Help!
I purchased this truck new in September of 1997. Shortly thereafter I began to develop harsh shifting in the automatic transmission when upshifting (usually) from second to third gear. Once you remove your foot from the gas pedal, shifting would occur normally, otherwise the engine would redline. This problem occurred sporadically, but is now more frequent. At 11,000 miles, I took to the dealer, again at 15,000 and again at 48,250. All three times, NO PROBLEM FOUND! No EEC codes present, therefore no fix. No duplication of harsh shifting by service staff, which occurs almost everytime I drive it, now.

The EEC code P1728 was obtained when I drove this truck back from Colorado this summer and decided to stop at a dealership to have the check engine light analyzed (other sensor problems). There it was for the first time! But still, dealers at home cannot duplicate??? I have not changed the transmission fluid or filter as suggested by the owners manual at 30,000 miles, but soon will.

Any thoughts? Thanks for your help.

Bill

 

Hi Bill and welcome to FTE

A P1728 is for excessive clutch slippage in the toque convertor. It usually wont cause the engine to redline before it shifts but anything is possible. I would suspect a bad VSS for that problem.
Before doing anything else I think I'd get the transmission flushed and see what it does with new oil in it.

 

Thanks for the information Racerguy. I must, however, plead ignorance! What is a VSS?

 

VSS is the Vehicle Speed Sensor. It is a small sensor located on the top of the rear end housing or in the back or the transmission or transfer case. It is the signal for the speedo and it tells the truck's PCM how fast you're going and is used for ABS too. If you do a search on here you'll find lots of posts about it.

 

Well, after considering your thoughts on the VSS, I decided to spend the $19.00 and put it on during my lunch hour. Actually took 15 minutes to do. So far, impressed with the results. Not once has the transmission slipped or shifted hard. Very pleased, and thanks a bundle. These forums are very helpful.

 

Good to hear that you got it fixed

 

I have a 1998 Ford F150 4x4 automatic that is flashing the OD light with P1728. I replaced the VSS, checked fuse 23, and flushed the transmission. Still getting the light...? Any thoughts? Thanks in advance.