RB7 gear diff build
 

I watched the video from Team Wells Racing on YouTube about building the gear diff and decided to change the original diff gears to the LAW50 diff gears, too.
No I have the problem that when I tighten down the screws from the diff cover the diff gets stuck and doesn't move. I put the original gears back in and everything is fine again.
I measured the gears and found out that the large gear from LAW50 has about 2,5mm thickness and the original one has about 2,3mm thickness.
So how can you get the LAW50 gears to work on the Ultima gear diff?
Thanks!

Using 2 Diff Seals helps this issue.

Thanks, I may try this...not the solution I really like.
He hasn't mentioned this in his video so there must be another way, I hope.

Hi Mark,

I made the video and have never had this problem with LAW50 gears. They can be a bit notchy when new but wear in after a couple of runs. What shims did you use inside the diff? as these set the backlash in the gears and if too thick then will give you what you describe. There are a couple of options:
1. try thinner shims, the standard ones are 0.15mm so try 2x 0.1mm shims and see if this frees it off
2. take the two larger gears and rub the back of them with some fine sand paper
3. use a second gasket to space the casing (I don't like this method either which is why I don't mention it in the video but others use it effectively)

Hope that helps :thumbsup:

Hi.
Thanks for your answer...
The gears were really more than notchy...:cry: I almost couldn't turn the outdrives from the diff. I shimmed the gears as you mentioned in your video and tried thinner ones without success. Put back in the original ones and it was very smooth.
I try sanding down the large gears next time and see if it helps.:thumbsup: