Seven-solenoid set for the 1999-2005 Allison 1000 5-speed behind the 6.6L Duramax: shift C, D, E, pressure control G, TCC and trim A and B.
If your Duramax Silverado or Sierra HD with the five-speed Allison 1000 is flaring on the 2-3 or 4-5 shift, banging into gear, or dropping into limp mode on a long pull, the seven solenoids bolted to the valve body are one of the first things a shop checks. This kit replaces every one of them in one pan-drop: shift solenoids C, D and E, the G solenoid, the torque converter clutch solenoid and both trim solenoids, cross-referenced to 29536833, 29533074 and 29533075 (8683167 and D116420A interchange).
The five-speed Allison does not use a simple on/off solenoid per gear. The TCM switches shift solenoids C, D and E to stroke the shift valves that route oil to the clutch packs, then uses the two trim solenoids to control how fast that oil arrives. Trim A and trim B work as a pair: on each shift one controls the apply of the oncoming clutch while the other controls the release of the offgoing clutch, and they trade roles from shift to shift. That is why a weak trim solenoid shows up as a flare on one specific shift rather than a missing gear. The sixth solenoid is the F trim, or TCC, solenoid that applies converter lockup, and on 2004-2005 units the seventh, solenoid G, sits in its own small housing and lowers line pressure at idle and light-throttle cruise.
In this kit the parts are easy to sort by connector color: four white-connector solenoids (shift C, D, E and pressure control G, 29536833), one gray-connector TCC solenoid, and two black-connector trims, trim A (29533074) and trim B (29533075).
Bench-check the old parts with an ohmmeter once the pan is down. Sonnax lists the five-speed specs as 5.5-6.5 ohms for trim A and B, 22-24.5 ohms for shift solenoids C, D and E and for G, and 10.5-11.5 ohms for the F trim/TCC solenoid. A reading well outside those ranges confirms a bad coil. Normal resistance does not clear a solenoid that sticks or leaks, though, and a sticking E-shift valve throws P0872 and failsafe on its own without any solenoid fault. Our Allison 1000 valve body testing guide walks through separating the two, and the limp mode guide covers the wiring, TCM and speed sensor faults worth ruling out first.
This set is for the five-speed Allison 1000/2000 only. The listing covers the 1999-2005 range; in Chevrolet Silverado and GMC Sierra HD pickups the Allison arrived with the 6.6L Duramax for 2001. The 2001-2003 valve body runs six solenoids and has no G solenoid, so on those trucks the G solenoid in this kit is simply not used. The 2004-2005 valve body adds the G housing and uses all seven. The 2006-up six-speed uses a different TCC solenoid with a red connector and different PCS solenoids, so it will not take this kit. Match the connector colors and the numbers on your old solenoids, or send your year and VIN and we will confirm before it ships. Every other part we carry for this unit is in the Allison transmission parts collection.
Drain and drop the pan, remove the filter, and unplug each solenoid from the internal harness before unbolting the retainers. Inspect the harness at every connector; a heat-cracked one throws the same codes as a failed solenoid, so replace it with an internal wire harness while you are in there if the insulation is brittle. Lube the new O-rings with clean ATF, put each solenoid back in its own bore by connector color, and latch every connector fully. Finish with a fresh filter and pan gasket kit, refill with an Allison-approved TES 295 or TES 668 fluid, clear codes, and drive the truck through repeated light and moderate throttle shifts so the TCM can relearn its adaptives.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
29533075 is trim B, one of the two black-connector trim solenoids. Trim A is 29533074. The four white-connector solenoids (shift C, D, E and G) carry 29536833, and the TCC solenoid has a gray connector.
Yes. The 2001-2003 five-speed valve body uses the same trim, shift and TCC solenoids but has no G solenoid housing, so the G solenoid in this kit is left over. 2004-2005 trucks use all seven.
No. The 2006-up six-speed uses a red-connector TCC solenoid and different PCS solenoids, and 2010-up units were redesigned again. This kit is five-speed only.
Sonnax lists 5.5-6.5 ohms for trim A and B, 22-24.5 ohms for shift C, D, E and G, and 10.5-11.5 ohms for the F trim/TCC solenoid on the five-speed.
An Allison-approved fluid. TES 668 is Allison's current recommended spec and is backward compatible with the TES 295 fluids like TranSynd these trucks have long used.
Yes. Clear codes, then drive through normal light and moderate throttle shifts so the TCM rebuilds its shift adaptives around the new solenoids.
