2005, F150, 5.4 L, Automatic transmission, Four Wheel Drive. After it has warmed up to operating temp. From a stop in Drive it acts like transmission is slipping, or maybe shifting in and out of gear, on take off, after it is warmed up.

Cold, in Drive, it takes off and shifts fine, until it warms up to operating temperature. Then from a stop, press the accelerator, engine speed goes up as normal, but does not move, then it seems to jump in and out of gear. Once it starts moving at maybe 5mph or so it shifts fine, shifts fine at speed. Until I slow down to below something like 30-40 mph from highway speed, or lower in town for a stop, then it acts as if it is shifting up and down lurching, or like it is shifting in an out of gear.

If I start off in low gear (1st) and manually shift to Drive once it is moving, no problems, shifts fine after that.

Had transmission flushed at a reliable shop, new fluid, which included torque converter, new filter. No metal on magnet, or in pan. They do not work on transmissions, just flush them.

 

-How many miles on the truck?
-Fluid & filter change done as part of trouble shooting (after problem started)?

 

Good questions. I am curious as well.

Darrin

 

Depends what kind of filter was used. I have seen dacron filters implode restricting fluid intake.

Next time it does that shut it off for a few minutes. If the filter is imploding shutting it off relaxes the filter and will work normally.

 

It sounds like the low one-way clutch is slipping. When you shift to manual 1st the low/reverse band applies to help the one-way hold the planetary carrier in first gear and to provide engine braking. Since you said it doesn't slip when shifted into manual 1st then that rules out the forward clutch which is a common failure point with a 4r70w.

 

60DRB, DarrinBC, Stuart; The truck has 140,000 on it, fluid, flush and filter where changed after the problem started, as first line. Not sure which filter was used.


After it warms to operating temp, until it cools back down, killing it does not help.


70f100longbed that sounds bad. Manually shifting to 1st, and take off, once moving can shift to drive, and it shifts fine.


Was hoping maybe the tss or the oss sensor, however no codes showing though.

 

No other answers?

 

If the problem was before the service you can rule out filter.

 

Yup.

It sounds like a pressure loss issue. Pump or valve body maybe? Hard to say from here unfortunately.

D