Diode - Don't think it's the issue - What now?
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New User
Joined: Aug 2010
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From: Waynesboro
Diode - Don't think it's the issue - What now?
Posted desc of my issues last week and everyone opined that it was probably the diode. However, drained the fluid and dropped the pan last night. Fluid was clean and inside of pan was the cleanest I've ever seen. There was a tiny bit of metal on the magnet, within the greasy/oily residue you normally find in a pan. However, the greasy/oily residue was limitted to being on the magnet only. The only code I'm getting is P0781.
How do you rule out the solenoid pack, valve body sticking, vehicle speed sensor, TSS/OSS sensor, etc. as the cause. I obviously don't want to throw unnecessary parts at it.
Pls help me.http://images.ford-trucks.com/forums...ies/newbie.gif
Background info.:
V10 4wd Ltd w/ 114k miles built 11/00 & tag on trans indicated the same. 1st gear winds out to between 3500 & 4000 RPMs before shifting to 2nd which is accompanied loud squeeling noise. OD light has flashed as well. The only code I'm geting is P0781. I checked the steering column and the wires are not worn. I'm also not having any issues with blown fuses.
Mechanic buddy hooked up his Snap-On computer reader & test drove. From monitoring the trans during acceleration, 2nd gear tries to engage at the proper time, but 1st gear doesn't disengage until late preventing that from happening.
How do you rule out the solenoid pack, valve body sticking, vehicle speed sensor, TSS/OSS sensor, etc. as the cause. I obviously don't want to throw unnecessary parts at it.
Pls help me.http://images.ford-trucks.com/forums...ies/newbie.gif
Background info.:
V10 4wd Ltd w/ 114k miles built 11/00 & tag on trans indicated the same. 1st gear winds out to between 3500 & 4000 RPMs before shifting to 2nd which is accompanied loud squeeling noise. OD light has flashed as well. The only code I'm geting is P0781. I checked the steering column and the wires are not worn. I'm also not having any issues with blown fuses.
Mechanic buddy hooked up his Snap-On computer reader & test drove. From monitoring the trans during acceleration, 2nd gear tries to engage at the proper time, but 1st gear doesn't disengage until late preventing that from happening.
Posting Guru
Joined: Jun 2005
Posts: 1,268
Likes: 8
From: central Louisiana
ok here's a test trial for ya.
most ford transmission will allow you to manually keep the truck in 2nd gear when you shift into that gear. meaning if you shift into 2nd gear at a stop light your truck will take off in second gear, not 1st.
try this. clear the code (either with a tool, or unhook the batt for a couple hours). check and make sure the code is cleared. drive the truck, and manually shift the truck. put the truck in 2nd, and slowly accelerate, shifting threw all the gears, when you start to slow down, manually down shift threw the gears (EXCEPT FOR 1st!!). if you can check for codes again. if there are none, then take tthe truck out driving it normally letting it shift its self.
if the code comes back, i'd suspect you have a shift solenoid going out.
most ford transmission will allow you to manually keep the truck in 2nd gear when you shift into that gear. meaning if you shift into 2nd gear at a stop light your truck will take off in second gear, not 1st.
try this. clear the code (either with a tool, or unhook the batt for a couple hours). check and make sure the code is cleared. drive the truck, and manually shift the truck. put the truck in 2nd, and slowly accelerate, shifting threw all the gears, when you start to slow down, manually down shift threw the gears (EXCEPT FOR 1st!!). if you can check for codes again. if there are none, then take tthe truck out driving it normally letting it shift its self.
if the code comes back, i'd suspect you have a shift solenoid going out.
Super Moderator
Joined: May 2004
Posts: 29,380
Likes: 118
From: Central Coast of CA
I posted in that other thread it could be your shift solenoid or dirt (or crud or something) gumming up your valve body, but you've got me wondering: You've eliminated the Mechanical Diode (one way clutch) as the culprit, but you haven't said how you eliminated that as the possible problem.
Was it based solely on the condition of the fluid and the minimal amount of metal flakes and shaving on the pan magnet?
Stewart
Was it based solely on the condition of the fluid and the minimal amount of metal flakes and shaving on the pan magnet?
