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Old Oct 23, 2007 | 07:49 PM
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Mechanical Diode

What year did they use the mechanincal diode in the auto transmissions? I remember reading somewhere to stay away from certain years, as they were prone to failure. It may have been the F150's, though not sure.
Thanks
Rich
 
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Old Oct 23, 2007 | 08:48 PM
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From: Blairsville,Ga
early 2001
 
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Old Oct 24, 2007 | 06:04 AM
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Thanks for the info Ray. Now wonder that 01 crew longbed I'm lookin at is so cheap
 
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Old Oct 24, 2007 | 06:56 AM
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The problem mechanical diodes were only in the diesel Superdutys from the start of the 2001 model year until March, 2001. The gas engine Superdutys didn't have them.

The 4R70W in the F150s have had mechanical diodes for years without any problems.
 
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Old Oct 24, 2007 | 07:57 AM
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Didn't the diesel's uses the same 4R100 Trans?
 
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Old Oct 24, 2007 | 08:01 AM
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I have an early 01' with 115,500 miles on the trans. With what I have in it, I have never had a problem. Just like the rods, I have forged. Does that make the others bad? I think not.
 
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Old Oct 24, 2007 | 11:25 AM
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Originally Posted by Mark Kovalsky
The problem mechanical diodes were only in the diesel Superdutys from the start of the 2001 model year until March, 2001. The gas engine Superdutys didn't have them.

The 4R70W in the F150s have had mechanical diodes for years without any problems.
from what i have heard the gas engines did have them but there was a recall to replace them. the reason there was no reacall on the diesels is (according to ford) the only time there could be a problem is when the trans was seeing more than 4000 rpm. since a "stock" diesel will not rev that high they didnt do anything on the diesel trucks. i cannot confirm this but i have read it quite a few times on othere sites...dono
 
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Old Oct 24, 2007 | 01:05 PM
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It was always my understanding that my '01 V10 had the mechanical diode in question.

And there was no recall or I would have certainly had it done

I know there was a TSB about it ...

Here's one:

https://www.ford-trucks.com/tsb/full...hp?tsb=01-13-5
 
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Old Oct 24, 2007 | 08:59 PM
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Originally Posted by krewat
It was always my understanding that my '01 V10 had the mechanical diode in question.

And there was no recall or I would have certainly had it done
All 4R100s had the mechanical diode at 2001 Job#1. Before ANY were sold all the trucks that were built had their transmissions replaced with transmissions that didn't have the mechanical diode. No V10 or V8 gas engine trucks were sold with a mechanical diode. I was there at Transmission Engineering when this happened. It was a MAJOR disaster.

They decided that they could leave it in the diesels because the only failure mode that was found was above 4500 RPM. Since the diesel couldn't run that fast it was decided to leave them in for a while, until a better time to change. That time came in March, 2001.
 
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Old Oct 24, 2007 | 10:14 PM
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Thanks Mark!

That makes me feel better
 
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