Question: F350 6.4 autotrans downshift problem

[wi.threebars]

When I am pulling a trailer af 10,000 lbs in tow mode, I am experiencing a downshift problem. When on interstate coming into a off ramp, the drive train shudders like it just shifted though 2 gears. This is with the automatic trans. I can best explain it like being in 5 gears with standard trans, down shifting into 3rd and popping the clutch. It feels like the drive shaft is trying to torque off or bust some u joints. It only does this when pulling a load, and not all the time. I have about 10K+ miles on the truck. Have pulled trailer on two 2K trips and one 600 mile. Only does it when I touch the brake, only intermittently. I talked to the dealer when had 2-3K miles, got a blank look. Just got back from another trip, called the dealer, again no clue. Anyone have this experience and a fix so I can get back to the dealer. When accelerating there is not problem.

I am very happy with the truck. It is a crew cab, long box, doing everything I expected except for the above. I had a 2002 Ford 7.3, never experienced this down shifting issue pulling the same trailer.

Any HELP out there
Wi.Threebars

[atk]

Welcome to SDD....


may just need the tran`s reprogrammed at the dealer....maybe try talking to a diferent dealer.


not to scare you, have talk to couple of guys with 08`s and they both have had tranny problems. one guy is on his third tranny

[mick1955]

wi.threebars - Have you changed your transmission filter? I talked with a guy in Washington state today. His was doing something similar to what your describing. He changed the filter and said it fixed the problem...

[08f350]

my 08 6.4 auto does the same thing except mine does it with no load at all. I've had it do the downshift shutter traveling down the interstate at about 65mph, pull out to pass and it tries to downshift and it jumps, shutters and scares the heck out of ya. It has also down it 3 or 4 times when slowing down for a vehicle turning in front of me. slow down to 10-20 mph and get back on the accelarator and it can't decide what gear it wants to be in. Shifts shutters, shakes and this can't be good on the drivetrain. Sometimes I see a large puff of white smoke when this happens. Most times I've seen this was on long trips with the truck really warmed up.

I'm up to date on all recalls. I've taken it to the dealer and they can't make it do it. Of course they only drive it 10 or 20 miles, not warming it up enough.

They are trying to blame it on the DPF regen burn....saying it will run rough for about 30-40 miles during and after a burn. Now that the dash tells me when it's burning I know that's not the case. My truck regens about every 300 miles. Most of my driving is a 40 mile round trip commute. I've never seen a problem during my commute, even during the regen. Doing the math if the trucks gonna run rough during regen....that's 10% of the time. I didn't spend 50K to buy a truck that's only gonna run right 90% of the time!!

I'm at 24K miles now....going to do a tranny fluid and filter change soon. Hopefully that will help solve the problem. If not....I'm gonna keep hounding the dealer so when it falls out I'll call 'em and tell them "I told ya so"!!

[hdjeff]

Ford has had the re-occurring problem with drivetrain shudder for some years with trans shudder, loaded, unloaded whatever. Most likely its the carrier bearing that need to be shimmed on the driveshaft.

[MURR3061]

I have experienced this problem. It happened to me on my 08 it seemed after I set the cruise and drove about 30 minutes or more. Then I would need to slow or stop, and on re acceleration the truck would do a neutral drop then start shifting right. But extremely hard. The dealer re-flashed the computer and it worked a lot better. Tell the dealer the shifting is screwed up and see if they will reflash it.