Hard Shifts
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4th Gear
Joined: Jul 2024
Posts: 4
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From: TN
Hard Shifts
Hello all,
2012 F250 6.7 4x4 6r140. My old transmission was getting terrible shift flares and slamming gears pretty hard. Looked at the dipstick and it was coated in metal dust. I just installed a 2012 6r140 from a wrecked truck with 160k on it. I had the batteries disconnected for 72 hours. Everything bolted together fine, drained the old fluid (looked good) and installed Motocraft Mercon LV (16qts). Drove it around today and yesterday, fluid looks good and is in the FULL notch. The issue I’m getting is hard shifts 1-2 and hard downshifts 2-1; 5-4. Issue occurs when hot and cold, with and without tow haul. Manual mode intensifies the issue. Not sure if I need to drive it around until the truck relearns, take it to a dealership and clear out the KAM, or start looking at new solenoids/valve bodies. Any advise would be appreciated!
2012 F250 6.7 4x4 6r140. My old transmission was getting terrible shift flares and slamming gears pretty hard. Looked at the dipstick and it was coated in metal dust. I just installed a 2012 6r140 from a wrecked truck with 160k on it. I had the batteries disconnected for 72 hours. Everything bolted together fine, drained the old fluid (looked good) and installed Motocraft Mercon LV (16qts). Drove it around today and yesterday, fluid looks good and is in the FULL notch. The issue I’m getting is hard shifts 1-2 and hard downshifts 2-1; 5-4. Issue occurs when hot and cold, with and without tow haul. Manual mode intensifies the issue. Not sure if I need to drive it around until the truck relearns, take it to a dealership and clear out the KAM, or start looking at new solenoids/valve bodies. Any advise would be appreciated!
Lead Driver
Joined: Feb 2005
Posts: 7,923
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From: The Great State of Texas
My truck had a very lazy 2 to 3 shift flare and I want to say an emissions recall reflash I had done fixed it. There was some shifting issues with the '11-'12 trucks and this flash fixed the issue. Having said that yours is slamming gears so may want the Ford dealer check version of flash is on your truck to determine if there's a newer flash that can resolve your issue.
Lead Driver
Joined: Feb 2022
Posts: 7,958
Likes: 4,039
Visit your dealer to find out if they have a newer PCM code for the transmission. They may just need to reflash to a newer tune. Whatever you do, don't drive it like that until you can get it reprogrammed, or it will destroy itself. Hard shifting isn't that big an issue, the clutch disks prefer that over a soft engagement, but the hard internals may not like it after a while. A firm shift is preferable, but not a hard downshift. Only an IDS can reflash the PCM with the proper tables, so dealer is your best bet.
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4th Gear
Joined: Jul 2024
Posts: 4
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From: TN
Update: figured out the issue and thought I would post it in case any other penny pinchers try to swap a junkyard trans. Luckily, it looks like my transmission wasn’t damaged driving it back and forth to work the last couple days. Every transmission has a specific valve body solenoid shift schedule. It works like this: the solenoid bands are numbered 1-5 normally high and normally low. The specific solenoid shift schedule is listed on your valve body (pan off to see it) and on the side of the transmission (white sticker prone to wearing off). If you’re replacing your transmission, you need to check the band # of all your solenoids (printed on solenoids) and ensure they’re the same on the new valve body, swap your old solenoids on your new valve body, or get a forscan and install the new shift schedule for the new valve body in the PCM. I dumped my fluid (looked fine), changed my filter, cleaned my old solenoids off, and swapped them in the new valve body. Runs and drives great! Thank you all for the help!
Cargo Master
Joined: Jul 2017
Posts: 2,297
Likes: 553
Update: figured out the issue and thought I would post it in case any other penny pinchers try to swap a junkyard trans. Luckily, it looks like my transmission wasn’t damaged driving it back and forth to work the last couple days. Every transmission has a specific valve body solenoid shift schedule. It works like this: the solenoid bands are numbered 1-5 normally high and normally low. The specific solenoid shift schedule is listed on your valve body (pan off to see it) and on the side of the transmission (white sticker prone to wearing off). If you’re replacing your transmission, you need to check the band # of all your solenoids (printed on solenoids) and ensure they’re the same on the new valve body, swap your old solenoids on your new valve body, or get a forscan and install the new shift schedule for the new valve body in the PCM. I dumped my fluid (looked fine), changed my filter, cleaned my old solenoids off, and swapped them in the new valve body. Runs and drives great! Thank you all for the help!
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samckernan
Clutch, Transmission, Differential, Axle & Transfer Case
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Feb 25, 2004 09:54 AM
