Magoo
Blind Brain Surgeon
Ok. Narrowing down the mileage problem I have reported before. The truck runs down the road at 55mph and 2000rpm. I have counted the shifts many times and I get 4. Yesterday i hooked up the trailer, which weighs 1500 to 2000lbs and right out the driveway she shifts up quicker than normal and third and fourth are power robbers and damed if I wasnt rolling along at 65mph at 2000rpm. Started racking my brain all day on it. After driving an hour or so it started bucking. Shifting in and out of gear. I believe I know whats going on but not sure why or how to fix. I think, that unloaded it is not fully locking up in 4th gear. (does it also fully lock up in 3rd with the OD button on as well?) With a load the trans is fully locking up. And its locking up in both 3rd and 4th gear. Once fully up to temp on a long pull with a load it bounces in and out of full lock up. Now once I loaded the trailer (8000lbs. of doug fir beams) there was no way to drive it with the OD button on. With the button off it drove fine but it sure sucked the fuel. Roughly 8 to 10mpg. And She cruised 45mph at 2000 rpm. So--------------------
What controls the lock up?
These trannies have throttle position sensors and speed sensors which control shift points. Some say the Tach sensor as well but I am not sure thats true. Which is responcible for lock up?
Where is the computer?
Is it in the trans on the valve body or is it under the dash or something.
So in summary. Truck gets horrible mileage but runs great with out a load. Add a load and my shifting changes and my cruising speed increases with lower RPMs, but it bounces in and out of lock up which sucks to drive.
If it can be fixed I will fix it. If not, than its prolly getting parted out and I am buying another with a 5 speed. Already got my eye on one.
What controls the lock up?
These trannies have throttle position sensors and speed sensors which control shift points. Some say the Tach sensor as well but I am not sure thats true. Which is responcible for lock up?
Where is the computer?
Is it in the trans on the valve body or is it under the dash or something.
So in summary. Truck gets horrible mileage but runs great with out a load. Add a load and my shifting changes and my cruising speed increases with lower RPMs, but it bounces in and out of lock up which sucks to drive.
If it can be fixed I will fix it. If not, than its prolly getting parted out and I am buying another with a 5 speed. Already got my eye on one.