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Old Sep 16, 2007 | 09:37 AM
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4R100 shifting problems

I have a 2001 F350SD, 7.3l 4x4, 160,000+ miles, only mod is an AFE Stage 2. After taking off from a dead stop when I hit 20-25 mph the tranny shifts up, then down, then up, then down and it will keep doing that. Now this started last night while I was babying it thought the city. When you stomp on it or just give it a little more from a dead stop it shifts fine no problem. Is this a line pressure problem for Banks, Sonnax spring kit fix, sensor(s) or something worse and really expensive? I just put my goose neck hitch in for my 30' Featherlite STL to start hauling tractors. Any help would be appreciated. I switched to Ford after 3 transmissions in my Dodge; I hate to go down this road again.
Thank you,
-Jim
<o></o>

<u1></u1> P.S. Fluid level is good, fluid is clean. No fron<st1:PersonName w:st="on">t l</st1:PersonName>icense plate so I can get air to the cooler.<o></o>

 
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Old Sep 16, 2007 | 10:01 AM
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Can't say I have heard of that exact problem before, but what I can tell you is that if that is the original tranny with 160,000 miles on it, it is living on borrowed time. Unfortunately, the tranny is a weak spot of the Ford, as it was with your Dodge. Fortunately, you have a few options to get a trans once, and never again. I got lucky and found a local place that built a pretty decent transmission, but in your case, look at Either John Woods out of HoltVille California or BTS from Lead Hill Arkansas. Either one of those will ensure trouble free shifting for a long time to come.

Does your O/D light on the shifter flash when this happens? It does kind of sound like a line pressure issue.
 
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Old Sep 16, 2007 | 04:11 PM
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Im thinking 01 tranny mechanical diode is finally catching up with him.
 
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Old Sep 16, 2007 | 04:31 PM
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Originally Posted by bdrummonds
Im thinking 01 tranny mechanical diode is finally catching up with him.
I agree, as stated the trans is still the weak link
 
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Old Sep 16, 2007 | 08:22 PM
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I dont want to hijack this thread.Just wondering was that diode in any other years than 01?

Originally Posted by bdrummonds
Im thinking 01 tranny mechanical diode is finally catching up with him.
 
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Old Sep 16, 2007 | 08:37 PM
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Originally Posted by dryfly
I dont want to hijack this thread.Just wondering was that diode in any other years than 01?
No. I didn't explain that very well. 99-00 the shift diode was electrical. 01 they up and changed to mechanical, which turned and bit them in the butt. There was a TSB out about it in 02-03. in 02-03 they went back to the elctrical diode and the problems were FAR less. the thing about the 01 Mech diode is you really don't know its going bad until it does read: one morning its fine that afternoon it starts not wanting to shift from 2nd to 3rd, or 1st to 2nd, and at some time it will shift to a gear and then its there, it will not come out of that gear.
 
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Old Sep 16, 2007 | 08:58 PM
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Thanks for the info.Wasn't clear about that diode stuff.
 
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Old Sep 16, 2007 | 09:07 PM
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I dont think 160k miles is pushing these tranny's, my friend has an 01 f350 with 390k miles on it, original trany and still no problems, thats a little crazy but still i just got rid of my 1992 f250 with 260k miles on it, original tranny as far as i was told when i bought it with 200k miles on it, and trans was fine, just starting to shift a little hard. And i just bought a 01 f250 with 160k miles on it, original trans, and rides amazingly smooth. all diesels by the way.
 
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Old Sep 16, 2007 | 09:16 PM
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Originally Posted by DemonRace6
I dont think 160k miles is pushing these tranny's, my friend has an 01 f350 with 390k miles on it, original trany and still no problems, thats a little crazy but still i just got rid of my 1992 f250 with 260k miles on it, original tranny as far as i was told when i bought it with 200k miles on it, and trans was fine, just starting to shift a little hard. And i just bought a 01 f250 with 160k miles on it, original trans, and rides amazingly smooth. all diesels by the way.
Demonrace6,
I agree with your statement, I have 246K on my original unmolested tranny. i don't baby it, tow heavy and hard, and she keeps commin back for more.
BUT. In 01 the Mechanical Diode was and is and issue. Some were repaired by FOMOCO under the TSB, some were not. Get an Oasis from your local dealer(or up in the 6.0 forum) and look to see if your tranny has been fixed or replaced by FOMOCO.
 
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Old Sep 17, 2007 | 08:57 AM
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I recently rebuilt my '01 trans (at 126k miles) and the "mechanical diode" was still O.K. The mechanical diode is a ratchet type one way clutch and a sprag type uses spring loaded rollers and a ramped cam to do the same thing. I did however upgrade to a new direct clutch drum and HD sprag to replace the diode. The problem, I found, was the center support bearing failed and and caused parts to wear together and create a lot of grindings in the fluid. Also, the sealing rings on the forward clutch drum could not be held centered and was "floating around" in the center support housing. BTW, the clutches looked perfect when I tore it down.
 
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Old Sep 17, 2007 | 11:23 AM
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Here's the diode TSB
 
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Old Sep 17, 2007 | 02:15 PM
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Originally Posted by bdrummonds
99-00 the shift diode was electrical.
Wrong.

The mechanical diode is a type of one way clutch. Before 2001 the intermediate used a sprag type one way clutch. For 2001 they changed to the mechanial diode, which is just a trade name for a different design of one way clutch. Midway through the 2001 model year they changed back to the sprag one way.
 
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Old Sep 18, 2007 | 09:52 AM
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Originally Posted by DemonRace6
I dont think 160k miles is pushing these tranny's, my friend has an 01 f350 with 390k miles on it, original trany and still no problems,
Not every 01 has that diode. Just some lucky ones.
 
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Old Sep 18, 2007 | 09:54 AM
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Does the fluid smell bad or burnt?
 
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Old Sep 18, 2007 | 10:20 AM
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Originally Posted by Mark Kovalsky
Wrong.

The mechanical diode is a type of one way clutch. Before 2001 the intermediate used a sprag type one way clutch. For 2001 they changed to the mechanial diode, which is just a trade name for a different design of one way clutch. Midway through the 2001 model year they changed back to the sprag one way.
You're right Mark, brain fart on my part....
 
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