A dab of silicone sealant like clear bathtub or clear marine caulk in the holes?

yes i have a temp gun. i dont run my truck for more the 5 to 6 min and the motor is cold. i need to pick a day and play with it more

Take you belt off and gear up a couple of teeth and add some timing on the speedo. Stop running when the motor gets hot. This type of RC is not really designed for speed runs though.

theres no timeing in the esc at at all its a sportman class

Go 13 and run for 3 min then check temp. if you are at or lower than 160 at the back side of the motor that gets less air to cool it, go another 3 or so min, keep running and checking temps till the lipo voltage triggers the esc to cut off and if you can run a full pack without getting up to 150, try a 14 tooth. If you are close to 160, 13 tooth is as high as you can go and your done.

What is the best way to clean out all the old diff fluid when rebuilding? Is simple green ok for this?

I wipe out as much as I can with a paper towel and then use brake cleaner.

I use a very light weight shock oil (20w) to help get the old diff fluid out faster, just drop in some shock oil then mix it up by rotating the outdrives and then empty it out. Usually takes about 2-3 times of doing this and you pretty much got all the old fluid out, then I spray it down with Cow rc's cleaner/degr. product and wipe it down and it comes out looking almost brand new.....

Your ex-girlfriends tooth brush...

Wait, you said this was speed runs on the street. Are you drag racing in a sportman class with a short course truck? What exactly are you trying to do.

Cameron, What did you do to lighten up your truck?

on not raceing the esc is for sport man class. i just play in the street in the house here. sorry

OK, guys got to race yesterday, very frustrating day for me. I need some setup help. I was on our outdoor 1/8 scale track (200 x 125). VERY dry, something about the well drying up so no water. It's a Clay/Dirt mixture. The groove was ok, but if you got out of it, you were in the pebbles. My main problem was with my back end kicking out on me. I also had issues getting through the quad. No way I could make it, especially since it's going up hill! I had to double/double it.

I tried to post my setup sheet, but it's too big to attach so here's what I got:
Original Kit truck
RX8/Novak Ballistic 4.5T (Not HT version) Geared 12/60
RCShox V2 Center Diff (5 pins) and Ackerman bar (set to 2nd hole from front)
2.2 Front Sway and 2.0 Rear Sway bars
Camber: Front -0.5
Rear +0.5
Toe: 4*. (My rear toe is 8*, is that normal?)
Ride Height: 21.5 all around
Ballstud Placement: Front, outside with 2MM spacers
Rear, inside with 2 MM spacers
Rear Toe Block: 3-2
20T pulley front and rear
Tensioners set to Hole 4 front and rear
Shock Towers: Hole 2 front and rear
A-Arms locations: Outside front and rear
No Washers or Bumpsteer Washers on the arms
Rear Hub Location (stock hub): A, or inside hole
Shocks: Running Bladder, original kit shocks
Front - Blues with 1 limiter, 25Wt
Rear - Front Whites with 3 limiters, 30 wt
Using original stick pack setup (right hand side)
Diff Fluids: Front 7, Rear 5
Tires: Proline Hole Shots front and Rear, M3 compound, JConcepts Hazards
Wheels

Upon inspection today, I found that both my diff's are wobbly as hell. I got 1 diff rebuild kit, waiting on another. Question here is should I plan on shimming using the 0.3 MM washers, or try the Bearing Mod on Ultimate RC? I got an extra case and the 5x10x3 bearings. I will also be replacing the big outer diff bearings with Avid Racing ones.

Lay it on me guys, let me know what you think and where I can make improvements. I was dead last in qualifying yesterday, although it was only my second time racing. I probably should have been in the Rookie class, but didn't think I would be that bad! The Losi's were dominating yesterday

Trimmed lots of fat. I run a RS pro and 540 2pole motor so right there my truck is lighter that most. I use Murfdogg 4600 saddle packs so they are lighter than the bigger packs. Instead of adding weight to the front I removed the rear bumper, except the skid plate part. My Method RC bodies are thinner so I used my body that does not have a wrap on it (3oz lighter). Trimmed down some on the front bumper and side bars. RPM front and rear arms are lighter. Mine is not a FT kit so I have some aluminum I could add still.

Good to know, Thanks!