Will a 2 wd at fix a 4 wd at

First I would check the PowerTrain Control Module for any thrown diagnostic troubleshoot codes by using a code reader.
I am unsure if there is a separate transmission computer module for your vehicle. If there is, a code reader will be necessary.
I will assume that the "check engine light" or MIL did not illuminate or the 4wd or 2wd light flash since you did not mention it.
If the car can move forward and backward in 4wd, then it's not the transmission itself since power is transferred through the output shaft of the transmission to the transfer case.
I would think that 4-wheel drive mode is not fully disengaging-
Check the vacuum hoses for damage, crimps, or leaks
Check and test the vacuum actuator
check and test the transfer case switch
check the vacuum actuator cable for damage or defect
check and test the encoder motor actuator on the transfer case
Buy a repair book or shop manual specific to the year, make, and model of the car you are having problems with that offers descriptive troubleshoot and repair procedures with illustrations. You can purchase them as soft or hardcover books or electronic downloads. Here are a few publishers, Chilton, Haynes, Motors, etc. Do an online search or go to your local auto parts store.
Otherwise, if you are not savvy in automotive diagnostic & repair, I would highly recommend flat-bedding the vehicle to a reputable transmission repair shop that has ASE certified transmission technicians. The reason you need to place your vehicle on a flat-bed car carrier - is to avoid serious damage to the transmission.

remove the entire shaft from the diff and transmission
if it is a front shaft no problem
if it is a rear shaft then you will require 4 wheel drive operation
it would be best if you simply fixed the problem with new "U" joints

it is on the drivers side of transmission where the shift cable goes to transmission it will have a electrical plug going to it.

The speed sensor is located out on the transmission extension housing (tail housing), and there can be two different types of sensors used.

Here are some images both 2-WD and 4-WD to help assist you, and let my know if you require any further assistance.


Speed Sensors.







2 Wheel Drive Transmission.

4X4 Transmission and Transfer Case.

Not knowing the specifics for your truck are (2 wd, 4 wd, engine size, reg cab, extended or crew, gear ratio etc)

I'm giving you a ball park on the towing limits, they'll be within 500# of the towing limit.
2 WD
2.8 L 5500-6000#
3.5L 7000-7500#
3.5L automatic transmission w/3:73 gears 8000-8500#
4 WD
2.8L 6500-7000#
3.5L 7500-8000#
3.5 L automatic transmission w/3:73 gears 8500-9000#

Remove the trans pan and you will find it attached to the valve body

Well we don't know what size engine your vehicle has or weather it is a auto transmission or manual but here are the capacities.
Auto transmission
4 speed- 4wd 7.5 quarts
4 speed 2wd 7.8 quarts
Manual transmission 2 wd 4.0 quarts
Manual transmission 4 wd 3.2 quarts

this information is for 2.0L 4 cylinder engine code (C) DOHC
if you need information for 1.6L then send me a message back and I will give you the info.

Have you topped up your transmission fluid yet?

Automatic trans??? 2 or 4 wheel drive??
AOD 2 wd- 12.3 qts
AOD 4 wd - 12.3 qts
C-6 2 wd - 12.0 qts
C-6 4 wd- 13.5 qts
E40D 2 wd 15.7 qts
E40D 4wd 16.2 qts
4R7OW - 14 qts

Try putting transmission in neutral, not park, then transfer case to 2 wd or 4 high, then transmission into gear.