, you can do this without removing the tire and wheel. But be sure to raise the side of the axle that you are working on with a jack and a jack stand to keep the gear oil from running out. With the axleshaft out, you can count the splines. The axleshaft could have 19, 30, 32, or 35 splines.

The Detroit Locker ( is a great option for your truck. They are strong, and unless you have an axleshaft failure where the shock load can sometimes damage them, they rarely fail.

Yukon Gear ( has a very similar locker known as the Grizzly. It was recently released for the Dana 60 market, but I have not yet tested these, so I do not know how they compare to the classic Detroit.

You axle is definitely not a 60 Reverse, as that was only used in Ford front steering applications. A reverse or reverse-rotation axle is also known as a high-pinion.

Short Willy Dilemma
My wife and I have a ’55 Willys. We want to do what a lot of people do and transplant a newer drivetrain into it. We have a line on a Chevy S-10 with a throttle body injection (TBI) 4.3L and a 700R4 automatic transmission. I know there has to be a way to hook up just the engine computer and transmission controls without the entire wiring system of the S-10, yet still keep the Willys inner harness. Can you point me in the right direction please?
Gary D.

You need to talk to the people at Howell Engine Development (810.765.5100, about the wiring harness for the 4.3L. The 4.3L V-6 is a great engine choice for a Willys Jeep, especially in a flatfender Willys or CJ-5. The 700R4 may be a problem depending on what model Jeep you are building, as it is very long and the CJs of that era are pretty short-wheelbased. Advance Adapters (800.350.2223, can help you with all your adapter needs and with other transmission options if you are planning on putting the engine in a short-wheelbase vehicle.

Load More Read Full Article