ok so I have a 2002 f250 7.3l diesel automatic, when I first test drove the truck the o/d light was flashing told the dealer to fix or I was not buying, they fixed the problem well they stated they did!! transmission will downshift when taken out of o/d if you depress the gogo pedal. but it will not hold the gear if you let out. The first time I noticed it is when towing our trailer down a 6% grade and needed a little help slowing down when I pressed the o/d off it dropped the rpm all the way to idle. The truck is really lacking power for towing as well. It does amazing unhooked plese help! We are going camping in two days.

 

no codes from my sct chip, fluid is clean was changed 7000 miles ago with the filter.

 

Will it engine brake with the shifter in 2, or does it go to idle speed there, also? Try this at 40 MPH.

 

Mark-

first off takes for replying, yes it will engine brake in 2nd gear.

 

Since it does engine brake in 2, but not with the OD turned off, you have either a bad coast clutch solenoid or a bad wire to the coast clutch solenoid. The solenoid applies the coast clutch when the shifter is in D and the OD is turned off. A hydraulic circuit bypasses the solenoid to turn on the coast clutch when the shifter is in 1 or 2.

Since you have engine braking in 2 the coast clutch is working.

 

Mark-

Is this something I can fix or am I am i going the the dealer, were is it located at.

 

ok some new news with the trailer hooked the truck will not hold or slow down in 2nd if put in manuel. Is my transmission going or ??

 

Hey 429 I have the same problem in my 02 F350 7.3 which I bought about a year ago mine still engine brakes in manual though let me know if you get it figured out I'll do the same if I ever find time to get to it

thanks

 

That implies that the coast clutch has come apart. It's a mechanical failure that will require the trans to come out and get torn down to fix.