700R4 Reaction Shell 1982-2013, new and ready to install. Fits the 700R4. Ships fast from the USA.
Your 700R4 or 4L60E starts in 1st, jumps straight to 3rd, never takes overdrive and has no Reverse? That combination points at the reaction sun shell, and this is the heavy duty "The Beast" style shell built to replace it. It is formed from thicker steel than the factory part and heat treated, it interchanges with 42298B, A74624A and NTP-51810B, and it comes with an updated nylon thrust washer. It covers 1982-2013 units in the GM 4-speed overdrive family: 700R4, 4L60, 4L60E, 4L65E, 4L70E and 4L75E.
The reaction shell (also called the sun shell or sun gear drive shell) is the bell-shaped steel drum that sits over the rear of the gear train. Its outer tangs engage the reverse input drum, and its splined hub drives the reaction sun gear. When the 2-4 band squeezes the reverse input drum in 2nd and 4th, the shell is what stops the sun gear so the planetary sets can make those ratios. In Reverse the reverse input clutch spins the drum and the shell turns the sun gear the other way. Every one of those gears loads the same hub splines, so a shell that is a little soft or thin eventually strips there. Stout engines, heavy trailers and hard 1-2 shifts speed that up.
A burnt 2-4 band, a leaking servo or a failed reverse input clutch can produce some of the same complaints. Sun shell failure is one of the three problems we list in our 700R4 common problems and fixes guide, together with the band and clutch causes to rule out first.
Pressure and band checks narrow it down in the vehicle, but the shell is confirmed on the bench. Pull the reverse input drum and shell out together and try to rotate the sun gear in the shell hub. Any free play, splines worn to a shiny ramp, or cracks running out from the hub mean the shell is finished. Look at the tangs where they enter the reverse drum as well; if the drum slots are hammered, that drum needs attention too. Since the shell was carrying band load, check the 2-4 band lining and servo while you are there.
This shell is listed for 1982-2013 700R4, 4L60, 4L60E, 4L65E, 4L70E and 4L75E transmissions. It is designed to work in both the early units that use a thrust washer behind the shell and the later units that use a Torrington bearing. Even so, gear train parts in this family changed several times over thirty years, so compare it to the shell you pull out before you assemble anything. If you are unsure which revision you have, send us the year, the vehicle and the VIN and we will check it. The full list of parts for this family is on our 700R4 parts page, and our 4L60E vs 700R4 interchange guide explains what changed between the cable and electronic versions.
A stripped shell usually means the unit is coming apart anyway, so it is the right time for a 700R4 master rebuild kit. If the front planet shows pitted pinions or worn thrust surfaces, our 700R4 planetary replaces it in the same job.
| Fits | 700R4 1982-2013 |
| Part type | Reaction Shell |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Yes. It is listed for 1982-2013 700R4, 4L60, 4L60E, 4L65E, 4L70E and 4L75E transmissions. Compare it with your old shell before assembly, or send us your year and VIN to check.
It is designed for both the earlier washer-style units and the later Torrington-bearing units. A nylon thrust washer is included for the washer-style setup.
It interchanges with 42298B, A74624A and NTP-51810B, the heavy duty Beast sun shell numbers used in the 700R4 and 4L60 family.
No. It is the reaction shell and thrust washer only. Reuse your sun gear if the splines and teeth are clean, or replace it if they are worn.
Most often no 2nd, no 4th and no Reverse while 1st and 3rd still work, often with steel on the pan magnet. A burnt 2-4 band can look similar, so confirm by checking the shell-to-sun-gear splines on the bench.
Check the sun gear, the 2-4 band and the reverse input drum slots. Most people install the shell as part of a full rebuild with a master kit, since the unit is already apart.
