Side-grip ratchet floor shifter kit replacing part 81120, with cable, cover, brackets and neutral safety switches for the 4L60E and other 3 and 4 speed automatics.
A worn console shifter that will not line up with the gear, a column-shift truck being converted to a floor stick, or a drag build that needs one click per gear are the usual reasons people search for an 81120 replacement. This kit is a side-grip positive ratchet floor shifter for the 4L60E, 4L65E, 700R4 and the other common three- and four-speed automatics, and it comes with the cable, cover, brackets and neutral safety switches in the box so you are not ordering parts after it arrives.
The handle has grips on the side rather than a trigger or a push button on top. Squeezing them releases the lockout so you can push forward toward Reverse and Park, while pulling back from Drive ratchets down one range at a time. On a 4L60E that means Overdrive to 3 to 2 to 1 with a hard stop at each one. The shifter only moves the manual valve through the selector shaft on the left side of the case, so in Overdrive the computer still controls the shifts and the converter clutch. The original 81120 instruction sheet describes the same full-ratchet layout, a reverse lockout that works with one hand, and support for both standard and reverse-pattern valve bodies.
The kit can be set up for two, three or four forward positions. For a GM four-speed like the 4L60E you remove the three-speed limiter blocker pin and e-clips. Ford and Chrysler units also get a Park limiter pin, because those transmissions have less travel between Reverse and Park than GM, and the limiter stops the shifter from stretching the cable.
Harsh engagements, no 3rd and 4th from a stripped sun shell, or TCC slip with P0741 are internal 4L60E faults. A shifter will not touch those.
Pop the old cable off the selector lever and run the lever through its range by hand with the engine off. Each position should click in cleanly. If the transmission behaves with the lever moved by hand, the old shifter or cable is your fault. If it still shifts wrong, start with our Silverado 1500 4L60E shift problems guide, which walks through solenoid states and pressure checks.
Listed fitment covers GM TH200, TH250, TH350, TH400, 2004R, 700R4, 4L60E and 4L65E; Ford C4, C5, C6 and AOD; and 1966-and-later Chrysler A727 (36RH/37RH), A518 (46RH/46RE), A618 (47RH/47RE/48RE), A904 (30RH), A999 (32RH) and A500 (40RH/42RH/40RE/42RE/44RE). A 4L60E or 4L65E with a PRNDL switch needs installation kit 75498, which matches the original 81120 sheet. Without that switch, the supplied GM bracket is used. A 4L85E with PRNDL switch needs bracket 70499, AOD needs 40496, AODE or 4R70W needs 40504, and E4OD or 4R100 needs 40505. None of those adapter kits are included. When in doubt, send us the year and VIN. Everything else for this transmission is on our 4L60E parts page.
If the factory range switch on the case is part of your problem, pair the install with a new 4L60E range switch. Prefer a top-button handle instead of side grips? Look at the 80842-style ratchet shifter.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The shifter body, side-grip handle, shift cable, top cover, mounting and cable brackets, neutral safety micro switches, wiring terminals, shift-pattern decals and bolt and washer hardware. Adapter kits for PRNDL-switch GM cases and Ford units are separate.
Installation kit 75498. Without the PRNDL switch, use the GM bracket in the kit. If you are not sure which case you have, send us the year and VIN.
The original 81120 instructions state the shifter works with both standard and reverse-pattern valve bodies. Set the limiter pins for the number of forward gears your transmission has.
The original design uses a five-foot cable routed from the floor to a bracket on the transmission pan. Route it without sharp bends and clamp it away from the exhaust.
It is recommended. You will drill the floor, set the cable in Low and Park and adjust the neutral safety switch. A mistake that leaves the manual valve short of Park can let the vehicle roll.
