E40D kickdown not working
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Senior User
Joined: Feb 2010
Posts: 154
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From: Carolinas Region
E40D kickdown not working
I've noticed that from time to time kickdown stops working on my 95 - 4.9 with E40D.
This isnt something that happens all the time or often, but it happens enough that I need to track it down.
When it isn't happening everything seems to work normally, or as close to normal as a truck this old can be.
When it does happen:
When I am on the interstate the truck wont shift from 4th to third or anything lower when I floor the throttle. I can use the OD button or shifter to change gears. When the truck gets to about 75mph it cuts out or shudders, top speed is limited.
When I am in town, the truck shifts from 1st to 2nd to 3rd to 4th really early, again, if I floor it it just follows the same pattern of early shifts and never runs out a gear or downshifts.
I'm thinking that it is an issue with the TPS circuit or maybe VSS, The TPS has been tested - I need to trace the wires to make sure they dont have any issue - is there a common problem area? What pin would it be on the computer? Can the VSS or neutral safety switch effect TPS function?
This isnt something that happens all the time or often, but it happens enough that I need to track it down.
When it isn't happening everything seems to work normally, or as close to normal as a truck this old can be.
When it does happen:
When I am on the interstate the truck wont shift from 4th to third or anything lower when I floor the throttle. I can use the OD button or shifter to change gears. When the truck gets to about 75mph it cuts out or shudders, top speed is limited.
When I am in town, the truck shifts from 1st to 2nd to 3rd to 4th really early, again, if I floor it it just follows the same pattern of early shifts and never runs out a gear or downshifts.
I'm thinking that it is an issue with the TPS circuit or maybe VSS, The TPS has been tested - I need to trace the wires to make sure they dont have any issue - is there a common problem area? What pin would it be on the computer? Can the VSS or neutral safety switch effect TPS function?
The Southernmost Mod
Joined: Dec 2004
Posts: 6,902
Likes: 21
From: Caracas, Venezuela
How many miles does that trans have?, It might just be a tired E4OD losing pressure. Other than what you have done, you can check the MLPS, as it does a lot more than what the name might imply, and maybe consider adding a shift kit.
Thread Starter
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Senior User
Joined: Feb 2010
Posts: 154
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From: Carolinas Region
The trans has 130k on it. I am sure it isnt perfect, but i dont think it is simply losing pressure. When it does this I can shift it in and out of OD with the shifter button, and it comes and goes, sometimes in a 100 mile trip it will stop shifting, then 10 minutes later downshifting is working again.
Postmaster
Joined: Aug 2005
Posts: 4,728
Likes: 8
From: Cleveland, TN
I've noticed that from time to time kickdown stops working on my 95 - 4.9 with E40D.
This isnt something that happens all the time or often, but it happens enough that I need to track it down.
When it isn't happening everything seems to work normally, or as close to normal as a truck this old can be.
When it does happen:
When I am on the interstate the truck wont shift from 4th to third or anything lower when I floor the throttle. I can use the OD button or shifter to change gears. When the truck gets to about 75mph it cuts out or shudders, top speed is limited.
When I am in town, the truck shifts from 1st to 2nd to 3rd to 4th really early, again, if I floor it it just follows the same pattern of early shifts and never runs out a gear or downshifts.
I'm thinking that it is an issue with the TPS circuit or maybe VSS, The TPS has been tested - I need to trace the wires to make sure they dont have any issue - is there a common problem area? What pin would it be on the computer? Can the VSS or neutral safety switch effect TPS function?
This isnt something that happens all the time or often, but it happens enough that I need to track it down.
When it isn't happening everything seems to work normally, or as close to normal as a truck this old can be.
When it does happen:
When I am on the interstate the truck wont shift from 4th to third or anything lower when I floor the throttle. I can use the OD button or shifter to change gears. When the truck gets to about 75mph it cuts out or shudders, top speed is limited.
When I am in town, the truck shifts from 1st to 2nd to 3rd to 4th really early, again, if I floor it it just follows the same pattern of early shifts and never runs out a gear or downshifts.
I'm thinking that it is an issue with the TPS circuit or maybe VSS, The TPS has been tested - I need to trace the wires to make sure they dont have any issue - is there a common problem area? What pin would it be on the computer? Can the VSS or neutral safety switch effect TPS function?
It sounds like you have other issues causing your problem, since the E4OD is COMPLETELY computer controlled any "tune up" issue can and will have an effect on shifting. Pull the DTC codes, and before you say "my check engine light isn't on", let me repeat check for codes, there can be codes set that will cause problems and never turn the light on...
It's cheap and easy, heres how: Fuel Injection Technical Library » How To Run a Self-Test if counting flashes of light is not your thing, you can get an Innova 3145 code reader for about 25 - 30 dollars at most parts stores or Amazon.com.
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Senior User
Joined: Feb 2010
Posts: 154
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From: Carolinas Region
Its pretty important to the solving the problem that this is only an occasional issue that surfaces, most time 98% of the time, I dont have this issue, and the transmission shifts correctly. That is why I am leaning to an electrical issue - just with what parts?!
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Does your speedo operate normally all the time or does it do strange things when the trans misbehaves?
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FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
Just to be clear... you are getting the all clear code 111?
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Thread Starter
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Senior User
Joined: Feb 2010
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From: Carolinas Region
I usually only notice when I am trying(and praying - this is a 4.9 afterall) to pass a big rig in the passing lane, if I get up to 75 and its that time of the month the truck will buck and shudder and I need to complete the pass at 74.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
This isn't related to your trans downshift issues but have you checked fuel pressure? The 4.9 requires upwards of 60psi at low vacuum(WOT) and there should be 45-50psi at idle if I'm not mistaken.
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Senior User
Joined: Feb 2010
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From: Carolinas Region
I'll check those today when I'm off work. I'm slowly going over every system in this truck, when I finally figure it out and having it running right, I usually sell it.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Since there is no TPS code or any other it's time to start metering sensor outputs. I have seen a few TPS failures where the output will not go above 3.0 VDC or anywhere near WOT values. That failure mode will not trigger a code but it will send false throttle position data to the PCM which in turn will not correctly alter injector pulse width, gear selection, etc.