How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Gary Your Own Question
Gary
Gary, ASE Certified Technician
Category: GMC
Satisfied Customers: 15701
Experience:  GCM master tech over 25 years
19513769
Type Your GMC Question Here...
Gary is online now
A new question is answered every 9 seconds

I have a 86 sierra that only operates in reverse

Customer Question

I have a 86 sierra that only operates in reverse
Submitted: 1 year ago.
Category: GMC
Customer: replied 1 year ago.
1986 Gmc Sierra Classic auto trans. Literally drove it and parked, went to move it and only will back up. Fluid level is fine
Expert:  Gary replied 1 year ago.

I am sorry for the long wait and that you are having this problem

is the transmission physically being shifted into drive ? and it just acts like neutral ?

is this a 4WD ?

Customer: replied 1 year ago.
not 4wd, yes the selector moves it into forward gears, with the wheels up they start turning but it doesn't have the power to drive the vehicle. fluid is not burnt.
Expert:  Gary replied 1 year ago.

with reverse working fine we know the fluid is full and the transmission pump is good and making good pressure since reverse works

with it not moving the truck forward when forward is selected is going to be an internal failure going on of the forward clutches or possibly the one way clutch inside the transmission

the shift solenoids or valve body would not cause this problem but something inside is slipping or not being able to apply a forward gear

I am sorry to say this transmission will need to come out and apart to be repaired and usually ends up being a rebuild to correct this issue

a lot of times it is a lot cheaper to just pick up a used transmission for a junk / salvage yard and just swap it out into your truck

Related GMC Questions