what would be a good oil or grease to put in the diff on a summit?
I have a mamba monster 2

7000 front and 2000 back
or heavier if you want remember the truck has huge tires

stock is 100k, I put 50k on front,and 30k on rear

thank you I will try that

Just curious, why different on the front and rear?

what is the positive and negative of running heavier oil in it

thank your for giving information.

It doesn't matter what diff oil you're using when the diffs are locked.

Since the front is the lightest part of the truck, usually you put heavier oil at front to get more traction.

You don't run with the diffs locked at all times, specially if you run a brushless systems, it will destroy the diffs.

do I fill the diff up all the way up with the oil

You fill them almost to the top as the spider gear on the ring gear side will displace some of the fluid. If you put too much in the excess will just be pushed out. But yeah you want them filled

thank you to all of you

IMO a brushless system shouldn't ever be used in a Summit in the first place, it defeats the whole purpose of owning a Summit.

If you're using a Summit for it's intended purpose, when the diffs are open and you can't get over something like a rock or a log you lock them up.

BTW I've done plenty of bashing with a permanently locked rear diff in my BL E-Revo and the only thing I've busted is driveshafts.

what do I put in my ring gear