Computer and rear question.
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From: NJ where fun comes to die
Computer and rear question.
My 97 E series has always been a bit tough to tow with. It is heavy to start with, maybe 14k loaded. It has a 3.73 rear. I found a rear with 4.63 gears I can get for $100.00. It only has about 40k on it. It is the right size and has the springs still on it, and disc brakes. Everything looks good. My question is what happens to the computer? It will still think it has a 3.73. The rear will be turning at a different speed. Can I tell it to change like a speedo gear change? Will it run bad if I don't? Thanks for any help.
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Originally Posted by trike1946
My 97 E series has always been a bit tough to tow with. It is heavy to start with, maybe 14k loaded. It has a 3.73 rear. I found a rear with 4.63 gears I can get for $100.00. It only has about 40k on it. It is the right size and has the springs still on it, and disc brakes. Everything looks good. My question is what happens to the computer? It will still think it has a 3.73. The rear will be turning at a different speed. Can I tell it to change like a speedo gear change? Will it run bad if I don't? Thanks for any help.
Post Fiend
Joined: Apr 2004
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From: Silver Lake Dunes, MI
On the E-series they use a Dana axle so the 3.73 could be. Like Rick said the gears can be changed without affecting the PCM. The speed is taken off the axle speed not drive shaft speed.
Postmaster
Joined: Feb 2004
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From: Levittown
YUP!
97 was the year the sensor was changed to the trans.
Also non PSOM.
The sensor on the rear is only for the ABS.
3.73 was available in gas only.
Dont know if it was a opt in SD (DRW) (D70).
Bill
97 was the year the sensor was changed to the trans.
Also non PSOM.
The sensor on the rear is only for the ABS.
3.73 was available in gas only.
Dont know if it was a opt in SD (DRW) (D70).
Bill
Last edited by MADVAN; Dec 15, 2007 at 05:42 PM.
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Logistics Pro
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From: NJ where fun comes to die
Thanks for the replies.
The door tag says the rear in the truck is a "81". I believe that is a 3.73. The one I looked at is the same physical size in every way. I said the wrong number though. I called the person who owns it and he said it is a 4.56. These are the big 10" rears. It is also a dually. I asked DANA and they said it will fit but they were not sure of the computer problem. Some say the sensor on the rear is for ABS only. Others say different. But my question is this: where ever the sensor is, it will get a different reading when the rear is changed, especially that much. So whether the signal comes from the rear or the side of the trans, something is turning at a different speed. The computer will send signals to the engine based on what comes in. Something needs to be changed as I see it. And if it is the computer, will the 4.56 be within the parameters the computer will recognize? Am I making any sense, or am I in left field? Can the computer actually be changed at all to recognize a different rear? I can't be the only one to ever do this.
The door tag says the rear in the truck is a "81". I believe that is a 3.73. The one I looked at is the same physical size in every way. I said the wrong number though. I called the person who owns it and he said it is a 4.56. These are the big 10" rears. It is also a dually. I asked DANA and they said it will fit but they were not sure of the computer problem. Some say the sensor on the rear is for ABS only. Others say different. But my question is this: where ever the sensor is, it will get a different reading when the rear is changed, especially that much. So whether the signal comes from the rear or the side of the trans, something is turning at a different speed. The computer will send signals to the engine based on what comes in. Something needs to be changed as I see it. And if it is the computer, will the 4.56 be within the parameters the computer will recognize? Am I making any sense, or am I in left field? Can the computer actually be changed at all to recognize a different rear? I can't be the only one to ever do this.
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Logistics Pro
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From: NJ where fun comes to die
MADVAN, where did that come from? If that is so then my truck has a problem. It should pull a house down, but can't.
I looked at
www.drivetrain.com/Fordtrkratio_posidata.html
It said 81 was 3.73
Are F and E series the same numbers?
I looked at
www.drivetrain.com/Fordtrkratio_posidata.html
It said 81 was 3.73
Are F and E series the same numbers?
Postmaster
Joined: Feb 2004
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From: Levittown
Code 81, 4.63 is for 97E-series.
Took it right out of the 97 spec book (E-series).
But you know how this book crap is.
Only one way to be shure.
As you state. You should be able to climb a wall.
Does the van have any kind of top end speed?
Bill
Took it right out of the 97 spec book (E-series).
But you know how this book crap is.
Only one way to be shure.
As you state. You should be able to climb a wall.
Does the van have any kind of top end speed?
Bill
Last edited by MADVAN; Dec 15, 2007 at 08:29 PM.
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Logistics Pro
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From: NJ where fun comes to die
Actually you are right about that part. It seems to have less than my 96 which has a 4.10. But it has the pull of a 3.73. So now I am at a loss. Less top end would be lower gears. Also my fuel mileage is a little less than the 96. But no power. I have had it hooked to a computer at ford and 2 other places. No problems or codes. Fuel pressure is good. So I thought I found out the problem, but what you are saying puts a hole in my theory.
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From: NJ where fun comes to die
The truck only has 88k. The engine runs very well. No smoke. Only normal noise. the turbo is tight. The cat is not clogged. Never has had much boost. Vans are not much on power to start with. It only goes up to about 10 when I am really on it. I'm going to have to go underneath and look for some numbers. We are in the beginning of a slop storm right now, but as soon as it is over I will crawl underneath and look.
I will report back.
Thanks for the help.
I will report back.
Thanks for the help.
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Logistics Pro
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From: NJ where fun comes to die
OK my theory is down the tubes. The numbers on the rear that is in the truck say 4.63. That means the truck really sucks. It has been tested by 3 different shops on their computers with no codes and no problems and no idea what could be wrong. The truck seems to run fine but has no power on the road. With this rear it should pull anything I want to hook up. But it barely gets out of it's own way. It doesn't smoke. It has good fuel pressure. The truck has about 88k on it. I know the vans are de-tuned but this is pretty bad. Besides a sale sign, does anybody have any suggestions?