|Valve Body Side|
|GM Style||Volvo & GM Tap Shift Style|
|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:
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||Channel Plate Casting Number||Years||Style||Blow-off Balls|
|GM171 (Warranty Only)||24211900||'97-'02||GM||TCC Only*|
|GM172 (Warranty Only)||24224086 or 24229721||Mid-'02-Later||GM||TCC & Converter Drain-back|
|GM173 (Warranty Only)||24224896||Mid-'02-Later||GM||TCC Only|
|GM174 (Warranty Only)||24213496||'99-'02||Volvo||TCC & Converter Drain-back|
|GM175 (Warranty Only)||24224897 or 24229720||'03-Later||Volvo & 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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