How does an E4OD get its load signal?
Thread Starter
|
Junior User
Joined: Jan 2003
Posts: 91
Likes: 0
How does an E4OD get its load signal?
I know a non electronic auto gets is load signal through the intake vacuum but how does the E4OD do it? I have been having OD problems with mine so I am thinking the trans computer thinks there is more load on the tranny then there actually is.
Thanks,
Dave
Thanks,
Dave
Cargo Master
Joined: Oct 2003
Posts: 2,833
Likes: 4
From: Jefferson, Iowa
usually it judges speed and the amount of throttle you are giving it. This is done through the speedo sensor and the throttle postion sensor. If you speedo is working fine, then usually is it a TPS sensor. Take it to a local autozone or advance auto parts store and have them pull the codes, if any. I would bet its your TPS sensor, unless the tranny is pre-96. The older E4od's had common problems with solonoid packs and torque converter slippage. The torque converter slip or shutter will throw a code and make the tranny shift hard, so i think you are fine there. If i am not mistaken, the solonoid pack will throw a code also. So if no codes, and your speedo is reading correctly, i would say your TPS sensor.
Thread Starter
|
Junior User
Joined: Jan 2003
Posts: 91
Likes: 0
I have a code reader and already tried pulling codes but got nothing. I also went through the TPS diagnostic procedure and it checked out fine. I don't feel any slipping in the TC. The problem occurs at highway speeds. When going uphill the truck will shift from OD to Drive too easily. I have to baby the throttle to keep it in OD. I suspect the MLPS but since there are no codes I don't think I should replace it. The only thing that I can think if is that the tranny fluid is a little high but I really doubt that would cause these symptoms.
I know for sure its acting funny because I drove another truck that is nearly identical, same motor, tranny and rear differential, and that truck does not shift this way. I can put quite a bit of throttle into that truck before it downshifts. Any ideas?
I know for sure its acting funny because I drove another truck that is nearly identical, same motor, tranny and rear differential, and that truck does not shift this way. I can put quite a bit of throttle into that truck before it downshifts. Any ideas?
Cargo Master
Joined: Oct 2003
Posts: 2,833
Likes: 4
From: Jefferson, Iowa
try disconnecting the battery overnight, and see if it still does it. The tranny might act on how it is driven, like shift points and such. So if someone towed a lot with it, or still do, it might downshift easier, this is just a guess, but would not hurt anything.
Post Fiend
Joined: Jun 2001
Posts: 5,228
Likes: 5
From: Running Springs CA
Do you have a tach? My E4OD downshifts at the slightest upgrade also, but I think that is normal with the 5.0 and 3.55 gears. It is turning only about 1800 rpm at 60 in OD and lockup, so the engine is not producing much power. The PCM is looking at engine rpms as well as road speed and throttle position. Depending on model year, it may also be looking at engine vacuum by reading the MAP sensor signal.
Jim
Jim
Thread Starter
|
Junior User
Joined: Jan 2003
Posts: 91
Likes: 0
I will try to unplug the battery overnight and see what happens.
I don't have a tach but I am going to borrow a portable one and hook it up sometime soon. I don't think its normal, maybe it is. Like I said I drove an identical truck (5.0 and 3.55 gears) and it did not downshift nearly as easily. In either case its annoying as all hell! Thanks for the help though.
I don't have a tach but I am going to borrow a portable one and hook it up sometime soon. I don't think its normal, maybe it is. Like I said I drove an identical truck (5.0 and 3.55 gears) and it did not downshift nearly as easily. In either case its annoying as all hell! Thanks for the help though.
Post Fiend
Joined: Jun 2001
Posts: 5,228
Likes: 5
From: Running Springs CA
Annoying is going up the mountain and it is constantly shifting between 2nd and 3rd because road/traffic conditions dictate 35-45mph speeds. The 5.0 and 3.55 gears is a less than ideal combination and yet they built so many of them.
Jim
Jim
