4r100 Hard Shifting
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4r100 Hard Shifting
In case someone else runs into this problem...
Symptoms:
1. Truck would occasionally hunt for correct gear.
2. Truck was shifting hard most noticeably on the 1-2 shift when I accelerated to about 3200 - 3500 rpms.
I searched on the forum here and many had similar symptoms and said to replace the VSS or vehicle speed sensor ($20). I did this and it didn't fix the problem.
I finally checked the trans fluid (idling when hot) and it was under the cross hatch pattern. I didn't bother to check the fluid first because I just checked it at the beginning of the summer and it was fine. Based on past experience with other vehicles, I'm surmising the computer increased the line pressure rather than have the truck make a mushy shift due to the ATF being low. Increasing the line pressure therefore caused the rough shift. Once the fluid was topped off, the truck shifts fine once again.
Hope this helps.
Doug
Symptoms:
1. Truck would occasionally hunt for correct gear.
2. Truck was shifting hard most noticeably on the 1-2 shift when I accelerated to about 3200 - 3500 rpms.
I searched on the forum here and many had similar symptoms and said to replace the VSS or vehicle speed sensor ($20). I did this and it didn't fix the problem.
I finally checked the trans fluid (idling when hot) and it was under the cross hatch pattern. I didn't bother to check the fluid first because I just checked it at the beginning of the summer and it was fine. Based on past experience with other vehicles, I'm surmising the computer increased the line pressure rather than have the truck make a mushy shift due to the ATF being low. Increasing the line pressure therefore caused the rough shift. Once the fluid was topped off, the truck shifts fine once again.
Hope this helps.
Doug
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From: Long Island USA
It's unusual that such a small difference in level caused your issues.
I wonder, if the strainer's gasket/seal is leaking, and when the level just goes down slightly, it starts sucking air - but I think that would cause missed/slipping shifts, not harder ones.
Interesting... VERY interesting...
I wonder, if the strainer's gasket/seal is leaking, and when the level just goes down slightly, it starts sucking air - but I think that would cause missed/slipping shifts, not harder ones.
Interesting... VERY interesting...
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Still Broken....
Still Broken....
I drove around last night for over 30 minutes... stop, start, stop, start and honestly the problem was gone. This morning I woke up and took the truck for a ride and it's still doing the 1-2 shift hard. I checked the fluid and it's full and doesn't smell burnt. I also checked under the hood for any cracked hoses or electrical pig tails unplugged. I found nothing.
Any other suggestions how to go about fixing this? Could the filter be somewhat clogged? Clogged feed or return line to the cooler? I'm lost at this point.
Other items I tried thus far:
1. VSS
2. Reset computer
3. Topped off trans fluid
4. Put in 1 pint of Seafoam Trans Tune (solvent used to free up anything sticking in the valve body). I have since only put about 2 miles on it since that and no improvement as of yet.
Thanks again.
Doug
I drove around last night for over 30 minutes... stop, start, stop, start and honestly the problem was gone. This morning I woke up and took the truck for a ride and it's still doing the 1-2 shift hard. I checked the fluid and it's full and doesn't smell burnt. I also checked under the hood for any cracked hoses or electrical pig tails unplugged. I found nothing.
Any other suggestions how to go about fixing this? Could the filter be somewhat clogged? Clogged feed or return line to the cooler? I'm lost at this point.
Other items I tried thus far:
1. VSS
2. Reset computer
3. Topped off trans fluid
4. Put in 1 pint of Seafoam Trans Tune (solvent used to free up anything sticking in the valve body). I have since only put about 2 miles on it since that and no improvement as of yet.
Thanks again.
Doug
Last edited by douglee25; Nov 4, 2007 at 05:33 PM.
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Originally Posted by krewat
Does the OD light blink when it's doing this? If so, get the code(s) read...
Other than that, let's see if anyone else has any ideas.
Other than that, let's see if anyone else has any ideas.
Doug
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Originally Posted by projectSHO89
What year?
Any thoughts?
Doug
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Originally Posted by Mark Kovalsky
Does the OD off light work when you press the button?
Does anyone have experience with this on the 4r100?
Doug
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Originally Posted by teamgsxr
i own a '99 and there is actually an updated calibration from Ford for hard or erratic shifting issues.
Update: I dropped the pan today. The pan was clean with very little if any material in the bottom. I pulled the valve body and pulled every accumulator, spring, piston, etc. Everything looked good. Nothing was broken. I cleaned everything up and reinstalled it. I then replaced the filter and threw it all back together. I took it for a test drive and everything seemed fine for about the first 25 minutes (about 30 stop/starts). I then felt a harsher 1-2 shift at 3200-3500 rpms. I tried reving it out to 4000 rpms and it didn't seem to shift harshly there.
Questions
1. Could the throttle position sensor (TPS) have anything to do with my problem? The harsh shift seems to only occur in the 3200-3500 rpm range.
2. I also found while I was under the truck that it had the Banks Trans Command installed. I purchased this truck in March and I had no idea. Could a bad trans command cause this issue? I don't have a bypass plug so I can't isolate it from the system.
Any other thoughts?
Doug
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Doug-
I have a '99 that I put a Banks Transcommand in a few years back. It worked great for a couple of years, until one day the truck started to shift incredibly hard. I was unloaded and chirping the tires no matter what I did. I pulled over, put the bypass plug in, and that solved the problem.
If think that you can download the Transcommand manual on-line, and you should be able to rewire yourself back to the stock configuration.
Good luck.
Mark
I have a '99 that I put a Banks Transcommand in a few years back. It worked great for a couple of years, until one day the truck started to shift incredibly hard. I was unloaded and chirping the tires no matter what I did. I pulled over, put the bypass plug in, and that solved the problem.
If think that you can download the Transcommand manual on-line, and you should be able to rewire yourself back to the stock configuration.
Good luck.
Mark
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Originally Posted by mptjelgin
Doug-
I have a '99 that I put a Banks Transcommand in a few years back. It worked great for a couple of years, until one day the truck started to shift incredibly hard. I was unloaded and chirping the tires no matter what I did. I pulled over, put the bypass plug in, and that solved the problem.
If think that you can download the Transcommand manual on-line, and you should be able to rewire yourself back to the stock configuration.
Good luck.
Mark
I have a '99 that I put a Banks Transcommand in a few years back. It worked great for a couple of years, until one day the truck started to shift incredibly hard. I was unloaded and chirping the tires no matter what I did. I pulled over, put the bypass plug in, and that solved the problem.
If think that you can download the Transcommand manual on-line, and you should be able to rewire yourself back to the stock configuration.
Good luck.
Mark
I'll give it a try when I'm done traveling for work on Friday.
Doug
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