chevy264

Evening everyone, looking for some sound advice; my front differential has failed on my Earthquake 3.0 this past weekend. Isuspected something was going wrong, during hard braking I could hear a 'ratcheting' noise loud and clear coming from the EQ 3.0. I am automotive trained and Iknow that 70% plus of a cars braking is done by the front brakes. Looking at the EQ, the brunt of the stopping force is brought thru the front diff I am guessing that thru normal use this is a common failure? With the front differential out of service, and in a hard braking application, Iam now hearing the ratchet noise, assuming its coming for the rear diff?

I can rebuild the front differential, I'm sure Ihave the skill to, with the proper replacement parts.

But what can Ido to improve and/or prevent another failure? I would like to continue to get the most performance from my EQ 3.0, but Idont want to look forward to down time and repairs.

Thank you in advance for your comments.

rchobbyunlimited

Yes the diffs do wear out even faster when you do alot of fast take offs, huge jumping, and hevy braking. Make sure that when you rebuild the diffs that you fill the diffs up with a good diff oil. When i have to rebuild 1 diff i like to change and rebuild all 3 of my diffs at the same time i just figure that if one goes out that the other 2 might be close behind, and at the end of the race seasons i rebuild all 3 diffs any way and I have found this has great reduced me have any diffs going out. I have noticed that with redcat I have removed several diffs and there was not any oil in them at all and this is a very quick way to burn a diff out so when ever i get a new redcat one of the first things I do is take the diff apart, and if there is ant oil in there I will pour it out clen the parts and replace with a good quialty diff because if there is any oil in the diif its always a cheap thin looks like salad dressing oil in the diff and thats not good. Also I always like to change the washer ring in the diff also to ensure that the oils does stay in the diff i have found they were out pretty quickly. Hope this helps.

rchobbyunlimited

Also on another thread they posted this article http://www.rc411.com/pages/howto.php?howto=35&page=1 on diff shimming I have not used it yet but it does makes great sense to take any of the wiggle (play) out of the diffs.

chevy264

Took the front diff apart, and found that the pinion is totally cleared of all teeth.
Also noted that it is a totally "dry" assembly? No lubricate used in the differential's?

chevy264

I have conflicting information on what the correct part number is for the diff gear set. My parts catalog included with the Earthquake 3.0 calls out for a; BS903-105.

However the online catalog at the Redcat web site calls for; BS803-027.

Anyone advise me, before Iorder?

rchobbyunlimited

I personally would go with the online catalog number because sometimes redcat changes there part number so the online would be the most accurate. Also you can give them a call and they would be glad to clear it up for you. But I would go with the BS803-027

rchobbyunlimited

Yes i have seen that several times so when you get the new prat make sure you get some good diif oil to put in. Also while the car is down I would take the other diffs apart and clean them real good and put in some good diff oil they probaly are dry also, and this will prevent them from going out on down the road.

chevy264

Should oil be used or should the diff housing get packed with a grease? I have a high temp and pressure grease with 5% moly, that is used for lawn mower deck spindles. It is engineered for extreme operating conditions, I am thinking about trying it.

rchobbyunlimited

No siclone oil should be used inside the diff grease should be used on the outside of the diff on the teeth. Grease is not good at all inside the diff.

sdnitro

I have replaced both the diffs in my earthquake 3.5 several times and cannot make them last.  The rear diff just went out driving on sand and

less than a tank run time, and I installed the complete unit rather that installing the ring gear and pinion like I have in the past. I believe the

replacement parts are falty, but I must be the only one with this problem so far.

rchobbyunlimited

Try using a thicker diff oil in the diff the next time you chage them out and see if that helps any. Also check to make sure that there is no play (wiggle room) on the diff when its installed with the dog bones in.