Stop 4T60-E, 4T65-E Case Wear, Band Slippage & Breakage with a Longer Servo Pin

A broken or burnt-up forward band on the GM 4T65-Etransmissionis not an uncommon thing to see during the teardown process. Most rebuilders have seen bulletins and tech articles pointing out common failures with the EPC having intermittent problems with pressure rise causing a slip or chatter on takeoff, which is probably the biggest contributor to forward band failure.

我以前拥有一个'08大奖赛，并在热门时，EPC会挂断并导致间歇性的无压力上升条件。我始终知道，如果我在长驾驶后停放车辆，那么在20分钟的套装后重新进入车辆，并将其反向退出停车位，我需要等待1,001 ... 1,002选择前向频带的驱动器时计数以完全接合。如果我没有给它2秒的计数并踩到气体之前，在它进入驱动器之前，发动机RPM会竞争，前锋乐队会颤抖，然后陷入困境，几乎像一个中立的下降！

What was happening here, was that the TCM was trying to raise pressure as the selector was placed in Drive, but the vehicle was in a neutral state of sorts. Once the malfunctioning EPC solenoid caught up, pressure would be almost maxed out, causing the harshness when the forward band finally engaged, causing the slam into Forward. Slamming into Drive from a neutral state a number of times like that could definitely break a band. Replacing the EPC during overhaul and verifying or repairing the pressure regulator and torque signal bores would handle this concern.

There is one other area that needs attention, though, and that is the forward servo pin length. I am sure that many rebuilders have looked at the band clearance after installing a new band and noticed that it was quite large. To help close this gap, Sonnax now offers an extended length forward band servo pin, Part No.84571-01K., for use in both 4T60-E and 4T65-E applications. Typical servo pin stroke is approximately .400", so the Sonnax servo pin (coming in at approximately .200" longer) will cut this in half, greatly helping to take up the extra band clearance.

Since the bore in the case for the servo pin can wear as well, the Sonnax pin also incorporates two sealing rings to prevent leakage past the servo pin.

寻址压力控制问题和安装新的Sonnax伺服引脚将有助于加快啮合进入驱动器，因为前向伺服器的旅行会完全应用频段。专注于这两个地区将有助于防止客户投诉并重复破损或燃烧的前向乐队问题。

吉姆拨打is a Sonnax technical specialist and a member of the SonnaxTASC力(Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax Industries Inc. technicians.