Two issues- front and rear ends

Hey guys n gals. I've got a 2000 Dakota 4.7L auto 4x4 CC SLT with two separate issues, one pressing, one not so much.

First: the rear end. It's started leaking fluid, and not just from one, but from two places. First is the obvious one, it's coming from around the rubber plug in the rear differential. I also seem to have a leak from somewhere around the wheel assembly as the back (center) side of the brake housing is damp on the driver's side. What am I looking at, and what is it going to take/cost me to repair?

Second: the front differential. Sometime before it came into my possession, somebody managed to almost entirely strip the output shaft of the driver's side of the differential, which fits into the driveshaft (not sure if that is the correct terminology) on that side which runs to the wheel. Not even trying to offroad, I managed to 'stuck' the truck one day, and in the process of trying to rock it out (one of two or three times I've had the occasion to use 4x4), I have apparently finished stripping the teeth on that shaft. Would I be better off dropping and replacing the entire unit (differential) or getting it repaired?

Thanks all!

The rear axle leak is pretty easy to repair. The axle shaft has an oil seal at the end of the axle tube. One must remove the rear wheel and brake drum. Then, one removes the axle shaft by unbolting an axle retainer plate (located behind the axle shaft) and then pulling the axle free. The seal should be an inch or two down the tube. Sometimes a special tool is required to remove it. Usually a large, deep socket can be used to install a new seal.

Installing the axle shaft can be a bit tricky. As you push the axle shaft in, you have to be careful not to allow the weight to rest too much on the new seal, or else it will be damaged and will leak. Also, one must be sure to align and rotate the axle when its nearly all the way in to make sure the axle splines get seated in the differential carrier properly.

You should get a service manual, if you do this yourself, to make sure the torque specs are right. Imo a professional mechanic shoudl charge about 1 hour plus parts to do this job. It's not difficult.

Check the brake shoes too. If they are soaked in axle lube, they need to be replaced. The lube soaks into the shoe material and cannot be washed off.

As for the front... call around some wrecking yards and see what the prices are for a used front diff. Make sure to specify the same gear ratio as the original unit. Be sure to get a new or good used drive axle.

Imo these units should be pretty cheap, since front diffs rarely get used hard enough to wear out, so demand should be pretty low.

Thanks for the reply! Now if only I could find somebody to buy it once it's all fixed, lol.