What length screws are you using to attach the gear to the modded ring gear? I am not too familiar with the thunder tigre cup. I am guessing that the screws will have to be an exact length so as to not protrude into the interior of the diff and catch on the output gear...

I also thought you were going to use an ofna spider diff, did that not work?

Im not sure of the screw length, as for i put them in, and cut them to length, then sanded then flush on the inside, as for the cup i used a Onfa hyper 7 diff cup assembly, and the modded ring gear is after the teeth have been removed, i think its gonna work, just got to redo the shafts is all....it's very strong and wasn't to hard to do....once i get all the dimensions for the shafts, I'll add them to the sketch and post them here as well...

That clears up a few questions. Can you assemble the input shaft and the center diff assy into the back section of the trans case and snap a pic from the side? Something like this:

http://i206.photobucket.com/albums/b...p/DSCF2517.jpg

Just want to see how well the gears line up. If your modded ring gear is below the level of the input gear, the idler will not contact it. I had issues with the savage cup and my adapter in that respect. I could reduce the thickness of the adapter and try again.

yup sure can, give me a few minutes....

here you go...
http://img.photobucket.com/albums/v4...s/dscf1479.jpg

linc, one suggestion you could use to lower the diff cup, is replace the 6X12 bearing on the cup side with a 8X12 bearing, then the end of the diff cup will fit nicely into the bearing, & you will gain a few MM doing this....

Looks promising... I just got an erevo center diff in the mail (thanks jayjay283!!!), and may have to see if my machinist can mess with the gears.

Are you still using the oring gasket with the modded ring gear? I have a feeling that will help, as the diff gasket I am using causes some issues with overall length.

I would still like to have a custom made part that would be completely bearing supported, as yours is still rifing on the output shaft on one end...

Still the small 8x12 bearings required to have it supported are problematic...

No real way to get around the bearing issue, a bandaid fix at best.

I would almost like to try your setup, and remove the bearing carrier area of the diff cup. That way the original bearings could be used, and I could see the wear on the output shafts from the diff load directly on them.

May have to try that out, I have a spare ofna cup and ring gear. Back to them machinist!!!

Any idea if traxxas will sell the gear seperately?

I did that, actually opened up the hole in the trans case so that the extra length of the bearing carrier on the diff cup can sit thru the 8x12 bearing and go outside the case a bit, you can see it in this pic:

http://i206.photobucket.com/albums/b...p/DSCF2523.jpg

yup, very true, im now waiting for a new lower shaft, so i can turn it down and cut it to the new lengths that are needed, so maybe mid next week for me.....fortunate for me, my machinist does it on his lunch break, so no cost for me at that part, and I have access to a lathe and I can turn down the center of the shaft to the correct size needed and take measurements from there.... both designs look good.....keep up the work

I am in the process of buying a small lathe for doing stuff like this... I may try drilling and taping the gear I have... Might work. I also had the lower shaft turned down to be 6mm od along the length. I still have to cut it and drill the pin hole too. Fun stuff.

what the bolt circle diameter for the diff cup? and i see you got your traxxas gear still waiting for mine so can i get measurement for that too? waiting for parts sucks i got nothing to measure right now. what are the angles for the traxxas gear?

here is the drawing for the bolt pattern to drill & tap the 3mm holes in the ofna ring gear, after i finish my shafts, I'll get those dimensions and add them to the drawing as well....FYI, scroll down a bit, pic is at the bottom......sorry dang scanner placed it there...lol
http://img.photobucket.com/albums/v4...oltpattern.jpg

I have the shaft lengths, if anyone is interested.....just let me know, so tonight I will hopefully be able to test it, but I think it will not have any issues at all......
http://img.photobucket.com/albums/v4...s/DSCF1510.jpg

Well, everyone I was able to get a complete set of batts ran thru it last night, hopefully i can ge ta few more runs in today...if it stops raining that is, after i get a few more in, I'll pull it out and check it for leaks and wear ect....but so far it's working good and no wheelies, which is nice.....Im running 30k in the center....

How much are you planning to sell them for? When are they going to be available? You can pm me the price.