gpilethbridge

I put in all steel gears in my stampede xl-5(Magnum 272 Tranny) because I'm upgrading to brushless. Now, the truck wont accelerate very good or go very fast anymore. All was good before I installed the steel ring gear with the diff inside, and the steel idler gear. All I think is that I put the wrong type of or thickness, or just too much grease inside the diff. I used wheel bearing grease. Would too much, or too thick a grease inside the diff(has 4 planetary gears with 2 sun gears) slow down the truck to the point where it is very noticeable? The motor(Titan 550) was fine before I installed the gears, and still is, and no other mods have been done. I only have had the truck for 2 weeks. The other two gears mesh very smoothly, no problems there. Any ideas would be greatly appreciated!!!!