Brand new replacement AODE/4R70/4R75 overdrive piston with Sonnax servo pin installed by a professional transmission technician. This upgrade is a must to ensure longevity to any rebuild. The Sonnax servo pin kit also includes a hardened E-clip to prevent the common breakage of this clip which will cause a no overdrive condition.
In AODE transmissions, common problems are intermediate roller clutch, overdrive band or forward clutch failure, traced to the O.D. servo pin wearing the case bore. The oil circuit which releases or holds the servo off is present as forward clutch oil in 1, 2, 3 ranges. If this release oil leaks through the case, it can cause the O.D. band to drag and/or forward clutches to overheat. If band overheating becomes extensive, it may not hold in 4th gear, which can allow a neutral condition and excessive roller RPM on a re-engagement of 4-2 downshift. Replace the OE servo pin with Sonnax 76833E.
- Pin has two O-rings to positively seal against the piston I.D. and the case bore, eliminating oil circuit leaks, as well as a new, hardened E-clip