Expands the solid Teflon sealing rings onto the Ford 10R80 CDF drum, then resizes them back down so the drum slides into its bore without shaving a ring.
If you are rebuilding a Ford 10R80 out of an F-150, Expedition, Navigator, Mustang, Ranger or Explorer, the CDF drum is the part most likely to have sent it to the bench, and it is also where a careful rebuild most often goes wrong. The solid sealing rings in the CDF drum positions have no cut joint, so they cannot be spread by hand and snapped into a groove like an old-style scarf-cut ring. This two-piece set gives you the expander to get each ring on and the compression resizer to bring it back to size, so the drum slides home without damage.
The C, D and F clutches share one cylinder in the 10R80, and their apply oil reaches that drum through the input shaft, the No. 3 sun gear shaft and a pressed-in sleeve. Every one of those crossings depends on Teflon sealing rings holding pressure. The expander is a tapered sleeve that stretches a solid ring just enough to walk it over the drum and drop it into its groove. The compression resizer then squeezes the stretched ring back down to bore diameter. Its body has open windows, so you can see that the ring is lying flat in the groove all the way around before you assemble.
If the transmission is apart for a CDF drum replacement under Ford TSB 24-2304, or you are fitting new solid rings to the original drum, you need a way to size them. If the shop that built your unit reports shredded Teflon in the pan after a recent rebuild, a ring that was not resized is a likely cause. Our 10R80 common problems guide explains why the CDF drum fails and how it is diagnosed, and the 3-4 clutch failure guide covers the clutches this drum applies.
The set is sized for the CDF drum ring positions on 2017 and later Ford 10R80 transmissions, the unit used in the F-150, Expedition, Navigator, Mustang, Ranger, Explorer and Transit. It does not cover the input shaft rings or the other 10R80 ring locations, which use different diameters; for those, add the 5-piece input shaft ring resizer kit. Because GM's 10L80 and 10L90 share architecture with the Ford unit but not every part, do not assume these sizes carry over without checking. Browse the rest of our 10R80 parts and tools for the parts that go in with it.
| Transmission | Ford 10R80 (2017-up) |
| Location | CDF drum solid sealing rings |
| Includes | 1 ring expander, 1 compression resizer (2 pieces) |
| Brand | Bonbo |
| Does not cover | Input shaft and other 10R80 ring positions |
No. It is sized for the CDF drum ring positions only. The input shaft and other 10R80 ring locations use different diameters and need their own resizer kit.
Solid rings have no cut joint. Once stretched over the drum they stay oversized, so without a resizer they stand proud of the groove and get sheared by the bore during assembly.
2017 and later F-150, 2018 and later Expedition, Navigator and Mustang, 2019 and later Ranger, plus Explorer and Transit models with the 10R80. The Bronco uses the 10R60, which is a different transmission.
New sealing rings, the C, D and F clutch plates and seals, and the filter at minimum. If the drum sleeve has moved, replace the drum with the updated design rather than reusing it.
Yes. After refilling with Mercon ULV and checking the level hot, clear keep alive memory and run the adaptive learning drive cycle so the TCM recalibrates clutch apply to the fresh parts.
