January 01, 2013

4T65-E Channel Plate Identification

Valve Body Xpress

Valve Body Side
GM StyleVolvo & GM Tap Shift Style
Case Side
Early Style (1 Blow-Off Ball)Late Style (2 Blow Off Balls)

There are two worm track configurations on the valve body side of 4T65-E channel plates: GM Only style & Volvo/GM TAP shift style. There are two possible locations for pressure blow-off balls, along with their associated springs & retainers:

  • The TCC blow-off ball is present on all models.
  • The converter drain-back blow-off ball is only used on some channel plates.

On models with no drain-back ball, the pressure relief valve will instead be located in the return cooler line fitting. It is important not to put a channel plate with a drain-back ball on a unit that did not previously use one, as having both a valve in the return line and one on the channel plate will cause a lube restriction and failure.

Another difference between some early & late channel plates is an additional machined area for the new design 4th clutch that has an additional external tab on the steel plate. This was a running change made mid-year 2002. (BLUE ARROWS)

Part Number Chart

Part NumberChannel Plate Casting NumberYearsStyleBlow-off Balls
GM171 (Warranty Only)24211900'97-'02GMTCC Only*
GM172 (Warranty Only)24224086 or 24229721Mid-'02-LaterGMTCC & Converter Drain-back
GM173 (Warranty Only)24224896Mid-'02-LaterGMTCC Only
GM174 (Warranty Only)24213496'99-'02VolvoTCC & Converter Drain-back
GM175 (Warranty Only)24224897 or 24229720'03-LaterVolvo & GM Tap Shift**TCC & Converter Drain-back

*NOTE: Some 24211900 channel plates have both TCC blow-off ball & cooler drain-back blow-off ball. The TAP Shift & Volvo channel plates have a Lo blow-off valve near the manual valve (see red box above) instead of a drain-back blow-off ball.
**NOTE: Looks like a Volvo on the valve body side and uses a late-Volvo-style valve body with 3-piece pump.

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