Tach Filter GM 14020025 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**K25alive** · 03-30-2020, 08:11 PM

I see this Tach Filter was offered on CK trucks from 75-81. I have a 76/77 gauge cluster with tach that I want to swap with my non-tach gauge cluster (into a 77 C10). Question is, must I use one of these tach filters? And if so, where is it mounted? Is it mounted to the intake manifold? I do not want to fry the tach, just had it refaced, cleaned and calibrated for a pretty penny.

**hatzie** · 03-30-2020, 10:07 PM

I'm not sure that you need one.
The 1983 wiring diagrams show what's inside the filter. You can build one.

**Factory Guy** · 03-30-2020, 11:09 PM

I would ask your restorer of your gauges if it needs a tach filter, My guess is it doesn't, unless you get "tach noise" I wouldn't worry about installing a filter. I have installed a bunch of tachs over the years and I have never installed a filter on ANY.

75C10 · 04-01-2020, 02:18 AM

Yes I have also installed a handful ( have two right now working on a third) all with no filter . Operated for about twenty years and seems accurate.

03-30-2020, 08:11 PM	#1
K25alive Registered User Join Date: Jun 2015 Location: Portland, OR Posts: 274	Tach Filter GM 14020025 I see this Tach Filter was offered on CK trucks from 75-81. I have a 76/77 gauge cluster with tach that I want to swap with my non-tach gauge cluster (into a 77 C10). Question is, must I use one of these tach filters? And if so, where is it mounted? Is it mounted to the intake manifold? I do not want to fry the tach, just had it refaced, cleaned and calibrated for a pretty penny.

03-30-2020, 10:07 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: Tach Filter GM 14020025 I'm not sure that you need one. The 1983 wiring diagrams show what's inside the filter. You can build one. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

03-30-2020, 11:09 PM	#3
Factory Guy Senior Member Join Date: Jun 2019 Location: Midway USA Kentucky Posts: 566	Re: Tach Filter GM 14020025 I would ask your restorer of your gauges if it needs a tach filter, My guess is it doesn't, unless you get "tach noise" I wouldn't worry about installing a filter. I have installed a bunch of tachs over the years and I have never installed a filter on ANY.

04-01-2020, 02:18 AM	#4
75C10 Registered User Join Date: Oct 2014 Location: Calgary Alberta Posts: 161	Re: Tach Filter GM 14020025 Yes I have also installed a handful ( have two right now working on a third) all with no filter . Operated for about twenty years and seems accurate.



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