i have a 2000 F-150 that shifts way too early. By the time I hit 30mph it is in overdrive. Does not slip and has firm but early shifts. I am thinking the speed sensor but does anyone have any thoughts?

 

Its a computer controlled trans, It would be great if you could watch the data stream with a scanner.


If its shifting too early the computer may think that its in 4 low.

 

Any idea on the data scanner? Is it dealer only?
Thanks.

 

Its a must have tool for any shop that works on today's automobiles. Any shop should have one.
Whether they know how to use it and understands what they are looking at is another thing.

 

does it downshift when you floor the truck? the speed sensor also runs your speedo, so if your speedo works, your speed sensor is working. it the low range light on on your dash? any check engine light or the off light on your gear selector flash at all?

 

Floor it it shifts back down. No service engine light and the OD light does not flash. The more it goes on the more I think the ECU needs to be flashed. As I said before the shifts are firm but way too soon. Thanks.

 

Try unhooking the battery for about 1/2 hour to reset the PCM. then drive it so it can relearn to see if it changes any.

 

I had reset the computer previously, but now that I think about it I replaced the shift solenoids and have not reset it since then. I will give that a try again. I will let you know.

 

If you're comparing your truck to the "old days", you might be over-reacting to the newer fuel economy programming. Shifting early generally improves mileage. Does it wind out to ~5000 if you floor it?

 

The tps switch could be causing this, make sure you check it.

 

OK- Found it. I did not give all the history previously because the only reamaing problem was the early shift, but if this helps anyone in the future I wanted to expand for all.
Here's the senerio. When I bought the truck the transmission would shut down. At this point I did notice the early shift. Would be driving along and it would be shifting good (firm but early) and just drop out. Had to shift to 2 to get it to move. No SEL! Reset computer and would drive cold then shut down. No SEL. Also appeared to have a miss. Replaced plugs, ohm'd COP's verified TPS and scanned, no SEL. Drove the next day and got a SEL. "Shift solenoid B". Dropped the pan, removed the pack and ohm'd. Was bad and replaced. Test drive was good, but very early shift. Started getting random SEL "Bank 1 too lean" which I thought was being caused by lugging the engine with the early shift. Cleared and would come back. Still thought I might have a miss but it was not real bad. Last night hooked up scanner and put in M/L mode. "Missfire cylinder 1". Bingo! Figured the COP was opening up when hot so replaced. Started and got "Cylinder 1 missfire" again. I had replaced plugs, did compression test last week so figured it had to be the injector. Got my stethascope and listened to the injector, very weak tick. Unplugged and made no difference but as I was plugging it in I still had the steth on my ears heard a tick and it quit. The connector was fried on the injector which was causing a weak pulse and random miss. Never got an injector code so it must have had enough continuity to pass the test. Not sure if I can get a new connector but bent the ends to make connection. Purrs like a kitten and shifts great. It appears it had early shift due to lean condition but did not log it in the computer.
Thanks for all the input guys.

 

I have the same exact problem, but with an added twist. My 03' F-150 4X4 does the same thing, shifts up to O/D before 30 mph, and I'm also hearing a noise similar to a tapping lifter, but the noise is coming from the transmission bell housing, also a clunking sound from the same place when I start the engine..... any thoughts?

 

Your all messed up in your thinking!
The shifting is controlled by the combination of the TPS throttle angle and the speed of the truck.
The PCM makes the logic decision based these sensor signals for up and down shifting.
The other engine codes have nothing directly to do with shifting.
OD is not enabled before 45 mph road speed on a warmed transmission.
Don't get confused with converter lock-up. It's not the same as OD.
Check these in your owner manual.
When cold, OD is locked out until the fluid temp come up to about 98 degrees.
Sounds like you just have multiple troubles all at the same time and looking at them as just one and the cause of everything you see wrong.
Repair for each trouble until all are addressed.
For example if one cylinder is down on power, you put more throttle on to compensate for the lost power.
This in turn should 'delay' shifting when the TPS is open still farther than normal as a signal for the extra loading.
Same as accelerating harder with more throttle that would delay shifting to a later higher speed.
Good luck.

 

***Coughing from all the dust knocked off this thread***

 

I'm glad you got some dust up your nose!.
Some one else can use the reply today because they replied today.
OK?
Good luck.