Runs jurky put in new drive motor. now at low speeds it runs jurky or studdering when you use it. how do I get the jurkyness out?

Which do you have ?
Transfer Case - NVG 236 (Two Speed Automatic)
Transfer Case - NVG 233-NP1 (Two Speed Selectable)
The NV236 transfer case is an automatic transfer case with three drive ranges. Shifting from rear wheel drive to four wheel drive is done automatically when the transfer case shift control module receives wheel rotating slip information from the speed sensors. The transfer case shift control module then engages the transfer case motor/encoder to position the transfer case from rear to four wheel drive. When the transfer case shift control module receives information that the wheel rotation is the same on both axles, the transfer case shift control module sends position information to the motor/encoder to put the transfer case back into rear wheel drive. The three drive ranges are 2HI, 4HI, and 4LO. The 2HI position is for normal driving with the rear wheels pushing the vehicle. The 4HI, position is for driving through sand, snow, mud, gravel, or heavy rain at normal or slightly below normal speeds. The 4HI engages the front axle to allow for four wheel drive. The front axle is pulling the vehicle, and the rear axle is pushing the vehicle. The 4LO range is used for off road driving, heavy snow, deep mud, or shallow fording. The 4LO is similar to the 4HI except that the gearing in the transfer case is set for low speed and high torque. The NV236 is manufactured at Syracuse New York by New Venture Gear a division of New Process Gear for General Motors.
Is the switch light on or flashing ? If you have automatic 4x4 there are several DTC'S that can set >
DTC B2725 ATC Mode Switch Circuit Malfunction DTC C0300 Rear Speed Sensor Malfunction DTC C0305 Front Speed Sensor Malfunction DTC C0308 Motor A/B Circuit Low DTC C0309 Motor A/B Circuit High DTC C0310 Motor A/B Circuit Open DTC C0315 Motor Ground Circuit Open DTC C0323 T-Case Lock Circuit Low DTC C0324 T-Case Lock Circuit High DTC C0327 Encoder Circuit Malfunction DTC C0362 4LO Discrete Output Circuit High DTC C0367 Front Axle Control Circuit High DTC C0374 General System Malfunction DTC C0376 Front/Rear Shaft Speed Mismatch DTC C0387 Unable to Perform Shift DTC C0550 ECU Malfunction DTC C0611 VIN Information Error

Motor overheating,check waterpump

Couple of things....fuel filter could be pretty clogged....fuel pressure regulator is bad....
To make a better fix for you, can I get the info about your vehicle? Year/model/engine size?
Thank you.

Pull alternator and take it to have it bench tested.

The blower motor has 2 relays, one runs low and med speeds, the other runs high.

sounds like you have a miss fire like bad plugs plug wires

Check the exaust backpressure before the cat converter. Should be less than 1lb. Write back.

If the motor is still turning, good. It is not burned out. IF the motor is not turning with the unit on, it is either a reset switch (not all units have them) or the motor is burned out. New motors need to have the pulley adjusted so it is not too tight or not too loose.

Dead sparkplug or plug wire. Vacuum line disconnected , loose or broken,or timing / timing belt.

Chances are, you've smoked the motor. You basically put 120 volts across the speed windings of the motor when you did this.

What you need to do is, with the new motor, you will have neutral, and speed 1, speed 2, speed 3, etc. Hook one of the original black wires to neutral (it would be best to trace which of the two black wires is connected to neutral, and connect this one.).

Black on the new motor is probably High speed, red is probably low, orange is medium speed. Hook the remaining black wire to one of these, and no more than one of these, or you will smoke the motor again.

Attach a wire cap and/or electrical tape to the remaining wires to insulate them from contacting anything else.