EB4 S3 diffs leaking....??

[Lessen]

any of you guys having this issue?

My S3 has been benched for most of the summer but I've finally found some time to fix the broken stuff this weekend. First thing I wanted to do was clean it up pretty good before I started disassembly. This is when I got the first clue. There were oil markings (discoloration.. if that helps the discription) on the underside of the chassis around the screws that hold both the front and rear bulks to the chassis. When I removed the front bulkhead there was quite a bit of oil on the chassis underneath it. Upon opening up the diff I was very surprised to find an extremely low level of oil (not even up to the bottom of the cross pins) and even that was extremely dirty. It was so bad it almost looked like black grease except not as thick and tacky. I've since completely disassembled and cleaned the differential but I didn't noticed anything wrong with any of the components. The inner outdrive o-rings looked perfect. The outer outdrive o-rings looked fine but they are so small I don't really remember what they looked like originally installed. I think they might be the cause but I'm not reall sure. I havn't taken apart the rear diff yet. I hadn't planned on it but I definately will now considering what I've found. I havn't checked the center diff yet either but I already had plans on changing oil there as well.

[Revo Rancher]

Mine leak. They also never really got a good break in, for some reason. They sounds like old semi-truck gears. I have them shimmed just about prefect but for some reason, maybe it is the metallurgy of the gears, they seem to leak and the oil is getting dark.

[vbgagnon]

A few things to do to fix the leaking...Use grease around the O-rings. Grease on the output shafts and I use 1000 wt on the cap or whatever you use to close up the diff. This way it creates a seal and won't leak. That was the thing I didn't like about the hyper, they used big thin o-rings, so I would just use some RTV sealant to keep the grease in.

[Thunder_Tiger_EB4_S2_Pro]

Hmm...not dis similar to the S2 i had. Leaky diffs are a pain in the A$$ to say the least.
The way i cured it, was to put blue hylomar gasket sealer on the o-rings and diff gasket. I also made use of some modelling plasti-card (another hobby of mine,.... model building) and made an extra tight fitting outer seal with the plasticard, a bike innertube repair patch and some inginuity, BYE BYE LEAKY DIFFS !!! Of course, it would help if i was using heavy diff oil, but i was running 80wt pure silicone oil as a friend recomended to "Tune" the diffs, so after a day or so, it got quite messy. Still, the mods i made worked out and stopped the leaks, so it is at least something to be thinking about.

How does the S3 run ?? any better than the S2 ? reason for asking is im looking at upgrading to an S3 after a year of running an S2 (i get it next week to replace the one that was stolen). Just looking for performance comparisons. The only thing ive heard so far is that they run about the same but that the s3 has better suspension setup.

[Mondo]

The TTR RTRs (EB4-S3 excluded, of course, being a kit) alway require a good allen wrench and screwdriver session
I found that most of the critical nuts, bolts and allen caps were far from tight.. This also included the front and rear diff screws! Years of competitive off road (enduro) bking has taught me to tear down and re-tighten anything that is to be ridden (or driven in the case of RC) off road..

Enjoy the S3, it's more than just suspension, it has an improved chassis, center diff with front and rear braking, improved oil shocks and suspension arms.

[Lessen]

thanks for the tips guys!

[Thunder_Tiger_EB4_S2_Pro]

lessen, did you manage to stop the diffs leaking on your S3 yet?

[Lessen]

I've only got around to rebuilding the front. Mostly because I also upgraded the shock tower and one of the toe blocks. I still want to do the other two as well but just havn't got around to it yet. I don't work on my r/c's near as much as I did a year ago or so. Just got to prioritize these days.

But, as far as fixing the issue I didn't do anything different to the front one when I rebuilt it. I do plan on using the suggested methods above on at least the rear to see how much better it will work. Eventually that is.