If you're new to Jeeps, you've probably heard how everyone scorns the Dana 35 but why? Well, this time I'll discuss a bit of history of the 35, how to identify them. I'll also point out their weaknesses and what can be done about it.
HistoryThe Dana 35 was first seen on the 1984 Cherokee, Comanche, Wagoneer. Later, it was used on the Wrangler, Grand Cherokee and Liberty. The Dana 35 has a 7.562 inch ring gear. The pinion gear is 1.406" in diameter and has a 26 spline shaft. The housing is around 2.64 inches in diameter and the axle shafts are 1.13 inches in diameter. The true name for the axle is the Dana 35C. The C stands for Custom. This is because the axle housings were sent to Jeep unfinished. Early Dana 35's from 1984 to 1990 used pressed on bearings. This means the axle shafts are retained by the bearing. Later, Chrysler wanted to speed up the process and changed the design to use a C-clip. The C-clip is used to lock the axle shaft into the housing through the side gears in the carrier. WTF, does that mean? The axle shafts are slid into the housing. The spline area passes through the carrier and through the side gear. The C-clip is slipped onto the end of the axle shaft. The C-clip prevents the axle shaft from backing out since the gear is held in place by the carrier. The axle shaft is then pulled back and the C-clip is pulled into a groove which prevents it from falling out.
There are some other differences that are easier to spot. The easiest might be the brakes. Early models use a 10 inch by 1.75 inch drum brake. The drum was vented or ribbed to help get rid of excess heat. Post-'90 D35's use a 9 inch by 2.5 inch drum that is smooth. The 9 inch drums are more common and better over all.
There was another change in the early 90's. Around 1992 to 1993, Chrysler decided to change some more things. In the '90's, ABS was being used more and more. It was never really used on Wranglers but it was becoming standard on the Cherokee's and Comanche's. To simplify the product line Chrysler converted all Dana 35's to ABS versions. What's the difference? Overall, not much. The axle shafts have an area milled to accept a tone ring. Internally, there was one big change. The side gears on the non-ABS versions have a larger shoulder diameter. Ok, lets make it simple. Think of the side gear as a mushroom. The gear part is the head. The shoulder area is the stem. The stem is around 0.25 of an inch larger in diameter. So, what's the big deal? Well, if you use a drop-in locker like the Lock-Right, EZ-Locker, etc. you will need to pay attention to which carrier you have.
All versions of the Dana 35C have shims that are put on after the bearings are pressed onto the carrier. Why is this important? If you do your own gears, it will make things a lot easier. You won't have to remove the bearings every time you need to reset the shims when setting up gears. It's a good thing to have. There is a catch though. The Dana 35C also uses a crush sleeve to set the pinion bearing pre-load. This is how much pressure on placed on the pinion bearings once the pinion depth is set. What is the pinion depth? The pinion slides into the housing from the inside. Its depth is set by adding or subtracting shims behind the gear. This is used to set the correct gear mesh for the gears. Also, all stock Dana 35C axle shafts are 27 spline.
The overall shape of the Dana 35c housing is an oval and uses 10 bolts for the cover. Early models used a threaded oil fill plug. Later models use a rubber plug. On he housing, near the 2 o'clock position of the cover is a stamping. Cast into the housing, it should read 35C.
The Bad
So what makes them so bad? As I discussed earlier the axle shaft is 1.13 inches in diameter. This is rather skinny near the spline and is prone to breakage. This is the number 1 problem with the axle. If you happen to own an early model, you'll be able to limp to the side of the road or back to base camp. If you own a later model, you better hope you're not driving fast and you better stop quickly. On later models, once the axle shaft breaks, the shaft, brake drum, wheel and tire will walk its way out of the housing. This will usually take out the rear brakes and leave you running on three tires. The axle shaft typically breaks because the tortion limit of the axle is exceeded and the shaft is twisted apart.
Remember those crush sleeves? Crush sleeves can get damaged by impact to the pinion yoke or driveshaft which can result in damaged gears. Then there is the housing. The axle tubes are rather small. While wheeling the axle housing can actually flex enough to cause the shafts to bind with the side gears. If there is a locker, the internals of the longer can be damaged. This was a problem with ARB's early on.
Then you have the gear size and selection. The Dana 35C has a 7.562 inch ring gear. This is pretty small for a ring gear. (For comparison, the Dana 30 has a 6.5 inch ring gear while a Dana 44 has a 8.5 inch ring gear.) Why is this bad? When gears are made to numerically higher ratios, the overall diameter of the gear can not be changed. This means the gear teeth have to be smaller. If the teeth are too small, they may not hold up and shear off. (This is also a problem for the pinion gear.) Because of this, the lowest gears available are 4.88:1 ratio.
The GoodYou're in luck there are ways to strengthen the Dana 35C. Aftermarket companies like Superior and Warn make things to help get more out of your axle, for a price. The first are heavy duty axle shafts. These come from many different companies. They range from 15 to 18 percent increase in axle shaft strength. These are direct replacement axle shafts so major work is required. Superior was the first to come out with what they call their 'Super 35' kit. This replaces the stock 27 spline shafts with 30 spline shafts. What they do is remove the taper from the stock shaft and make the axle a uniform 1.30 inch diameter shaft. (The Dana 44 uses 30 spline 1.30 inch axle shafts.) This requires a new carrier which usually means the carrier will be replaced with a locker of some type.
Warn decided to take a different route. Instead of increasing the axle shaft size, they relieved stress from the axle shaft themselves with a Full-Floater Axle kit. What this means is, in a stock setup, the axle shaft bears all the weight from the vehicle. This is referred to as a Semi-Floater. A Full Floater system shifts the went from the axle shaft to the housing. This is done with a hollow spindle. The wheels are attached to the spindle so the axle bears the weight. The axle shafts then 'float' inside the housing. Splined hubs are used to turn the wheels. Warn sells one kit that keeps the stock bolt-pattern and uses Explorer-style manual locking hubs. The other kit changes the bolt pattern from 5 bolts on 4.5 inch pattern to 5 bolts on a 5.5 inch pattern. This requires new wheels but allows the use of more common hubs or drive flanges.
It should be noted that Superior is also making Full-floating axle conversions which started this year.
Superior also makes a truss for the Dana 35C. The truss has an integrated differential cover which makes for more involved oil changes but strengthens the housing quite a bit. Trussing the housing is nothing new. The premise is to add supports to the housing to make it more rigid. This can be done by welding or bolting a support structure to the housing.
A simple upgrade that is not really a part of the differential has to do with the driveshaft yoke. The Dana 35C comes with metal straps that hold the U-joint in place. It is very common for people to over or under torque these bolts. In either case, the bolts will fall out or shear off living you without rear wheel drive. There are kits available that allow you to change the strap design out for a U-bolt design. These are stronger and there is less of a chance for them to break. It's a cheap way to make sure you're not left stranded.
The UglyNone of the aftermarket parts are cheap. When it's all said and done, you will still have a Dana 35C, abet an expensive one. Make sure you plan out your attack before hand. In many cases, it's cheaper to upgrade the whole axle to something stronger rather then throw money at the stock axle. The Ford 8.8", Dana 44, Toyota 8", Dana 60, Ford 9", Corporate 14-Bolt are just a few of the many axles available. Some are easier to swap in then others. Some are expensive, too.
