Need some quick Tranny help...oh boy..
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Need some quick Tranny help...oh boy..
This is weird...it's the 01' f250 4x4 in my sig...truck works perfect 1st through 2nd, once it attempts to shift into third it feels like your pressing the brakes almost...pulls the whole truck down, won't complete the shift. I pull it into 2nd gear and all is well. fluid nice & pink and full..no noises at all...was just cruising around empty (not driving hard at all)
First symptom i felt was it went to shift into 3rd...felt like the TC didn't lock..slipped a bit then shifted into 3rd, then after that it is doing what is described in the first paragraph...Am I toast or is it something electronic (what i am hoping)?
First symptom i felt was it went to shift into 3rd...felt like the TC didn't lock..slipped a bit then shifted into 3rd, then after that it is doing what is described in the first paragraph...Am I toast or is it something electronic (what i am hoping)?
Frmr Ford Trans Engr
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From: SE Florida
A mechanical diode failure should cause a problem with the 1-2 shift. It should not affect the 2-3 shift. Also, there shouldn't be a mechanical diode in a gas engine transmission. Several thousand gas engine trucks were built with the mechanical diode at the start of the 2001 model year. Supposedly all those transmissions were changed before the trucks were sold. I have heard stories that some slipped though.
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Hi Mark, I'm happy u chimed in. My truck is a 7.3, not gas...I scoured the web and found alot of feedback and it seems the 2-3 shift has failed by the diode too. I read the same thing initially, the ford TSB actually stating the 1-2 shift however from what i've read it appears their has been some confirmed diode failures (tore trans apart) w/ my symptoms as well. If u believe it could be something else I am all ears, this happened suddenly w/ no stress on the truck and the OD light isn't flashing. Thanks for any ideas. Bob
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Hard Shift from 2nd to 3rd
I'm experiencing a similar problem, have a 1999 F350 4X4 7.3 PSD, SRW, no engine or chip upgrades that I'm aware of (bought it used 6 months ago) I notice randomly during the day (mostly when the engine is cold or cooler) my truck hangs in 2nd gear at approx 2200 RPMS with 1/4 to 1/2 steady throttle, white smoke blows out for the duration of the hold, then a jerk/hard shift into 3rd gear, unless I really get on the gas 3/4 throttle it runs through all the gears with no problem and no white smoke.
Just got it back from the mechanic for a ICP sensor and rear pinion seal repair and described these symptoms before I dropped off my truck, the mechanic said he couldn't figure out why/how these symptoms were happening.
My research has lead me to believe it is a shift sensor? Thoughts?
Just got it back from the mechanic for a ICP sensor and rear pinion seal repair and described these symptoms before I dropped off my truck, the mechanic said he couldn't figure out why/how these symptoms were happening.
My research has lead me to believe it is a shift sensor? Thoughts?
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Frmr Ford Trans Engr
Joined: Aug 1999
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From: SE Florida
I don't know what a shift sensor is. 
I would look at the engine, not the trans. I think it isn't shifting because the truck isn't going fast enough because the engine is losing power, hence the smoke.
I would look at the engine, not the trans. I think it isn't shifting because the truck isn't going fast enough because the engine is losing power, hence the smoke.
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makes sense, thank you Mark. Any thoughts as to why I would lose power? the shop did the "buzz test" and found no problems w/ injectors. Maybe just as simple as running the RPMS higher with more accelerator on take off?
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mattri
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Aug 2, 2010 09:20 PM