I got the tires balanced this weekend still got the problem.

It starts shaking at 40 and stops at around 50 if you let off the gas it stops...

Im going to flush the trans does any one know how many quarts of fluid it takes?

97 F-150 4.2 Liter

 

10-14 qts depending on the transmission pan and if u added a trans cooler, but i would just take it to a quick lube place ,cause you have to take off on of the lines running to the radiator, hook it up to the machine that will suck the old fluid out and put the new fluid back in. cost about $90

 

It turned out to be the drive shaft. I ended up finding one online with 55k on it. Threw it on and she rides like new. Thank god the shaking is over....

 

I went to get smog. They said it passed, but my check engine light brings up codes P0401 & P0402. I 'm wanting to fix this . After reading in this forum, it sounds like i need to replace the DPFE. Is this correct? I have 2001 f150