Stewart
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,695
Likes: 2,616
From: SE Florida
I'd eliminate the mechanical diode since there wasn't one in a V10 transmission. It still could be the intermediate one way clutch, the mechanical diode was just one style of an intermediate one way clutch.
Will it shift 1-2 if you manually move the shifter from 1 to 2?
Will it shift 1-2 if you manually move the shifter from 1 to 2?
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New User
Joined: Aug 2010
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From: Waynesboro
In response to STEWART_H's comments above, in my mind, I eliminated the diode as the culprit because of what I read here and in other forums via yahoo searches was that if it was the diode, the fluid would be dirty and smell burnt and there would be plenty of evidence in the pan. Of course, I'm hoping the diode is not the cause for my problems.
Was that an incorrect assumption to be made?
I haven't removed the solenoid pack or the valve body yet. Plan to put new filter in, top off the fluid, and try what TeamMudd mentioned above first and plan to investigat the other suggestions as well. Was sick today and got nothing accomplished on the X or otherwise.
I really appreciate everyone's comments and hope to find the answer soon. Please keep the responses coming and I will let you all know what I find.
Was that an incorrect assumption to be made?
I haven't removed the solenoid pack or the valve body yet. Plan to put new filter in, top off the fluid, and try what TeamMudd mentioned above first and plan to investigat the other suggestions as well. Was sick today and got nothing accomplished on the X or otherwise.
I really appreciate everyone's comments and hope to find the answer soon. Please keep the responses coming and I will let you all know what I find.
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Super Moderator
Joined: May 2004
Posts: 29,380
Likes: 118
From: Central Coast of CA
I'd eliminate the mechanical diode since there wasn't one in a V10 transmission. It still could be the intermediate one way clutch, the mechanical diode was just one style of an intermediate one way clutch.
Will it shift 1-2 if you manually move the shifter from 1 to 2?
Will it shift 1-2 if you manually move the shifter from 1 to 2?
In response to STEWART_H's comments above, in my mind, I eliminated the diode as the culprit because of what I read here and in other forums via yahoo searches was that if it was the diode, the fluid would be dirty and smell burnt and there would be plenty of evidence in the pan. Of course, I'm hoping the diode is not the cause for my problems.
Was that an incorrect assumption to be made?
Was that an incorrect assumption to be made?
Stewart
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,695
Likes: 2,616
From: SE Florida
I have heard some people on this forum say they had one in a gas engine truck. I suppose it is possible if the truck was a very early build, meaning only trucks built in July, 2000. This one is later than that and I'm sure it does not have a mechanical diode.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,695
Likes: 2,616
From: SE Florida
I didn't test them directly. That was someone else's job.
In general, they are first tested at the component level. They will have voltage spikes, high currents, etc. They will be installed on a test stand and run millions of cycles from low pressure to high pressure, or on/off for shift solenoids. There will be high and low temperature tests, vibration tests, shock loads, etc.
Transmissions will be run on dynamometers for very long durability tests. The dyno simulates drive cycles that were recorded on test vehicles in the real world. These tests run 24/7 and take several months to complete.
Full prototype vehicles are built and many are run on a vehicle durability testing, primarily at Ford test tracks. Some testing is done on public roads, too, especially on some hot, steep grades out in Arizona.
The part I worked on most of my career was calibration. I was part of a group that programmed when the shifts happen, and how hard/soft those shifts were. Later I worked on transmission cooling across all Ford vehicle lines.
In general, they are first tested at the component level. They will have voltage spikes, high currents, etc. They will be installed on a test stand and run millions of cycles from low pressure to high pressure, or on/off for shift solenoids. There will be high and low temperature tests, vibration tests, shock loads, etc.
Transmissions will be run on dynamometers for very long durability tests. The dyno simulates drive cycles that were recorded on test vehicles in the real world. These tests run 24/7 and take several months to complete.
Full prototype vehicles are built and many are run on a vehicle durability testing, primarily at Ford test tracks. Some testing is done on public roads, too, especially on some hot, steep grades out in Arizona.
The part I worked on most of my career was calibration. I was part of a group that programmed when the shifts happen, and how hard/soft those shifts were. Later I worked on transmission cooling across all Ford vehicle lines.
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