2014 E350 4matic in shop with front driveshaft failure
 

Brought one in on the hook with the front universal on the front driveshaft that catastrophically failed at around 160k miles. I'm now in the process of replacing the front driveshaft on it.

In looking closely at the transfer case gearset with the output shaft going to the front driveshaft it seems to be a very poor design in the fact that you have to replace the entire gearset to replace the universal:eek:. Looking on ebay it is about a $1100 part used.

What a POS design.

By front universal you mean in between the front diff and xfer case?

The front CVs/axles are a pretty common failure poibt but dont think ive seen a shaft failure.

Front universal (only universal joint) on the d/s that goes to front diff.

The poor design is the way the universal joint for the splined shaft that slides into the rear of the front driveshaft, that goes to the front diff, does not look like it can be easily replaced.

Ridiculous design in my opinion.

I've replaced about 4 of these the last 5 years

I learned that you have to be really careful with the seal on the output to the front diff gearset.

Funny coming back to this thread. My other "fun" car is a heavily modded saturn sky, pushing somewhere around 380-390 lb-ft of torque.

In a shocking twist (ha!) that torque sheared the bolts at the diff mounts. The relevant part...I learned that the driveshaft has an actual CV joint at the tailshaft of the transmission and a guibo on the other end like our mercs. Thats something I havent seen before, and apparently extremely sensitive to mm-level misalignment.

Learning very quickly that theres quite a few interesting variations to driveshafts that I had no idea about. Anyways carry on - good luck with the front diff work!

Got new seal in and everything buttoned up. Job went well. A couple of comments I'll make are:

A) Get someone to hold front driveshaft gearset in place when starting fasteners for intermediate cover. Makes job a lot easier. The lovely Ms engatwork helped me:).

B) on the 2015 E350 chassis you can remove front d/s without breaking transfer case down. The youtube video I watched was in error in this regard.

Every 4matic with transfer case (differential) built into rear of the transmission like these will eventually have to deal with this d/s system.

Well heck, buttoned everything up and I've still got a leaking seal around the transfer case output shaft going to the front end. I am getting faster at replacing.

Aw man thats the worst feeling -- sorry to hear

Third time is the charm. Replaced seal again yesterday and finished putting everything together this morning. I put a little grease on lip seal prior to install and there are now no more leaks:).

LOL. There are two different type transfer case, one is built onto the back of the tranny and shares fluid with the tranny. The other bolted to back of tranny but has its own fluid, separate from the tranny.

The bad thing about the design that shares fluid is that you can't replace the universal in the gearset that sends power to front driveshaft. Used gearset for this type transfer case are available on ebay for around $1100. This transfer case does have a "differential" assembly built into the main gear assembly that bolts to output shaft of tranny.

The biggest issue I've seen on the other type transfer case is the chain wears and has to be replaced. Im thinking this unit is the one the 4wd Sprinters run.