changing a leaking differential pinion seal

after a lot of searching I've not run across many threads from people who have changed there own NCV3 differential pinion seals but plenty who have tackled the job on their T1N's.

Has anyone performed this replacement on their 2007+ Sprinter? How hard was it and how many miles since the repair?

I wish someone would say the repair is simple, such as mark the position of the yoke to shaft, count number of turns when removing the nut and reinstall in the same manner (to achieve same bearing pressure that was present before the removal).

This video makes you want to be cautious; https://www.youtube.com/watch?v=ofiLUo0aWqM

Makes me wonder how many times we would take it to the shop and have the dealer put the van back together with the new seal and have the drag torque measurement off and sell a new differential/rear end?

If you have time to look through the other videos found on that youtube channel, there are some that relate to Sprinters.

Its rare the seal fails or begins to fail without reason. The older 190E saloons, R129 SL had some common leakage at the pinion seal, almost by design, A better quality seal cured it, but the labour cost of doing the job properly often outweighed the advantages of drying up a slightly damp diff nose.

The Sprinters, Crafters and Transits that have this leak usually have some nose bearing and pinion wear to boot - Pinion bearing wear will cause opening of the seal as the spinning diameter of the worn bearing damages the seal lips, as does out of spec pinion pre-load as the output shaft starts to move backward and forward slightly (load and overrun) - again taking its toll on the seal. So often there is other mechanical things to deal with once you get in there and start to investigate why the leak.

Simply dropping the prop shaft off the diff with the vans wheels still on, atop a four post ramp, and 'air-gunning' off the pinion nut, replacing the seal and running it up again is most certainly destined for disaster. There is a procedure to follow, a deformable washer to set on some cases and torque/drag measurement and adjustment to the correct amount that determines pre-load of the correct amount. I have in the past considered pinion bearing replacement jobs and by costing the parts and time-taken to do it by the book (no point otherwise) its always, always uneconomical to that of simply fitting a used dry, unworn example.

If you have plenty of time on your hands, the correct tools and some engineering ability, go-for it! Though from a commercial point of view of keeping a not-so-new-van rolling, its not a procedure of choice. You need to be pretty sure of the reasons the seal is is weeping, is it just a seal fail or more sinister ? - If you don't do your homework properly and the job 'grows', worse still you hit or find an internal issue as you go - you would probably end up fitting the used unit that you could have been better off exchanging complete in the first place. My my 2c....

All the best

If you decide to exchange the axle wholesale - see below for some info:

http://www.mercedes.gen.in/sprinter-differential-noise-axle-replacement/
http://www.mercedes.gen.in/later-sprinter-crafter-axle-swap-tips-notes/

Steve

When this has come prior..........MB has a weep vs. seep vs leak policy and weeps and seeps are considered normal. The fact the front of the diff is wet or damp is not considered to be problem at least as it pertains to the policy.

showkey said:

When this has come prior..........MB has a weep vs. seep vs leak policy and weeps and seeps are considered normal. The fact the front of the diff is wet or damp is not considered to be problem at least as it pertains to the policy.

Click to expand...

Weeping pinion seals are pretty common and as long as the leak is only of the nature of a slight film on the front of the differential (no puddles, etc.) then in my experience it's wiser to just leave them alone as any fluid loss will be virtually nil between changes. IOW one of those situations where the repair has a greater chance of causing a subsequent problem than the original issue did.

.

good thoughts guys, thanks.

the only reason I put this on the maintenance list is because sometimes after making the hour drive to work I occasionally get a whiff of a gear oil smell from behind the van.

I'll check the fluid level at this point and address the problem if it gets worse.

If you search around on this forum it appears that pinion seal leaks are fairly common. Mine was leaking to the point that it was leaving leak spots on my driveway.



Just had the seal replaced along with the 80,000 mile service by local Freightliner Sprinter shop in Annapolis. Seal is only about $25, but it is 3 hours of labor to change it. I've attached a copy of procedure from WIS.