Changing gears with a EOD4
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5th Gear
Joined: Feb 2023
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Changing gears with a EOD4
I'm new to the forum and just don't know anything about Ford transmissions. I have a 93 F150 SWB with a rebuilt and cammed 302 and a rebuilt stock EOD4 trans. Has no power and taking out the 3.08 gears it has and swapping them with 3.73 would help it move better down the road. My question being since the EOD4 trans is electric and bases the odometer on a speed sensor in the trans (I believe), would the odometer need a different gear to make the speedo read mph right or would it just detect the mph fine on the speed sensor?
Thanks in advance.
Thanks in advance.
Logistics Pro
Joined: Nov 2013
Posts: 3,930
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From: Mojave, Ca
The vehicle speed sensor (VSS) is actually perched on top the rear differential. It reads the pulses of the ring gear tone ring. There's no speedometer gear. The VSS sends the signal to the programmable speedometer/odometer module (PSOM) where the signal is conditioned and calibrated. The ECU gets it's speed info from the conditioned PSOM speed signal and sends commands to the transmission.
If your speedometer is way off, it'll affect the shifting of the transmission.
You can reprogram the speedometer to make it accurate if you know what you're doing. You only get 5 shots at it before all the burnable memory in the PSOM is consumed, so make sure you know how it works before reprogramming.
If your speedometer is way off, it'll affect the shifting of the transmission.
You can reprogram the speedometer to make it accurate if you know what you're doing. You only get 5 shots at it before all the burnable memory in the PSOM is consumed, so make sure you know how it works before reprogramming.
Lead Driver
Joined: Oct 2016
Posts: 6,185
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From: Houston/Sugar Land
The Ford E4OD uses a speedometer gear in late 80's and 90 and 91 trucks. Since you said you had a reconditioned E4OD you may very well have the gear. If your 93 is a early model from 92, you might also have the gear since parts in changeover years are sketchy..
You also have 6 times to reprogram the PSOM not 5.
Hope this helps.
You also have 6 times to reprogram the PSOM not 5.
Hope this helps.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
All 1992 and up trucks use the rear axle VSS and a PSOM for the speedometer/odometer.
Changing rear axle gears has no effect on speed/odometer calibration.
I would highly suggest at least 4.10 gears. If you are using taller tires as well then 4.56 is not unreasonable.
What are the specifications on the cam? Very easy to pick the wrong one that moves the power band too far up the scale for use on a heavy truck.
Changing rear axle gears has no effect on speed/odometer calibration.
I would highly suggest at least 4.10 gears. If you are using taller tires as well then 4.56 is not unreasonable.
What are the specifications on the cam? Very easy to pick the wrong one that moves the power band too far up the scale for use on a heavy truck.
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5th Gear
Joined: Feb 2023
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Idk the specs on cam, I was told it a HP cam and not a torque one. So I'm it's just for sound more than anything. The trans just shifts pretty quickly, you can feel it shift every gear by the time you hit 50 mph. Then I turn on the over drive so it runs at about 1700 rpm at 60-70 mph.
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Fleet Owner
Joined: Oct 2005
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From: Kentucky
Changing the rear gears does not require reprogramming the PSOM. Changing tire diameter, yes you do: PSOM Info
This is another method to do accomplish the same thing: Simplified PSOM Calibration using GPS
Again none of this is required for a gear change.
This is another method to do accomplish the same thing: Simplified PSOM Calibration using GPS
Again none of this is required for a gear change.
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Logistics Pro
Joined: Aug 2010
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From: Chillicothe
If you have the run of the mill rumpity cam that doesn't make power until it is revved up high in a 4x4 with tires bigger than 31s you need 4.56s.
Plain and simple, i have been down that road with a 94 f150. If you have stock sized tires or 31s 4.11s at minimum.
As the others said, gear change doesn't mess with the speedo.
As for " you can feel it change every gear by 50." You SHOULD be in 3rd by 50, unless you are full throttle passing someone.
Plain and simple, i have been down that road with a 94 f150. If you have stock sized tires or 31s 4.11s at minimum.
As the others said, gear change doesn't mess with the speedo.
As for " you can feel it change every gear by 50." You SHOULD be in 3rd by 50, unless you are full throttle passing someone.
Hotshot
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Logistics Pro
Joined: Aug 2010
Posts: 3,718
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From: Chillicothe
Yeah i suppose so. I just accelerate with enough throttle most of my vehicles stay out of OD till i let back on the throttle some.
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5th Gear
Joined: Feb 2023
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Oh ok wasn't aware of that. I'm used to chevys where you have to change out speedo gears in the dash to fix the mph on speedo when swapping gears. This truck is only a street cruiser 2wd swb, I'm probably gonna stay with the same tire size even when lowered.
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