Schwitzer fan clutch rebuild

[Joe L.]

Re: Schwitzer fan clutch rebuild

Interesting point about GM460742 being used on some 1972-79 Corvettes. Is there any information as to break point or other traceable information on when/why this part number was used in 1972? My '72 AIM calls for a different number than 460742.

Don------


I should have said "SERVICE REPLACEMENT FOR" rather than "WAS USED" with respect to 1972-76 Corvettes. The GM #460742 was originally used for some 1977-79 Corvettes and became the SERVICE replacement for 72-76

[Don L.]

Re: Schwitzer fan clutch rebuild

Don------


I should have said "SERVICE REPLACEMENT FOR" rather than "WAS USED" with respect to 1972-76 Corvettes. The GM #460742 was originally used for some 1977-79 Corvettes and became the SERVICE replacement for 72-76

Thanks Joe. Do you know what the differences are between SERVICE REPLACEMENT GM460742 and OE GM3991426?

Since 460742 is a service part, I assume all the performance issues are the same and that all the bolt pattern dimensions match.

[Joe L.]

Re: Schwitzer fan clutch rebuild

Thanks Joe. Do you know what the differences are between SERVICE REPLACEMENT GM460742 and OE GM3991426?

Since 460742 is a service part, I assume all the performance issues are the same and that all the bolt pattern dimensions match.

Don-----


The GM #3991426 and GM #460742 have completely different configurations. Among other things, the 3991426 is a Sweitzer-manufactured clutch with a "bi-metallic" plate type thermostat. The 460742 is an Eaton-manufactured clutch with a "coil spring" type thermostat. The forward-facing side of the 3991426 is very similar in configuration to the GM #3937771 used for some 1968-70 Corvette applications with a "pie-pan-like" outer perimeter configuration.

The history of the 3991426 is very "convoluted". It was used in PRODUCTION from 1971 until mid 1974. It was also specified in SERVICE during that period. However, it was later cataloged in SERVICE only for the 1971 Corvette application with the GM #343720 specified for most 1972-74 applications. The 343720 was the PRODUCTION clutch for most L1974 to L1977 Corvettes. The 343720 was replaced for PRODUCTION in late 1977 by the 460742. The 343720 was replaced for SERVICE by the 460742 in November, 1978.

Although it was not carried in Corvette P&A catalogs after 1973, the 3991426 remained available and re-appeared in Corvette P&A catalogs in 1979 but only for the 1971 Corvette application. It continued to be available until October, 1984 when it was replaced by the GM #14063640 which was discontinued without supercession in March, 1988.

I am 100% confident that the 460742 will SERVICE most 1971-79 Corvette applications except those with HD cooling systems.