TCI High Energy 2-4 band for GM 700R4 and 4L60E. Adds holding capacity over a stock band for firmer 1-2 shifts and less flare into 2nd and 4th.
A 4L60E that holds 1st for too long and then lands in 3rd, a truck that only upshifts when you lift off the pedal, or a 1-2 shift that flares and smells burnt on the dipstick: those are the searches that lead to the 2-4 band. This is the TCI High Energy 2nd/4th band, part number 375100, built for the GM 700R4 (TH700-R4) and the 4L60E found in 1993-2013 Silverado and Sierra 1500 pickups, Tahoe, Suburban, Yukon, S10, Blazer, Camaro and Corvette. TCI makes it with more holding capacity than a stock band, so it is the band to use when the truck tows or the engine makes more power than it did from the factory.
The 4L60E has one band, and it does two jobs. When the 2-4 servo applies, the band clamps around the reverse input housing, which is tied to the reaction sun shell, and holds the sun gear still. That stationary sun gives 2nd gear. On the 3-4 shift the band applies a second time while the 3-4 clutch stays on, and the same held sun gives overdrive. Between those, on the 2-3 shift, servo release oil has to let go of the band at the same moment the 3-4 clutch picks up. Sonnax points out that when the release oil is metered poorly, the band and 3-4 clutch overlap or gap, which hurts the 2-3 shift and shortens 3-4 clutch life. So a band problem and a 3-4 problem are often the same story.
Confirm the solenoids are commanding gears normally first; with both shift solenoids on in 1st and both off in 3rd, a unit that jumps 1-3 with good solenoids points to a friction element, and the band is the one shared by 2nd and 4th. Rule out a broken sun shell too: Transmission Digest notes the sun gear can break away from the shell and take out 2nd, 4th and reverse together, which no band will cure. Our 4L60E shift problems diagnosis guide walks through those tests, and the 4L60E common problems guide covers the sun shell and 3-4 failures that share these symptoms.
TCI 375100 is listed for the GM 700R4 / TH700-R4 and the 4L60E. The band position is shared through the 4L60, 4L65E and 4L70E family, but the servo, apply pin and drum vary with year and power level, so check your servo bore and apply pin before you fit it to those units. If you are not sure which servo you have, send us your year and VIN. You can shop the rest of the hard parts on our 4L60E parts page.
For a full teardown, pair this band with a 4L60E master rebuild kit, a fresh 24245624 reverse input clutch housing if the drum is marked, and the 13-piece bushing driver set.
| Part number | TCI 375100 |
| Position | 2nd/4th (2-4) band |
| Fits | GM 700R4 / TH700-R4, 4L60E |
| Type | High Energy performance band |
| Material | Alloy steel band with friction lining |
| Weight | 1 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
TCI lists it for the 700R4 and 4L60E. The band position carries through the 4L65E and 4L70E, but compare your servo and apply pin first, or send us your year and VIN.
TCI builds the High Energy band for more holding capacity than the original, which firms up the 1-2 shift and resists slipping into 2nd and 4th under load or with added power.
No. A failed servo seal, a broken sun shell or a damaged reverse input drum can cause the same loss. Diagnose with the transmission in the vehicle before ordering parts.
Inspect it. If the band surface is scored, glazed or blued from heat, replace the housing, because a damaged surface wears out a new band quickly.
Fill with Dexron VI, soak the band in the same fluid before assembly, and check the level hot in park.
