Five high-static .098 in. reverse clutch frictions for GM Powerglide and TH350 builds, made to hold reverse under a transbrake or high-stall launch.
If your Powerglide drag car rolls forward on the transbrake, will not hold at the stall speed you built it for, or came apart with a glazed, burnt reverse pack, this is the part you rebuild that circuit with. It is a set of five TCI 724105 Xtreme Performance HD reverse clutch frictions, each .098 in. thick, cataloged by TCI for the GM Powerglide and the TH350. These are the plates that end up doing the hardest work in a transbrake car, and the stock-style paper that came in an overhaul kit was never meant to hold a built engine at the line.
The Powerglide is a two-speed. First gear is held by the low band clamping the drum, and Reverse is made by applying the reverse clutch pack at the back of the case. On the street that pack only works when you back out of the driveway. Add a transbrake valve body and its job changes completely. When you hit the button in low, the brake valve sends line pressure to the reverse piston while the low band is still on, so the unit is trying to go forward and backward at the same time and locks up. You bring the engine up against that lock, let go of the button, reverse exhausts, and the car leaves in low. All of that held torque goes through the reverse frictions, which is why the pack and the friction material matter so much on a race 'Glide.
TCI describes the Xtreme Performance HD friction as a softer, more resilient base paper saturated with phenolic resin and silicate for heat resistance, built for smoother apply and longer life in high horsepower units and easier on the opposing steels. TCI pairs it with its high-static reverse steel plates, sold separately, to stop forward creep on the transbrake.
The Powerglide and the TH350 are fully hydraulic units with no computer, so there are no trouble codes to read. Diagnosis comes from how the car behaves at the line, line pressure readings and what you find in the pan.
Do not assume the plates are the only cause. BTE lists several reasons a Powerglide moves on the brake: staging at too low an RPM for a stock or weak pump to apply reverse quickly, a weak or failing transbrake solenoid, and a damaged reverse piston or seals that leak off apply pressure. Check the solenoid first, air-check the reverse piston, and look at the pressure readings. If the piston holds air and the solenoid is working, the clutch pack itself is worn, too small for the power, or the wrong material. Low line pressure from worn valve body bores or a tired pump shows up the same way, which our valve body testing guide and delayed engagement guide walk through on the TH350 side.
TCI lists part 724105 for the GM Powerglide and the TH350 reverse clutch. Powerglide reverse packs vary a lot between stock cases, aftermarket cases and race builds, so count the frictions in your unit and compare tooth count, outside diameter and thickness against what you remove before you order. If you are building a TH350 low/reverse pack instead, measure the same way. If you are unsure, send us the transmission type and the case or drum you are running and we will check it. For other Turbo 350 parts, see our TH350 parts collection.
If the unit is coming apart anyway, a full gasket and seal set such as the ATP SMS-9 master repair kit keeps the rest of a TH350 build fresh, and a reverse pattern full manual valve body is the usual partner for a TH350 race pack. Our TH350 fluid type and capacity guide covers the refill.
| Part number | TCI 724105 |
| Fitment | GM Powerglide (also listed for TH350) |
| Clutch | Reverse clutch frictions |
| Thickness | .098 in. |
| Friction type | High static |
| Quantity | 5 plates |
| Item weight | 12.8 oz |
TCI catalogs 724105 for GM TH350 and Powerglide reverse clutch use. Because stock and aftermarket reverse packs differ, compare tooth count, diameter and thickness with the frictions you remove before installing.
Five frictions, each .098 in. thick. Steel plates are not included.
They help when the reverse pack is the weak link. Also check the transbrake solenoid, the reverse piston and seals, your staging RPM and the low band adjustment, since any of those can let the car move.
TCI recommends its high-static reverse steel plates for transbrake cars to stop forward creep. Nitrided steels are another common choice for heat and wear resistance.
Yes. Soak them in clean ATF for at least 30 minutes, then set the pack clearance with a feeler gauge before assembly.
