tranny slipping

[BroncoKID34]

is there a vacuum line or something that runs to a module or something b/c the tranny is slippin' after 2nd but once it finds third it stays there....what could this be

 

[Stan]

Most auto trannys use a combination of vacuum and valving to determine gear selection based on vehicle speed and engine load. The E4OD is electronically controlled, so the trucks ECU is handling all of the shifting decisions. I would start with the simplest route first. Get a new tranny pan gasket, new filter, and several qts. of the appropriate fluid. (check your owner's manual or Haynes manual for capacities) It never hurts to have a new fluid change on your list of things you've done. Plus, if you take it to a tranny shop that's the first thing they'll check. (fluid level and condition)

Good luck,

Stan

 

[miesk5]

& do you have a CEL?

if so, ck for EEC-IV Diagnostic Trouble Codes by Ryan M

http://fordfuelinjection.com/?p=13

 

[firelt90bronco]

The old school way of checking if a tranny is slipping is to drop the pan and change the filter. Take the old filter and old oil and check for chunks of metal (gear teeth).