I have a 1989 ford f150 with an aod transmission in it and it did have a 302 in it and I swapped it out with a 351. After I installed everything I have not been able to get the truck to move when I put it in gear. I take that back it will move very slow in reverse and when you go in drive it goes slow and shakes hard. When I did the swap I changed the computer to a computer that says is for a 351 with an auto transmission. Also the flexplate I am using is the orginal one that come with this 351 since the flexplate is different between a 351 and a 302 because of the counterweight. But the transmission was fine before the swap and now it will barely move. Also when you put it in gear most of the time it dies so you have to give it a little gas while you shift into gear. So I do not know if the change in the flexplate will affect the torque converter or not. Also the fluid is good and has plenty of fluid in it.

 

Conanski is the expert on the AOD trans, hopefully he will see this and give an opinion.
However is the TV cable hooked up and properly adjusted?
Was the computer you got out of a truck with overdrive auto trans or non-overdrive?

 

You need a flexplate for 351W w/AOD transmission. There is a difference between the 351W flexplate for the E4OD and the AOD. Your original flexplate has most likely shoved the torque converter too far into the pump. This has ruined the pump. You need a flexplate from a late 90's Ford Crown Victoria that came with the 351W and AOD transmission.

You need a computer for a 351W with a manual transmission or C6 because the AOD is not computer controlled. Unless you do not mind having the Check Engine Light on all the time because the PCM is not hooked up to the correct transmission.

 

And the whole transmission too unless you're incredibly lucky. Stop right now and pull that flexplate out, the one you need will be stamped "AOD" and have the smaller 28oz counter weight on it.

 

I went with the flexplate that the 351w came with and it is same year truck with c6 transmission. Is that going to throw everything off since the balance of the motor will be off. I thought the 302 and the 351 are not balanced the same. Just wondering if you knew if the torque converter is balanced or not. Also about the computer I bought one from advance for the same year and it said on the listing it was for a automatic transmission. It did not throw any codes when I started it up and let it run and also about the tv cable is adjusted properly and messed with it a few times just for ****s and grins to see if anything changed and nothing got any better.

 

I have never seen a 1989 F150 with a 351W and C6 transmission. I knew the F250/F350 stayed with the C6 until ~1987. I guess there is always a first? That is why I made reference to the E4OD. I know 100% the flex plates are not interchangeable between E4OD and AOD. I am not certain if the same is true for the C6 and AOD.

The other possibility is you did not get the torque converter completely seated into the transmission. When properly seated you need to pull the torque converter forward a little until it seats flush onto the flexplate. The torque converter is not balanced to the engine, it is "neutral".

 

It seems the C6 was common in 1989 in the ford truck with a 351w but it seems the aod was not. I have seen on other posts people have used an aod and flexplate and converter out of a crown vic with a 351w. But seems the c6 flexplate will mess up the converter and the pump so I am going to throw the aod flexplate on it from a crown vic and see that is the problem. The torque converter was seated properly but I went ahead and pulled the transmission out of it.

 

There is only a slight difference in offset between the C6/E4OD flexplate and the AOD/4R70w flexplate but it's enough to push the TC too far back back into the fluid pump and cause damage. Make sure you look for the AOD stamp on the replacement flexplate, it will be somewhere on a flat surface and pretty small but it should be there. The pics below demonstrate the differences in the two flexplates, that is the AOD version on the left and the C6 on the right.

 

I did not run the truck long but I didnt smell anything burn or hear anything break or hear any noises so I hope the transmission is alright still. I am going to tm and get a flexplate for a aod 351w out of a crown victoria from advance auto.