First off I am sorry to say as a mechanic I am probaly a better butcher but I am trying here......

my truck 1999 ford f 150 xlt 4.2 L V6....current mileage is @ 131000 miles
as I take off from a stop shifter in o/d as always starts out just fine then
it is like I put it in neutral at about 40 mph, i look at my shifter and everything seems fine .. i slow down and accelerate again up to 40 mph where my transmission seems to not engage in o/d... i turned the o/d off and headed home.... everything seems fine as long as the o/d is turnned off when i turn the overdrive off it is driveable 1st 2nd 3rd

Drove my truck today to see about getting it checked out...since $$$$ are real tight and limmited right now I had a friend check out the truck today....we changed the Tranny filter, gasket and fluid... he hooked up to his tester and we received the following code...

" p1728 transmission slip error centrifugal clutch fault"
However he could not tell me what the code meant
anyone have an Idea what this means

truck drove fine as long as I had the overdrive turned off although the rpm were high @ 40 mph I was running about 2800 rpm...
I took back roads today so as not to go over 45mph as I do not want to cause any further problems.
Not sure if that was even a good idea but I MISS and NEED my truck and would really love to get it fixed asap.... $$$$ are my biggest issiue at this poing...I have saved up about $500.00 and hope it can be fixed for less then that. any help would be great....thanks to all for helping.


Missing my F 150
Greg

 

The reason it shifts into neutral during the 3-4 shift is because there is a problem with the overdrive band. During the 3-4 shift the forward drum is released and the overdrive band comes on, so if the band cant hold then it feels like neutral because the forward clutch let go.

There could be a couple of different reasons why the band don't hold, one it just could be broken or burnt or there could be a problem with the servo that apply it. If the band is burnt or broke the transmission will have to be rebuilt to fix, the servo could be repaired in the truck but the valve body will have to be removed and the servo inspected. I see both problems in my shop, I say you have a 50-50 chance.

Here is link to a post that shows the servo problem, I must also say that I see the servo e clip problem more in the 03 and up trucks, but its not to say it cant be the same in your case.

https://www.ford-trucks.com/forums/9...ml#post9206889