Subject: Improved Vacuum Modulator
Model and Year: 1963 Aluminum Powerglide
Source: Chevrolet Technical Service Bulletin
Bulletin No: DR #568
Section: VII
Date: December 17, 1962
TO: ALL CHEVROLET DEALERS
An improved vacuum modulator system has been incorporated in the 1963 Aluminum Powerglide transmission effective at start of production at Cleveland and beginning with transmission code #T911 at Toldeo. Modulator parts are not interchangeable between old and new design. If service is required, replace parts must be same type as original equipment.
The old and new vacuum modulator systems are illustrated on the reverse side. Parts data is also included to enable the correct parts to be obtained in the event replacement is required.
| ALL 1962 AND EARLY 1963 TOLEDO TRANSMISSIONS |
ALL 1963 CLEVELAND AND 1963 TOLEDO DATE STAMPED T911 AND LATER |
DESCRIPTION |
| 3789122 | 3830276 | Vacuum Modulator Valve |
| --- | 3830311 | Vacuum Modulator Valve Plunger |
| 3812741 | 3830229 | Vacuum Modulator Assem. |
Article ID: 957
Created: October 13, 2014
Last Updated: October 13, 2014
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article/1963-corvette-service-bulletin-improved-vacuum-modulator-957.html