6R80 to 351 Windsor
This page is for those looking to put a 6R80 transmission behind their 351 Windsor. I put the 6R80 in my 1994 4x4 Ford Econoline, which has a 351 Windsor motor. On this page, I share the parts I used and some of the issues that arose during the installation. There are multiple ways of accomplishing this swap. This is the way I chose to do it, though I am not saying it's the best way. Some of the parts and setup may not be pertinent to your application. Take what help you can find here, and good luck with your swap.
Parts Guide
6R80 Transmission
In order to use the transmission adapter from Speed Gems. You will need a 6R80 from 2011 or newer vehicle that was made for a V8. I purchased mine from B&R Wrecking. Ideally, I would have preferred to buy a rebuilt one from a reputable transmission shop, but many of those ran over $5000+. I paid $1200 for mine from the wrecking company and purchased a year of warranty. If you do choose to go with a used transmission. I highly recommend watching this YouTube video and replacing your lead frame and a few other small components while the transmission is out and easy to access.
Transmission Adapter
I purchased my transmission adapter from Speed Gems. The adapter, US Shift controller, starter motor, and backing plate came as a kit.
Issue 1
Their website states that you can use your stock flex plate with this kit, but that was not the case for me. Apparently, Ford used two different styles of flex plates with the 351 Windsor. Click here to watch a YouTube video explaining the difference. For this kit to work, you will need the Flex plate for an AOD transmission. If you have the flex plate made for the E4OD or C6, the adapter spacer will push up against the flex plate before the bell housing seats to the back of the motor (see images below). I tried to purchase the FRA-205 flex plate that is mentioned in the video, but the quality was terrible (see image below). I eventually settled on a Hays flex plate purchased through the Holley website, part #12-030.
This is my original flex plate notice how the spacer nub doesn't pass through the plate.
This is the Hays 12-030 flex plate made for a AOD transmission. You can see how the nub passes through the plate.
This is why I don't recomend the FRA-205 flex plate. I ordered two of these from different places and both were very poor quality. Notice the mig wire still hanging off the weld.
Issue 2
The starter motor mounts into the adapter. Mine was too far away from the ring gear to mesh well. There is no way at the time of this writing to adjust the start motor mesh. I ovaled out the bottom hole and then tapped in a small set screw through the side. This gave me enough adjustment to get the starter to mesh, and the set screw locks it in place so that it can't creep away over time. I have brought this to Speed Gems' attention.
Issue 3
The backing plate that comes with the kit does not fit very well. After the transmission is installed and the inspection cover is added, I found a few locations where foreign material could easily enter the bell housing. I used some scrap metal and patched these locations. I have brought this to Speed Gems' attention.
Issue 4
I have a low-speed rattle that seems to be coming from the bell housing area. It seems to go away at higher RPMs. My gut feeling is that there is an imbalance. It could be the Torque Converter Spacer or the flex plate. If I were to do this again, I would take the spacer and the flex plate to a good machinist and have them verify that everything is in balance. It may also be the used Torque converter. At the moment, this issue is unresolved.
Transfercase
For my transfer case, I went with an Atlas transfer case with a 3:1 gear set from Advanced Adapters. The Atlas is a well-respected heavy-duty transfer case, and Advanced Adapters also makes an adapter to bolt the transfer case to the 6R80 making it an easy setup.
There is a lot more information to share and I will continue to add to the page as I have time.
I am not benefiting from providing this information. I am doing it because I know how much information like this would have helped me and saved me money. If you found this information useful, please consider sending a donation.
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