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**hatzie** · 05-28-2016, 04:16 PM

Looks like your MY6 uses a similar speedometer gear carrier to the NP208 in my 76 & M1008 and some, but not all, TH350 & TH700R4 from that timeframe.
There's an O-Ring round the large part of the housing and a seal around the cable end of the gear. Either one can leak but usually it's the seal inside the threaded end around the gear stem.
http://www.ebay.com/itm/like/1511809...&ul_noapp=true
I believe part #s are as follows
12440382 SEAL, SPEEDO DRIVEN GEAR (the orange seal in your pic)
1361618 OIL SEAL RETAINER, SPEEDO DRIVEN GEAR (C-Clip in your pic)
I believe it's # 326563 SEAL, SPEEDO DRIVEN GEAR SLEEVE (Black o-ring in the gear carrier)

You can find the orange seal online and probably locally.

The GM 43 tooth driven gear is Purple and probably around $25.
More than you want to know about speedo gears in the 73-87 trucks. http://www.73-87.com/7387garage/drivetrain/speedo.htm

05-28-2016, 04:16 PM	#4006
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,920	Re: Restoring Rusty Looks like your MY6 uses a similar speedometer gear carrier to the NP208 in my 76 & M1008 and some, but not all, TH350 & TH700R4 from that timeframe. There's an O-Ring round the large part of the housing and a seal around the cable end of the gear. Either one can leak but usually it's the seal inside the threaded end around the gear stem. http://www.ebay.com/itm/like/1511809...&ul_noapp=true I believe part #s are as follows 12440382 SEAL, SPEEDO DRIVEN GEAR (the orange seal in your pic) 1361618 OIL SEAL RETAINER, SPEEDO DRIVEN GEAR (C-Clip in your pic) I believe it's # 326563 SEAL, SPEEDO DRIVEN GEAR SLEEVE (Black o-ring in the gear carrier) You can find the orange seal online and probably locally. The GM 43 tooth driven gear is Purple and probably around $25. More than you want to know about speedo gears in the 73-87 trucks. http://www.73-87.com/7387garage/drivetrain/speedo.htm __________________ 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. Last edited by hatzie; 05-28-2016 at 04:34 PM.