Skip the auto shop - Our mechanics make house calls

Q: Put a new transfer case on, now tranny won't shift out of first unless I do it manually

asked by on

I replaced my transfer case bc the old one was busted and leaking transmission fluid. I put the new one on. When I put it in drive, the transmission will not shift out of first. However, I can manually shift from first to second. It won't go past second gear. Reverse works fine as well. The speedometer and odometer are not working, and the ABS light and parking brake light stay lit. My transmission was fine before I changed the transfer case. I believe it is electrical. Please help!

My car has 250000 miles.
My car has an automatic transmission.

A: Hi there, thanks for writing in about your ...

Hi there, thanks for writing in about your 2000 GMC Sierra 1500. Your transmission and ABS system need a vehicle speed reference to operate correctly. The transfer case has two speed sensors located at the rear extension housing. Inspect the wiring to the sensors. If it looks good and is undamaged, you could try removing the sensors from original transfer case and installing them in the replacement. The transfer case speed sensors put out an A/C voltage when the driveshaft is rotating. If there is no voltage, something internal is wrong with the transfer case. To have this issue addressed, I recommend having a qualified professional, such as one from YourMechanic diagnose the shifting issue in order to have this corrected.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I replaced my clutch and bleed my hydraulic clutch master cylinder. But when I put the truck in 2H and try to shift, I won't shift.

Hi there. There seems to be an issue with the transfer case on your vehicle. The transfer case may have a bent fork or the shifter synchronizer has broken teeth. I recommend seeking out a professional, such as one from...

Q: Sporadic issues with eletrical system of the car

Your vehicle has many technical bulletins that pertains to wiring issues with pins and connectors to various modules and control units in the vehicle. This issue is one that is hard to track down since it is an intermittent connection...

Q: Driver side low beam and taillight not working.

Hi there. The headlight bulbs got burned out due to the wires touching. Replace the low beam headlights and the taillight bulbs as they probably burnt out from the short in the system. If the bulbs are good, check the...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...