Use the DT gear diff. Better than useing the locker.
Heres a previous thread about how to swap it.
"For the MF2 u will need part# 2919,2930, tranny screw set for desert truck, these 3 parts are specific for the desert truck, t-plate for xxxt or cr, rear pivot block for xxxt or cr, idler gear, upper shaft and bearings for xxxt or cr, motor plate an gear cover for xxxt or cr..... on the MF2 u need to replace the dogbones with bones that are .215 longer, not sure about the cr dogbones."
Posted on another forum. Some of these item you probably already have. This list is for those with a standard XXX-T or the CR version. The MF version needs a couple of other items(explained in the link above) since the tranny is different.
LOSA3124 Spring, Cup, Spacer & Wash: Hydra - You don't need the silver spring only the gold one.
LOSA3983 82T 48P Kevlar Spur: XXX/T
LOSA9930 Alum Upper Gear/Shaft 2.19:1 all XXX
LOSA3132 Slipper Backing Plate (x2)
LOSA3123 Slipper Friction Pad (x2)
LOSA3608 4-40 Steel Locking 1/2 Nuts (10) - You just need one, but hey spares are nice to have.
LOSA2919 Transmission Case, Gear Diff Only: DT - Gotta have this.
LOSA2930 Diff Set, Complete: DT
Diff (XXX-T CR):
LOSA3041 XXXCR Motor Plate
LOSA3079 Idler Gear Set: XXXCR/XX Buggy, SPT - This comes with two gears, you only need one. Unforunately it does not come with the shaft, see LOSA2937.
LOSA2937 Idle Gear 32T & Shaft: XX/Gen II - This comes with a gear and shaft. Use the shaft, the gear does not work with the DT diff.
LOSA6909 1/8" x 3/8" BB (XX Trans)
LOSA6903 Sealed BB, 3/16x3/8
LOSA6908 1/2" x 3/4" Sealed BB
LOSA3065 Losi Diff Lube
LOSA3034 Tranny Screw Set: XXX, XXX-T, SPT"