Should i install the center diff?

[Nitrius]

So i just got my Slash 4x4 Ultimate, and am wondering if i should install the center diff or not. If i've understood it right it will allow the power to distribute equally to both front and rear tires, which to me sound very good. What do you think?

And if i install it, is there anything else that may be a good idea to change as well? Like the gearing or anything like that?

[madkawi650]

If you plan on running more than 2S lipos I hear the Diff can not take the extra power. I don't have one but have looked into getting one untill I read about not handling 3S, then I changed my mind. I do however feel that it would help with the pushing (understeer) in the corners that you get without a center diff.

[Nitrius]

Was only thinking to use S2 LiPo batteries, don't have any S3, at least not yet.

[madkawi650]

If you are looking into buying one,, Check out the all aluminum FLM center diff.. I hear it seals better and is way stronger.

FLM is Fast Lane Machine. check em out on the web.

[Nitrius]

I got the center diff that came with the ultimate edition, FLM is probably more durable but i rather use the one that came with the truck until it wears down or something. Question here is if it's worth installing it over the slipper clutch if your gonna run more on a track than doing hardcore bashing?

Not gonna be any serious racing, it's just that i have a track nearby that i like to drive on.

[Jakey]

The center diff works great and really helps to stabilize the truck during hard acceleration. It also reduces and in some cases eliminates wheelies under heavy throttle. Another benefit is better cornering. However yes, it leaks and it leaks a lot, which is very sad since it improves the handling so much. I fought the leaking then worked with the it; trying everything I could think of and finally gave up. I recently installed the FLM setup and it is not without problems, BUT it does not leak. :)

[Nitrius]

the Traxxas center diff leaks you say? In what way? The diff oil inside it leaks out or?

[Jakey]

Yes, the fluid leaks out fairly quickly. It leaks around the main shafts on each end and at times it will leak around the housing cap seal.

[El Sob]

Its funny, my bashing partner has the MMM setup in his truck. Runs two 3s batteries so that it is 6s all together and he runs the center diff. He he's had it for at least seven months and has had no problems at all with it.

[fastlane01]

I use the center diff. I think it handles much better IMO. As far as leaks haven't seen any yet except for my rear diff.

[Sierra 008]

I run the center diff on 3s, but I have the Kingshead motormount, metal gears and the FLM aluminum diff. Runs perfect and it is a world of difference when it comes to controlability during a race. I would seriously recommend upgrading to an all metal diff for this truck, ditch the plastic it will only cause problems.

[koolkat]

It is interesting the contrast between peoples experiences with individual parts. Many relate bearing seizing problems and others back axles bending and others have never had problems.

Now you say your mate has no problems running the CD on a very high power setup yet many have destroyed theirs on 3s.

Maybe it is bad quality control on the part of Traxxas or those that they pay to make the parts to have such a variation in performance of parts - or maybe some people just abuse the parts harder than others.

In response to your statement about power distribution - a slipper sends the same power to front and rear wheels as both spin at the same speed. A centre diff sends most power to the wheels with least grip.

While this sounds counter-intuitive and does in fact reduce your acceleration, it does greatly improve control as on acceleration it allows the front wheels to pull the car out of corners which stops the jumping around and fishtailing in normal hard acceleration as the back wheels slide around, and on braking into a corner it puts most of the power to the back wheels - allowing the front to grip better and hence reduce understeer - but does reduce braking capacity somewhat.

So to put it in a nutshell - the centre diff reduces acceleration/braking but greatly improves handling. On a tight course handling is the most important component of performance.

The centre diff greatly increases wheelspin by putting the power to the wheels that are slipping and hence will wear out your tyres much faster - particularly the front ones.

I think it is much more fun bashing and scrap racing with the slipper clutch because you get more raw acceleration and you have to tame your car rather than have the centre diff do it for you - and there is much less stress on the driveline, motor, and wheels because of the slipper action.

Try it with and without the CD. I went from the RTR to add sway bars and then tried the CD - less fun for bashing when they are both on but much better for racing. Both sway bars and CD make your car slower by moving power from the wheels that have the most weight on them, and hence the best grip - and hence both make it a bit slower.

[Jakey]

Several months ago when I opened the box on my brand new Platinum Slash, I quickly examined all the truck and new parts included. The center diff assembly was inside a sealed plastic bag which was partially filled with diff fluid from the diff assembly contained within. The center diff had leaked a considerable amount of fluid before it had ever been used. Not a good sign.

I am not complaining, but rather pointing out a fact. I never contacted Traxxas for a replacement and actually went on to use the center diff for several months of racing. It just became normal routine maintenance after every weekend of racing to remove the diff, check fluid levels and clean up the ensuing mess. In spite of this I still recommend installing the center diff for handling improvements.

[Nitrius]

Thanks for all the answer, and nice writeup @koolkat, thanks for that.

Anyway, there was no diff fluid in the plastic bag that contained my center diff, and i've just installed it.

Onto something else, i have one more question, the slipper clutch has a bearing on the rod that goes into the driveshaft, according to the owners manual and the manual that came with the center diff, it looks like this is not used with the center diff, so i just left it on the slipper clutch and installed the center diff without this bearing, is this bad? Should i use the bearing or?

[El Sob]

I have heard of people doing that. It does go onto the cd. The bearing failing is what causes a lot of problems. It gets hot and warps the housing on the cd. But I have heard of people not running. I would think you would want to run it. That is just my opinion.

[Nitrius]

So you have heard of people not using the bearing? But you recommend using it if i understood you correctly?

[FFS RACING]

Yeah definatly run the bearing. I missed this when I installed the CD and the truck ran really bad. there was lots of noise, a slight wobble in the shaft and it also led to alot of junk entering the rear housing and eventually built up right where the motor mount and diff sit. this led to binding and some damage to the drive shaft, CD, chassis ect. Also caused my temps to jump due to the inefficent setup. It was a bad day. I'd rather have to replace a bearing than everything else.
Also the diff greatly improves traction so if you want performance this is a good idea. But the slipper works well too and is more fun when bashing.

Have no leaks to report yet

[Nitrius]

Yea, noticed some weird noise as well when i turned on the truck without the bearing just now, so i took it apart again and installed the bearing, sounds much better now at least.

Thanks for all the help =)

[FFS RACING]

trust me its better to have the driveline turning true than to end up with unwanted damage. Also my bearings are all still good.

[john01374]

I drove my 4x4 one time with the stock slipper and didn't like the push. Installed the center diff filled with 100K fluid and have had no problems in almost 6 months of running. I run 2S and 3S on a 9L motor. The KV is slightly less than the VXL but so far no problems. Also haven't had any issues with leaking.