Axle Swap Maybe?

I'm in the process of building/rebuilding a 1967 CJ5, turning it into a CJ6 (a long story I plan on posting in the projects section). Everything has been removed from the frame and I am in the process of fixing cracks, holes, etc. on the frame. I'm thinking ahead to the axles.

My axles are the stock (no locker) 1967 Dana 44 rear and Dana 27 front, 3.83 gears. I have not begun to open the diff to inspect--and I've never rebuilt a differential before I should add. At the very least the seals/gaskets need replaced, especially on the knuckles which are caked in inches of grease and grit. I want to run a 4 inch lift and 33 inch tires. I know to safely have the 33 inch tires I probably need to convert to disk brakes.

I should also note that the T86 was trashed (no surprise from what I have read) and I have procured an sm465.

My intention for the finished project (God willing) is to do some light mudding and once a year go up on the sand dunes of Silver Lake, MI, otherwise it is a fun vehicle to drive in the spring/summer months.

Now for the question: I know there has been lots posted on swapping a Dana 30 in the front to replace the 27, but gear matching is always the issue with the rear 44. Would you recommend swapping out both axles? If so, what year and model for my intentions with the Jeep. Looking forward to hearing your two-cents worth. Thanks.

 

My 2 cents.

There are members running drums and 33s, I'm sure they can chime in. As someone running 11 inch drums front and no longer functioning 9 inch drums rear on 29 inch tires, I have no stopping issues IMO.
I imagine you may want discs due to their more efficient self clearing properties and easy maintenance.
But there is nothing wrong with drums unless you spend most of your time in deep water or mud.

Swapping both axles is a lot of work and probably not necessary unless you have a lead foot.

If you have a relatively light foot you can run 33s on the stock D44 with 3.73s (stock gears), but I doubt it would be easy to get it moving. 4.88s or more are probably going to be needed. The D44 rear can be converted to full float for greater strength. I know the D27 is no toothpick, but I have no experience running 33s on one. The later CJ D30 gives you about 8 feet total shorter turn radius, and has more simplified maintenance, but AFAIK, the D27 may be enough.




My advice is this, if you like originality and others say the D27 is good to go, keep it.

If you need/want more gear choices, or need some sort of front locking differential, go with the CJ D30.
Take the D44 and rebuild it into a full float D44. You can either have drive flanges on the rear, or hubs. Plus, you can use 30 spline axleshafts and use a modern locking differential or limited slip. Or even keep the 19 spline shafts and use a Powr-Lok.

 

The simplest solution might be to find a pair of axles from an intermediate CJ.
D30 front, and a D44 rear. The rear axle on these have stronger 1 piece axle shafts. The rear diff is centered, but that won't matter on a long wheelbase rig.

 

An intermediate Jeep ('72-75) will have a 3.83 rato standard, and 4.27 optional. The 4.27s are more desirable, but the 3.83s might be more suitable for you if you go with the SM465. An intermediate has 11"x2" bendix drum brakes - a significant upgrade, but not disks.

Your SM465 will bolt up to your 225 V6's bellhousing. You will then need to purchase an adapter kit (ca $500) to adapt to a transfer case. If you are converting to a centered axle, you may as well use a Dana 300 transfer case, which will give you a superior low range to the Dana 20 an intermediate would have.

Another - likely less expensive - option would be to use the transmission and transfer case from the axle donor. This would give you a T-14 or T-15 3-speed or a close-ratio T-18 4-speed, all which would have to be adapted to the V6. The engine adapter is less expensive than the transfer case adapter, however. Any of these would be suitable for the use you describe.

For both the dunes and mudding, I expect your biggest issue will be limited power from the V6, not drive train strength or lack of deep gears. If you want to get into the big rocks, the super-low gearing of the truck 4-speed will help. From your description, it sound like you may never use what the SM465 will provide. For exploring on two-tracks and light trails, you don't need anything beyond the factory equipment. These Jeeps are very capable in factory form - that's what they were built for.

You could just rebuild the T-86 with T-90 gears and just put it back together, and be ready for some serious wheeling. I suggest you wheel it for a year and then decide what you want to change. However, I would put some kind of traction device in the rear axle right away - personally I feel that a rear LSD is very helpful. The lunchbox lockers are fairly cheap and easy to install.

A 4" lift is a lot of lift, and rather pointless. I'd suggest a 2.5" lift like BDS sells. This will be fine with 33" tires. Here is my CJ-6 with a 2.5" lift and 33" BFGs -



I would not want any more height than that.

 

Great advice! I was reading on JP magazine's tire fit chart that 33s wouldn't clear the fenders without cutting unless you had a higher lift. I would rather have less lift.

On the LSD for the Dana 44. I didn't think they sold LSDs for the stock Dana 44 anymore unless you converted to higher splines?

 

Used. Look for a PowerLock for 19 (?) splines. Just check around.

 

Great advice! I was reading on JP magazine's tire fit chart that 33s wouldn't clear the fenders without cutting unless you had a higher lift. I would rather have less lift.

On the LSD for the Dana 44. I didn't think they sold LSDs for the stock Dana 44 anymore unless you converted to higher splines?

 

There should be a lot of 19 spline traction devises around for the rear axle. I would be looking in the classified as a lot of people swap to 30 spline and that si most of the market. The weak point will be the keyed hubs which are eliminated with a full float kit.

Front D27? I would be inclined to swap that for a D30. Maybe just my luck, but I've chewed up more of those than the D25's.

I agree with Tim that the SM465 is probably overkill for what you will be using the Jeep for but since you have it, I would spring for the tcase adapter and use it. Unlikely it would ever need any repairs. It will also make the 3.73 gears more livable with the 6.55:1 granny gear. For the lift, I don't agree with Tim. With 33's and a 2.5" lift, the rear tires will be into the rear wheel well cutouts unless you have pieces of 4x4 for springs. A 2.5" lift and a 1" body lift would likely clear. That said, a little sheet metal trimming there would allow a 2.5" lift to work and keep the center of gravity lower.

 

Also keep in mind to bolt the SM-465 to the Buick bellhousing the bellhousing and front bearing retainer of the transmission need machined.

 

If your current axles look fairly good inside it's going to be cheaper to just clean them, reseal them and use them.
You can always change parts around later if you break something or feel the need.

The long wheelbase CJ 6 is the ideal candidate to receive an "intermediate" drive train.
Standard "intermediate" CJ drivetrain includes the Borg Warner T15, the Silent type Dana 20, the D30 front axle and the centered D44 rear axle.

The T15 will likely be ideal for your needs.
The only drawback is the factory D20 low range ratio.
You can fix that problem with a 3.15 Teraflex gear set.
The D30's and flanged D44's are the optimum CJ axles.
The D20 does not accept a O.D. so you really need to run 3.73 FDR if you run it on hi-way.
The 3.73 FDR will not provide a low crawl ratio unless you install a low geared 4 speed.

 

I think the intermediate axles are a great recommendation as well as going with the SM465 and using the centered Dana 20. The 465 really helps make up for the 20's 2;1 low range. On my A1 I went with the Black Diamond 3" lift and with the 33 10.5 15's on it currently I have zero rubbing. An open knuckle front might get you into the springs, but no issues in the rear. I did rub with the 35 12.50 that I originally had on their FWIW.

 

Thanks for the great feedback. After reading the feedback, I think I'm going to open the diffs up and see what condition they are in. I might just use stock until there is a need to swap--it will get me on the road/dunes quicker.