JQuest64

Just blew the rear diff in my FS yesterday.
Upon taking the thing apart I realized that this is one hell of a poorly designed diff.
The shafts that the planetary gears ride on inside the diff are held in the diff by the bearings. What the hell??
Apparently one of two things happened, the bearing failed and allowed the shaft to slip out, or the shaft snapped and worked its way into the bearing.
Has anyone with and MCD or FS had a problem with their diffs yet, if so what have you done to remedy this? I can see this problem recurring over and over again.

wan6176

post pic bro

bentley marshall

hey have ya got any photos of your diff ??? and did you take your diffs apart and chec and regrease tham ?? i found one of my diffs had very little grease in it and was binding i had to file down the ends of the gears to get them to run free

JQuest64

Here are some pics I snapped quick. As you can see, there is nothing that holds the shafts in place other than the bearings.

JQuest64

I did bentley. I tore them down and repacked them. They ran very smoothly and I actually thought they would hold up quite well.

bentley marshall

Ok thats a bugger what fs do you have ?? maybe the pins are to soft ??

JQuest64

I have the MT. It does seems as if the pins are too weak possibly. I may order and MCD diff to see if it fits and if it is any stronger.

PowerSlideRacing

MCD diffs the pins wont move. Better yet get the MCD LSD diff.

Foxy

I was looking at these the other day (MCD LSDs), they look awesome. If they are a direct fit (I guess they should be), although they are expensive, they would be well worth it, and are still cheaper than a lot of other aftermarket diffs.

vertigo performance

MCD diffs don't have bearings on the smaller shafts.
I don't see bearings on yours either

JQuest64

Bearings were taken off but they ride on the outer shafts you see in the picture.
MCD diffs must have a bearing in the same spot, what else does the shaft possibly ride on?

vertigo performance

I get it now..

Chances are the shaft was poorly made and snapped. The MCD shafts seem fine, this design has been around for years.

JQuest64

The design might have been around for quite a while, but MCD diffs are just as vulnerable to the same failure.
pwaicon's MCD had the same failure occur to his Baja 1000

http://www.rcuniverse.com/forum/m_7222513/tm.htm

vertigo performance

Maybe hardened pins are the answer then. I wished these companies would stop cheaping out and make proper gears instead of planetary gears

SilverSteel

There were some problems with the standard diffs from MCD, but if you had problems you got them replaced!!!!!! for free of course! MCD now has some redesigned stronger standard diffs, they actually care for their customers. If you want to have some "bulletproof" diffs buy the LSD Diffs from MCD, when they fit?

If you buy some cheap clone and now complaining about some poorly copied diffs.......... you get what you pay for.

Greetings SilverSteel

JQuest64

Stolen or not, clone or not, it is a poor design that you actually paid more for in your MCD.
Apparently these diffs were still shipping with Baja 1000's, so MCD has not been burning the midnight oil improving them.

You anti clone clowns crack me up. People shelled out $1,500 for their MCD's and got the very same diffs I got in my $800 clone, problems and all.

TBQH, I could buy 2 LSD's for the front and the rear of my "cheap" clone and still have paid less than what you paid for a roller without those same LSD's.

SilverSteel

You see that is the difference you HAVE to buy new diffs, me not i got them replaced for free. As a MCD owner I get support from the MCD dealership here if I have a problem.

If you don't want to spend so much money on the LSD diffs then I can recommend the 2008 Diffs from MCD. It's the same design like your old ones but the pins that holding the gears are now thicker and better hardened. Also the planetary gears have one teeth less.

I don't know your diff but are you sure that the pins came out of the case into the bearing? The MCD diffs have a tight fit so it is not possible that the pins come from inside out.

It is OK that you have bought a clone, but don't complain about the company that invented this car. You have to complain only about FS that they didn't recognize the weak part in the MCD car and sold you a better solution.
BTW while FS still sells the same car, MCD made major improvements.

The second EVO II series and all EVO III cars from MCD have the new 2008 diffs in it, if you get an old car blame your dealer and try to change to the new version.

Greetings

Isle of Wight Basher

Indeed MCD made improvements (2 new models in under 6 months !!!) with the evo models, however they showed no regard for existing customers, ie major design changes and no conversion kits, plus due to the nature of the changes many of the spares I had built up would have been redundant.

That is why I sold my MCD and would never buy another car from them. It's a shame as I loved driving 4wd.

Also I know of at least one dealer in the UK that held back the EVOIII models until they had cleared their stock of "older" MCD models, all too cynical for me I'm afraid.

SilverSteel

Until now there is no conversion kit for ProLine models to EVO III that is right but my dealer tries to get one together with a good price advantage. But there is a conversion kit from EVO II to EVO III models, at least here in Germany available at mogatech.de. There is also a conversion kit from ProLine to EVO II available at mogatech.de but I think that is not an official MCD conversion kit.

vertigo performance

Something to think about.

When any car company (fullsize or RC) make major changes it is called progression. If companies were held to making new models compatible with old models there wouldn't be any new models or technology.

Isle of Wight Basher

Indeed, But my original Race runner was 2 models out of date in under 8 months, and I felt that no consideration was given to existing owners.

After all they were fixing weak points of an existing model, not major design changes or a new model, and it made upgrading my 8 month old (well over 1200GBP) car out of reasonable financial consideration. I know of at least one owner who upgraded (at the cost of hundreds of pounds) to evoII only the have the evoIII follow within a couple of months. not a happy bunny.

Foxy

Its a very good point. These cars (ESPECIALLY the MCDs) are not cheap. Look at Losi and Associated, issuing completely free upgrade packs to solve initial problems for early adopters.

It's not exactly expected for companies to give away large amounts of free stuff, but those who have gone through the above scenario, certainly have a right to feel hard done by.

SilverSteel

Got the info today that the conversion kit from ProLine to EVO III will cost about 325€, if you buy the parts separate it will cost over 375€. Price is without EVO rims, with EVO rims 375€ with EVO rims and tires 425€.

I think it is acceptable.

If you think of the ProLine it is not a bad car at all, there are no major problems besides the diff (but I got them replaced) so you can do everything what you could do with an EVO III model. Have Fun with it!

And I think it is a nice gesture to offer a conversion kit for the ProLine series with some rebate.

Isle of Wight Basher

I'm sorry, but I dont. To convert and replace the spares and different wheel/tyre combos's I had built up would have cost the price of a new car.

Don't get me wrong, I loved my MCD, but couldn't justify the expense to solve what was a design flaw, or rather a lack of R&D, the official word was that the changes were to correct the steering geomatry(sp), but it wasn't, it was to get over the fact that offset wheels on an open wheeled car were vunerable.

splcrazy

Pffft LOL that looks like the sort of diff internals you find in cheap nitro models , i really like the idea of getting a FS king kong but when im ready im getting a FG monster truck , im going fg all the way.