I know there are several threads on transmission problems, but mine has me especially worried. I have a 1999 F150 with a 4.2 V6 4R70W Automatic Trans.It concerns me because there are several issues that seem to be wrong and I hope I'm not right, maybe some of you more experienced guys can help me since this is my first F150. When I take off from a dead stop with light to normal acceleration,I can feel a slightly harder shift from 1st-2nd, the rest of the shifts are regular.If I accelerate a lil harder, it gives a noticeably harder shift, with the rest regular feeling shifts. Sometimes when I take off really hard, it wont shift until about 40 mph with an extremely hard shift. The same result with kicking it into passing gear. I've heard several scenarios of TPS and VSS, but I feel it will be a rebuild and Hope I'm wrong. Any help will be appreciated!

 

Sometimes one of the springs on the 1-2 accumulator breaks causing a hard shift. I thought I had that problem with my 02 but I didn't. My problem was that I had not returned my trans to the stock setting with the Superchips tuner like I thought. I also noticed that there was an extra spring in that location probably to fix that particular problem on earlier 4R70Ws. But, I'm not a transmission expert like several members on this site. So wait for them to chime in.

 

it is common for the lower 1-2 accumulator spring to break, but that seems to happen more on the 97 and older transmissions and not so much on a 99 trans. Either way I would remove the pan and make sure the filter hasnt fallen out of the valve body. Fresh fluid and new motorcraft filter cant hurt anything.

while the pan is off, remove the 1-2 accumulator cover and see if the spring is broken. wouldnt be a bad idea to replace the accumulator piston while you have it apart.

 

Would changing the 1-2 accumulator spring fix the passing gear issue?

 

Nope.
How long have you had the truck? What if anything do you know about its history? A PO could have modified it.

 

I have had the truck for about 3 months, but it has been parked more than drove because I drive a company truck most of the time for work. The previous owner said that the motor had been replaced/rebuilt, don't know for sure, he seems kind of sketchy now. If that's the case, it almost makes me wonder if it might just be the TPS, but I wanted a little more professional advice before I went to spending money on parts that didn't need replacing

 

hook up a scan tool and check for stored DTCs.

BTW.. there is NO passing gear, there is 1st, 2nd, 3rd and 4th/OD. when you accelerated the transmission down shifts from 4th to 3rd. its common for forced down shifts to be harsh and sometimes clunk.

Ford updated this transmission in 2001 that solved most of those issues

 

I have ran a scan tool but no codes come up

 

The airbag light is on and I did some research, the clock spring seems to have gone bad causing the cruise and the horn not to work as well, I'm thinking this was used as a farm truck because they rigged up an external horn button, weird

 

I had the 1-2 accumulator spring break on my '99 at about 75k miles, resulting in a late, hard 1-2 shift. If you're handy with tools, it's a pretty simple and cheap repair. If not, it's probably not too expensive at a shop.

http://https://www.f150online.com/forums/transmissions/290525-fyi-4r70w-hard-late-1-2-shift-fixed-w-10-spring.html

 

One last question, should just change the springs, or do the sleeve repair kit? I was researching that the piston bore could be damaged causing this too.

 

I rarely see a piston bore that has more than a scratch in it nowadays. But you won't know till you get into it. I would start with the spring.

D

 

A guy walked up and offered me cash so I sold it, Thanks for the help guys

 

Congratulations! Sometimes that is the best way to solve a problem!