I have a 94 f150 can't figure out hard shift
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6th Gear
Joined: Mar 2026
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I have a 94 f150 can't figure out hard shift
I have a 94 that was a manual from the factory. The transmission is an automatic. I have replaced the sensor on the rear axle, the computer, the transmission itself, the speedo, the rear brake housing and the bulb, the fluid is great its new too. When I drive I feel a clunk I guess and the vehicle rocks from from front to back. When I put it in drive or any other gear it rocks too. Something just isn't right. Any help appreciated.
Last edited by LiTTleREdz; Mar 5, 2026 at 08:03 AM. Reason: Spelling
Logistics Pro
Joined: Aug 2014
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When parked into drive, or while driving?
Rocks? please explain.
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6th Gear
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Logistics Pro
Joined: Aug 2014
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It sounds like you’re describing a swap or repair involving the Ford E4OD behind a Ford inline-6 (300 I6), and now the truck rocks or jerks when going into Drive/Reverse and during shifts, sometimes with a pop. From what you wrote, a few things stand out.
✅ Things I would check first (in order):
1. Missing or incorrect wiring harness
You mentioned you didn’t get a harness but did install the MLPS (Manual Lever Position Sensor). On an E4OD this matters a lot because the transmission is electronically controlled by the ECM/PCM. If the wiring isn’t correct:- The computer may not know the gear position
- Shift timing and line pressure can be wrong
- It can cause hard engagements or rocking when shifting
2. MLPS alignment
The MLPS must be perfectly aligned in Neutral during installation. If it’s slightly off:- The PCM thinks the truck is in a different gear
- It can cause harsh engagement, popping, or rocking
- The truck may slam into gear
3. Wrong computer (ECM/PCM)
You said the computer guy asked if anything was changed. That’s important because:- E4OD trucks require a PCM programmed for E4OD
- Some 300 I6 trucks originally had the C6 transmission
- If the PCM calibration doesn’t match the transmission, shifts can be wrong.
4. Engine / transmission mounts
The rocking and popping could also be mechanical:- Broken engine mount
- Bad transmission mount
- Loose crossmember
5. Driveline slack
Also check:- U-joints
- Driveshaft play
- Differential backlash
6. Torque converter / line pressure
If the transmission is working but engagement is very hard, it might be:- Line pressure too high
- Wrong EPC control from PCM
- Sticking valve body
✅ Things I would check first (in order):
- Confirm the PCM/ECM number matches a 300 I6 + E4OD truck
- Verify MLPS alignment in Neutral
- Check engine and transmission mounts
- Inspect driveshaft U-joints
- Confirm the E4OD wiring harness is correct
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Lead Driver
Joined: Jan 2019
Posts: 5,076
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From: N.W. Alabama
Do you know if its a MassAir, or Speed Density, truck, do you know how to tell?
If its Speed Density, there's 4-5 ECM's that can work $200-350, range.
I hope you have junkyards near you, you'll need the correct harness(E4OD) for the correct ECM to tell it how to shift.
This is the pin outs E4OD has its own.
Ford Fuel Injection
If its Speed Density, there's 4-5 ECM's that can work $200-350, range.
I hope you have junkyards near you, you'll need the correct harness(E4OD) for the correct ECM to tell it how to shift.
This is the pin outs E4OD has its own.
Ford Fuel Injection
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Thread Starter
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6th Gear
Joined: Mar 2026
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It sounds like you’re describing a swap or repair involving the Ford E4OD behind a Ford inline-6 (300 I6), and now the truck rocks or jerks when going into Drive/Reverse and during shifts, sometimes with a pop. From what you wrote, a few things stand out.
✅ Things I would check first (in order):
1. Missing or incorrect wiring harness
You mentioned you didn’t get a harness but did install the MLPS (Manual Lever Position Sensor). On an E4OD this matters a lot because the transmission is electronically controlled by the ECM/PCM. If the wiring isn’t correct:- The computer may not know the gear position
- Shift timing and line pressure can be wrong
- It can cause hard engagements or rocking when shifting
2. MLPS alignment
The MLPS must be perfectly aligned in Neutral during installation. If it’s slightly off:- The PCM thinks the truck is in a different gear
- It can cause harsh engagement, popping, or rocking
- The truck may slam into gear
3. Wrong computer (ECM/PCM)
You said the computer guy asked if anything was changed. That’s important because:- E4OD trucks require a PCM programmed for E4OD
- Some 300 I6 trucks originally had the C6 transmission
- If the PCM calibration doesn’t match the transmission, shifts can be wrong.
4. Engine / transmission mounts
The rocking and popping could also be mechanical:- Broken engine mount
- Bad transmission mount
- Loose crossmember
5. Driveline slack
Also check:- U-joints
- Driveshaft play
- Differential backlash
6. Torque converter / line pressure
If the transmission is working but engagement is very hard, it might be:- Line pressure too high
- Wrong EPC control from PCM
- Sticking valve body
✅ Things I would check first (in order):
- Confirm the PCM/ECM number matches a 300 I6 + E4OD truck
- Verify MLPS alignment in Neutral
- Check engine and transmission mounts
- Inspect driveshaft U-joints
- Confirm the E4OD wiring harness is correct
Cargo Master
Joined: Mar 2007
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I don't know, but typically, the factory does not change a lot to the wiring of a component. The wiring to the E4OD is probably real similar to all the E4OD's. Sure, the wiring colors may be different, but there is probably just one [maybe two] different switches.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,725
Likes: 2,651
From: SE Florida
The first step to figuring this out is to read the codes. Here is how www.troublecodes.net/ford
Last edited by Mark Kovalsky; May 3, 2026 at 09:03 AM.
Hotshot
Joined: Jul 2020
Posts: 10,478
Likes: 2,636
From: Near Salt Lake City
The first step to figuring this out is to read the codes. Here is how www.troublecodes.net/ford
His lack of a E4OD processor is the problem
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6th Gear
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my computer is for a 4.9l automatic that was changed too
Thread Starter
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6th Gear
Joined: Mar 2026
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Likes: 1
Buy a factory manual. I have one on a CD that I have purchased years ago. I suspect someone still has them.
I don't know, but typically, the factory does not change a lot to the wiring of a component. The wiring to the E4OD is probably real similar to all the E4OD's. Sure, the wiring colors may be different, but there is probably just one [maybe two] different switches.
I don't know, but typically, the factory does not change a lot to the wiring of a component. The wiring to the E4OD is probably real similar to all the E4OD's. Sure, the wiring colors may be different, but there is probably just one [maybe two] different switches.