In a torque converter, clutch release clearance (CRC) is the distance that the torque converter clutch piston travels from the release to the apply position. This distance is also the amount of free play that is available to the clutch or clutches when the TCC piston is in the release position.
In a transmission, the rules that govern the setting of the CRC are very straightforward. Giving a clutch pack .008” to .009” of clearance for each friction will usually yield good results, although there are a few exceptions. The 4L30- E overdrive clutch – along with a few others – uses a little extra clearance as part of its accumulation action. But in the long run, you’d be fairly safe using the .008” to .009” per friction rule across the board.
In a torque converter, the rules are quite different. Many additional factors beside interference clearance come into play. The in-and-out flow of some converters is affected by CRC and must be considered. TCC apply feel is a factor on some converters. On others, the CRC is restricted because of the amount of available travel (captive clutch) or by a secondary obligation (retaining the springs on an A500 or A518). In units like the 722.6 and RE5R05A, there is an actual clutch pack in the converter, similar to those found in a transmission.
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Article No.: TCIP-01-08
Author: Ed Lee
Total Pages: 2
©2008 Sonnax Industries, Inc.