Greetings,
My 1987 f-150 broke a serpentine belt and I replaced it but now the truck will not go into third gear.

Is it possible that when the belt broke it may have knocked something loose or damaged something else? Is it possible that a breaking belt could damage the tranny?

 

Auto or stick?

 

It's an Automatic

 

I'm not sure if this would do it, but if the belt flew around it might have mashed the cooler lines shut.

 

is the shifter stuck in 3rd gear or is the tranny stuck in gear? if the tranny is stuck in 3rd then try sfifting gears and see what it does

 

nevermind miss read sorry

 

1987 / auto trans = C6?

Vacuum line damaged?

Back of the motor or should be, section of the belt not accounted for as in lost under truck? make sure all vac lines are intact including line to vac modulator.

If its a C6.....

 

Good idea. I've been trying to think of what could be up front that the belt could damage and make it not shift. Hope he figures it out and lets us know. This one is bugging me....................

 

Danr1 Sorry I am one of those not very mechanic savvy guys. Where is the Vac Modulator located? I found pictures of it on line but it doesn't list the location in the truck.

 

Down on the trans but was more speculation with a question to get you to identify exactly which transmission you have.

"F150" more likely to have the AOD?

If so its controlled by a cable instead, vacuum line for C6 or TV cable for AOD and both down back of motor not going to say impossible but unlikely to be damaged by a failed accessory drive belt up on the front of the engine.

Use the below trans pan chart to identify your trans,

Ford Transmission Pan Shapes

Might be failed vac line might be it broke a tv cable clip might be something else, its throwing the accessory belt same time might be pure happenstance hard to say at this point.