Chevy P30 TH 400 transmission questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TheVintageRV'er · 01-28-2017, 09:27 PM

I've got a 1986 P30 chassis with an HD TH 400 3 speed auto transmission. The PO cut some wires on some sending units on the tranny. one that has me wondering is a two wire sending unit on the driver side. I believe it may be a pitch sensor but cannot confirm. I'm hooking up several gauges (trans temp, vaccuum, etc. ) and this cut off sending unit has me scratching my head.

I've looked for GM diagrams but with no luck.

**Bob B.** · 01-29-2017, 02:23 AM

Quote:

Originally Posted by TheVintageRV'er

I've got a 1986 P30 chassis with an HD TH 400 3 speed auto transmission. The PO cut some wires on some sending units on the tranny. one that has me wondering is a two wire sending unit on the driver side. I believe it may be a pitch sensor but cannot confirm. I'm hooking up several gauges (trans temp, vaccuum, etc. ) and this cut off sending unit has me scratching my head.

I've looked for GM diagrams but with no luck.

Kickdown? Most TH 400's use a kickdown switch on the accelerator linkage to give you low gear when you floor it. The connector is towards the rear on the left (driver's) side.

sweetk30 · 01-29-2017, 08:19 AM

post up a pic .

th400 should be a single wire on kickdown plug. and factory should be orange wire .

TheVintageRV'er · 01-29-2017, 10:54 AM

Here are a couple of pics of this sending unit. Also untangling the cruise control unit wiring. Thanks for the replies! the first one is the cut wire (black) tied up on top and the second one shows that sender (two prong) coming out of the tranny on the driver side.

sweetk30 · 01-29-2017, 07:50 PM

2nd pic looks like oil pressure sender aftermarket and its in the oil galley plug port above the oil filter on the ENGINE not the tranny .

01-28-2017, 09:27 PM	#1
TheVintageRV'er Registered User Join Date: Jan 2017 Location: Geneva, NY Posts: 2	Chevy P30 TH 400 transmission questions I've got a 1986 P30 chassis with an HD TH 400 3 speed auto transmission. The PO cut some wires on some sending units on the tranny. one that has me wondering is a two wire sending unit on the driver side. I believe it may be a pitch sensor but cannot confirm. I'm hooking up several gauges (trans temp, vaccuum, etc. ) and this cut off sending unit has me scratching my head. I've looked for GM diagrams but with no luck.

01-29-2017, 08:19 AM	#3
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: Chevy P30 TH 400 transmission questions post up a pic . th400 should be a single wire on kickdown plug. and factory should be orange wire . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.

01-29-2017, 10:54 AM	#4
TheVintageRV'er Registered User Join Date: Jan 2017 Location: Geneva, NY Posts: 2	Re: Chevy P30 TH 400 transmission questions Here are a couple of pics of this sending unit. Also untangling the cruise control unit wiring. Thanks for the replies! the first one is the cut wire (black) tied up on top and the second one shows that sender (two prong) coming out of the tranny on the driver side. Attached Images

01-29-2017, 07:50 PM	#5
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: Chevy P30 TH 400 transmission questions 2nd pic looks like oil pressure sender aftermarket and its in the oil galley plug port above the oil filter on the ENGINE not the tranny . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.



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