# Cat Rear Diff Experts???? (beefed up diff cover)



## Rubberdown

As some of you know, there is currently no one making the heavy duty rear diff covers for the Cats......BUT.....we are working on it. I do have a few questions though, and getting customer and rider feedback has helped us over the years to make better products, we listen to our customers. So here I go, looking for input on this project.Below are 3 pictures of a diff cover off an 08 700MP. In the last picture, there are 2 circles, one red and one yellow. This part in the red circle seems to just be a left hand threaded torx head bolt of some sort with a shim or washer underneath it. Its not magnetic (to catch shavings like most drain plugs) but it is steel, and its left handed....what the HELL is it and what purpose does it serve? In the parts diagrams, this thing is in almost every single cat rear diff from around 2003 to present day. In the yellow circle, it looks like a pocket for another one of these torx headed bolts but I wasnt really sure if there are even threads in that hole, I didnt look close enough at it.Now, aside from wanting to know what these to circled items or areas are for, do they NEED to be in the diff cover, like, do that have a functional purpose in how the diff operates?Next question, this cover doesnt really feel like a thin cover, maybe this is one of the better ones, I read that there were some thinner ones and some thicker ones, this must be one of the thicker models, what do you guys think?Lastly, I was thinking about beefing it up by adding thickness to both sides of the cover, maybe a 1/16" added to the outside wall and a 1/16" added to the inside wall between the webs inside the cover. Also, I figure what the heck, lets make the webs wider too, lots wider, and the material around the large inside diameter, make that wider and the material around the center inside diameter, make that wider, so the pie shaped recessed sections would be smaller, know what I mean?Any ways, we hope to start drawing it right after the Christmas holidays and with any luck, cut our first 6 prototypes mid January. So ANY advice or input from you Cat experts is welcomed with open arms so we can try and provide you with the best product exactly how YOU GUYS want it.


----------



## gpinjason

I know nothing about Cats... but looking at it, and looking at the parts drawing... this is my assumption...

The part is called a Thrust Button, and it has a shim/shims under it.. Since it is called a "THRUST" button, I'm assuming it maintains some kind of "load", and the shims mean that it needs to be set correctly... 

Looking at the drawing, and the location of the button, it's behind the ring gear, right where the pinion gear makes contact... so my guess would be that it's some sort of "back-up" for the ring gear, to keep it from deflecting away from the pinion under load...

And again, this is just an "assumption" but it sounds like a good one to me... LOL :thinking:

Parts # 6 and 7 in the drawing below...


----------



## Rubberdown

Ya, I found the parts on the same drawing, but this thing shows no wear or scratches on it, it has never been in contact with the ring gear at all....hmmmm....not really sure at all here? Basically, if it doesnt need to be in there, the diff covers will cost a bit less to make them and therefore a bit less on the retail end of things for the guys looking at buying one.


----------



## Swamp Star

I havent had to tear into the rear end of mine but to my knowledge its just like the front for the most part(VERY VERY simple). If yall do get a billet side cover worked up let me know. I would be happy to do some test dumming for yall.


----------



## Savageman69

Ill be buying these from you also paul


----------



## Rubberdown

Okay, the first run of covers will be made this week, as long as nothing puts a hold up on the machine time, I "should" have some ready by Wednesday, with any delays, mybe by Friday. We have enough material for a few pieces but I think I know where I can grab some more to try and get at least 10 covers made.

We came up with a couple changes we are going to do to OUR cover to make it work better.....okay, maybe not work better, but help keep the gear lubricated better inside the diff....so I guess that IS better LOL.

I saw some talk on another forum where a few people are concerned that my price will be higher if we get them anodized with what they call a HARD BLACK anodizing, and have them engraved. Let me reassure you all, I aLREADY have a retail price in mind, it has been the same price since I thought about making these covers because I am pretty sure I know "roughly" what it will cost me to build them. Adding the anodizing and engraving was thought up just recently and will not affect the final product price. I do some work for a company that makes motocross covers and they send out covers for Hard Black all the time, my parts would just get piggy backed onto their run of parts and therefore the anodizing cost would be $5 or less per part (my best guess). the engraving will likely not be a machined engraving, but a laser engraving, this will make the engraving almost look like a silvery white finish on the black part and looks really nice. This process is done where I have my full time day job and I would personally be doing the engraving, this will not raise the price whatsoever. Here is a part we custom engraved for a customer, it is anodized in hard black.











I will start a new thread with pics as soon as I have them ready!


----------

