Unbelievable transmission problems
#16
#17
It is the same trailer I have always pulled. What about the brake lights? I have electric brake controllers on both trucks - the trailer brakes work fine on both. The brakes on the trailer are activated by pressing on the brake pedal and turning on the brake lights. If the brake lights (and therefore the trailer brakes) were on, you couldn't pull the trailer with a Kenworth.
#18
Is that what you were referring to?
#19
When I say it runs cool - the water temperature gauge stays in the lower part of its range. I do not have a separate transmission temp gauge - the transmission oil is cooled through a radiator heat exchanger.
#20
No, not quite. I think there is a wiring issue with the trailer causing the PCM to think the brakes are on. This will keep the torque converter from locking, causing the exact symptoms he's seen on BOTH trucks. I don't think the brakes are actually on, I think the computer THINKS the brakes are on.
#21
Everything is well within weight guidelines. Truck weighs 7000 empty, plus 4000 load on gooseneck hitch, or 11000 out of max 12000 GVW. Trailer weighs 6000 empty, plus 16000 tractor or 22000 out of max GVW 24000. I have virtually never seen an F550 on the road - everyone pulls their goosenecks with F350s or even F250s. Kind of ridiculous to get an F550 which after all has the same engine and transmission. It may have different tires and wheels - but no tire or suspension component is loaded beyond its rating, and the trailer has its own separate brakes.
When I say it runs cool - the water temperature gauge stays in the lower part of its range. I do not have a separate transmission temp gauge - the transmission oil is cooled through a radiator heat exchanger.
When I say it runs cool - the water temperature gauge stays in the lower part of its range. I do not have a separate transmission temp gauge - the transmission oil is cooled through a radiator heat exchanger.
Regarding the weight towed, yeah its over what the truck is rated for, but it will do it all day long. Its a weekly routine for mine as well and I have never had issue, but run a manual. If you continue towing with either truck I would highly suggest dropping in a larger or more efficient cooler and a valve body. 22k is no joke for a 7.3, but it will do it all day long without issue. Stopping has always been my #1 concern.
GVW is trailer+ truck to not to exceed 24k... which no one follows, but keep in mind the DOT zealots can pop you if they want...
Curious to see if either truck recovers after they cooled down. I agree with mark on the PCM/brake issue, considering you know have a shutter in the trans since the issue. Has it gone away?
#22
#23
No, not quite. I think there is a wiring issue with the trailer causing the PCM to think the brakes are on. This will keep the torque converter from locking, causing the exact symptoms he's seen on BOTH trucks. I don't think the brakes are actually on, I think the computer THINKS the brakes are on.
#24
They could put almost everybody on the road in jail if they checked recommended GVWs. The Kenworth tractor that pulled the 140,000lb bridge beam into town last week probably had a 73,000 GVW. All that extra weight is supported on trailers and dollies.
My mystification is mostly due to why - right now - I am burning up transmissions with a much lighter load than I have pulled in the past (I have about 9000lb on the trailer now). Someone posted that the PCM might be getting a brake light on signal through the trailer harness and it 'unlocks' the converter - which makes a lot of heat. This could make sense as if there is something wrong in the trailer wiring it could affect both trucks. The electric brakes and brake controllers do seem to work fine on both trucks. How would I check if this signal is getting to the PCM?
I suppose the only way I can check if the 7.3's tranny is bad is to drain and replace the fluid and see how it works. It doesn't look great on the dipstick.
I would love to have manual transmissions and not have to have all of this trouble. Seems very sad that currently there is no option for a manual transmission for a new truck.
My mystification is mostly due to why - right now - I am burning up transmissions with a much lighter load than I have pulled in the past (I have about 9000lb on the trailer now). Someone posted that the PCM might be getting a brake light on signal through the trailer harness and it 'unlocks' the converter - which makes a lot of heat. This could make sense as if there is something wrong in the trailer wiring it could affect both trucks. The electric brakes and brake controllers do seem to work fine on both trucks. How would I check if this signal is getting to the PCM?
I suppose the only way I can check if the 7.3's tranny is bad is to drain and replace the fluid and see how it works. It doesn't look great on the dipstick.
I would love to have manual transmissions and not have to have all of this trouble. Seems very sad that currently there is no option for a manual transmission for a new truck.
#25
They could put almost everybody on the road in jail if they checked recommended GVWs. The Kenworth tractor that pulled the 140,000lb bridge beam into town last week probably had a 73,000 GVW. All that extra weight is supported on trailers and dollies.
My mystification is mostly due to why - right now - I am burning up transmissions with a much lighter load than I have pulled in the past (I have about 9000lb on the trailer now). Someone posted that the PCM might be getting a brake light on signal through the trailer harness and it 'unlocks' the converter - which makes a lot of heat. This could make sense as if there is something wrong in the trailer wiring it could affect both trucks. The electric brakes and brake controllers do seem to work fine on both trucks. How would I check if this signal is getting to the PCM?
I suppose the only way I can check if the 7.3's tranny is bad is to drain and replace the fluid and see how it works. It doesn't look great on the dipstick.
I would love to have manual transmissions and not have to have all of this trouble. Seems very sad that currently there is no option for a manual transmission for a new truck.
My mystification is mostly due to why - right now - I am burning up transmissions with a much lighter load than I have pulled in the past (I have about 9000lb on the trailer now). Someone posted that the PCM might be getting a brake light on signal through the trailer harness and it 'unlocks' the converter - which makes a lot of heat. This could make sense as if there is something wrong in the trailer wiring it could affect both trucks. The electric brakes and brake controllers do seem to work fine on both trucks. How would I check if this signal is getting to the PCM?
I suppose the only way I can check if the 7.3's tranny is bad is to drain and replace the fluid and see how it works. It doesn't look great on the dipstick.
I would love to have manual transmissions and not have to have all of this trouble. Seems very sad that currently there is no option for a manual transmission for a new truck.
#26
It's really easy to see if the torque converter is locked or not. Warm the trans up because the converter won't lock when the fluid is cold. It usually doesn't take very long, especially at this time of year. Even when temps are near freezing it only takes a few minutes of driving.
Get it into overdrive, and step on the pedal a little, enough to rev the engine up but not downshift into 3rd. If the RPMs don't change with the speed, the converter is locked. If the RPMs increase by a few hundred while the speed remains mostly unchanged, the converter is unlocked.
If you're in overdrive, on the throttle, in a warm truck, the converter should never be unlocked.
Also, you're crazy for not having a tranny temp gauge in BOTH trucks.
Get it into overdrive, and step on the pedal a little, enough to rev the engine up but not downshift into 3rd. If the RPMs don't change with the speed, the converter is locked. If the RPMs increase by a few hundred while the speed remains mostly unchanged, the converter is unlocked.
If you're in overdrive, on the throttle, in a warm truck, the converter should never be unlocked.
Also, you're crazy for not having a tranny temp gauge in BOTH trucks.
#27
F450's and 550's have a much bigger brake package, hence the increased towing capacity. If you are towing a 16,000lb tractor with a truck that is rated to tow 12,600lbs (which I believe the 2001 F350 is rated at, either way, it wasn't rated any where near 16,000 plus the trailer), you are asking the brakes to do way more than they were designed to do. Yes the transmission and engine can handle it but to safely be able to stop is the questionable part.
#30
Of course you must have trailer brakes on any trailer over 3000lbs. You're only asking the truck brakes to stop the truck itself. The brakes on my tandem dually trailer are so good I sometimes use them alone for braking or descending hills - must be a throwback to my over-the-road trucking days when you often used just the trailer brakes (someone else maintained the brakes on trailers).