first real RACE truck i got just a week or so ago. Never messed with R/C differentials or ne thing like this. REad that need to put diff fluids in the rear end, opened the main case, filled er up. Put it all back together with a feeling of accomplishment. I left the shop and was headed to town for something, thinking bout the situation, dawned on me that where i had put the fluid wasnt doin sheet, just slowin the car down if ne thing hahahah, had to go back, take the care back apart, drain and clean the oil out, then open the spider gear box, and start over hahah.