Hello, I am new to the forum, although I have owned several F150 trucks. I have gotten good info from here in the past, and I thank you for the help. Here is my current issue:
97 F150 4.6 L , auto tran w/ overdrive, 4X2. 85K Miles

When I am on highway with overdrive on doing 50-55MPH, and I go to accelerate or pass, I hear and feel a bang from underneath when it goes to upshift into higher gear (I believe 4th gear). I have not noticed the problem when I run without the OD on. I noticed while towing or carrying some weight,that it seems to be less prevalent when doing the same as above, although i can still feel it.

I was wondering if it is the tranny or something else in the drive train that may cause this problem ? I will do me best to answer any addtional troubleshooting tips. Thanks for the help.

 

Hello Dailyk,
Your trans only has 4 gears, 4 is OD so you are downshifting into 3rd. Several times when just cruising at 50-55 I have pushed the OD button off without stepping harder on the gas and the tranny bangs into 3rd. Now I always tromp hard on the gas and make it shift smooth or totally let off the gas then push off the OD. It seems that my tranny doesn't like manual downshifting into any gear with part throttle. It may be that whatever controls the rpms and shifting on your tranny is out of adjustment like when I do a bogus manual shift. How's that for a pinpoint diagnosis? The tranny pros will be along to give some real advise, I'm just yacking. Good Luck

 

I think that your truck might have a u-joint that might be giving out. Also if you want good protection for your hard working transmission, i suggest you add a transmission additive called "LUCAS". Go to an auto parts store and read what it does. It will help with any mild internal problems that your transmission might have.

 

Thanks for the tip, I am going to jack it up and look at the u joint situation, and also take a look at Lucas additive to see how I may benefit from it.