I've got an 86 F150 302 AOD 4x2.

It was my Grand Pa's truck, and he passed away in 2008. I got the truck a couple weeks ago after basically sitting for 3yrs.

The trans seems to pull good and does great except when you coast down hill or get behind slower traffic (coasting), then when u give it gas, it slips. If you slow down and let it down shift then it does fine again. It doesn't seem to have lock up (O/D). I can't feel it lock up. I can't feel it unlock when I tap the brakes either. But when it slips and I slow to a "down shift" it never tried to shift back up. It seems like it slips when it should be in OD, but if I never coast it never shifts to OD and never slips.

As long as your giving it gas it does fine (still no O/D though), only after a coast does it slip.

I changed the filter / fluid and ran some seafoam cleaner thru, adjusted the TV cable etc, but it still does it. Do I have a torque converter problem or trans problem?

The trans was rebuilt a few yrs before my Grand Pa died, but it never really seemed right (before or after). He said it didn't shift right, but I can't remember if it ever slipped before.

I have an 87 cougar with on AOD, should I swap them out, just swap TC's or is there something else I should look for?

Thanks in advance!

 

You put Seafoam in the transmission? That wasn't a very good idea.

 

It's the sea foam brand, transmission conditioner.