I have a 2001 7.3ltr f350 superduty diesel.

The transmission sometimes doesn't want to shift out of 2nd gear. As soon as I let off on the excelerator it will shift into 3rd gear. I just had the tranny oil and filter changed about a month ago and the oil doesn't smell burnt at all. It doesn't sound like its slipping, it just doesn't wanna shift sometimes.
Thanks for the help!

 

You may want to do a seach on "mechanical diode"
Although that's more of a first to second gear issue,..... IIRC.

 

Actually I havnt confirmed its from 1st to second yet. It's only done it about 6 times and each time I'm not expecting it so I'm still kinda unsure if its from 1st to 2nd or from 2nd to 3rd.

 

That mechanical diode is specific to only the 2001 model tranny. I found out the hard way, same thing. It wouldn't shift out of first but let the motor rev up real high like 2500+ rpm's and let off and it'd shift straight to third. From there on no issues.

Your tranny needs rebuilt, they'll replace that diode with a non mechanical diode called a sprag or something. It was a faulty design by Ford.

 

Not what you wanted to hear, huh? I know man, it sucks. But on the bright side it won't ever happen again.

 

So your saying my tranny is on it's last legs?:-(

 

No, not if you like not knowing if you can make it past 10 mph.

My tranny was in perfect working order, just that diode broke and mine broke, well, I have a picture I'll post here shortly but the teeth literally broke in half.

All of my hard parts (gears) and the torque converter were just fine in mine but the tranny needs to be dropped to repair your issue. Our stock torque converters are not known to be the best either so I took the opportunity to have a billet covered triple disc tc installed, new (rebuilt) valve body, new solenoids, new filter, pretty much an all new tranny. No one will replace the hard parts unless they're needed and most likely it's not.

 

the top sprocket on top of that hunk of round metal disc, the left side is broken off and is laying on the far left in the pic. that just fell out of there. that mechanical diode is in the rear of the tranny.

I don't know how it works but if and when Mark K. chimes in he's the tranny guru and can help you better than I. I just went through this this year.

 

Ok... so what if it's from 2nd to 3rd it doesn't wanna shift? Then what would it be??
I'm gonna try and get it to do it tomorrow and find out exactly but I was almost positive it was from 2nd to 3rd.

 

I can't say, I'm not a tranny expert. I'm not sure if that part is restricted to first to second gear shifts or any gear shift.

 

The mechanical diode is a brand name for a particular one way clutch. When it fails it causes a problem with the 1-2 shift. In rare cases it can affect other shifts because debris from the broken parts can fall into the valve body and stick valves.

 

Great!! So it's just a matter of time till the tranny completely fails??

 

Are you getting a flashing O/D light? Any codes?

My 2-3 shift error was caused by a valve sticking in the solenoid body.

 

My OD button hasn't worked in a couple years, the wire broke off inside and I never bothered to fix it.
I havnt checked for any codes yet either. I will do that before jumping the gun though!

Does anyone know where there is a transmission shop in Edmonton Alberta, that can rebuild me a built proof tranny for my truck??

 

NADP is in Edmonton:



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