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No Overdrive!

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OSO86

Guest
Tonight while driving home I noticed that the "Up Shift" light flashed on momentarily. I also noticed that my RPM's were a little higher than normal for the speed I was at; (2200rpm @ 65mph), usually I'm at 1500 to 1600 rpms at that speed. After getting off the freeway, I manually shifted through the gears and did not notice any change from 3rd to Overdrive, the rpms stayed the same. Is this problem hydraulic or electrical? The car runs great apart from this problem which developed this night? What am I looking at more or less? ;help It is an '86 w/ 121K.
 

BigRed

Well-known member
Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
Mine did similar to this and heres what I did.

I pulled off the console and disconnected the boot. Then I unsoldered the wires from the little vertical switch on the stick and pulled out the 2 wires (should be black) right to the plug and I cut the wires with suffcient wire left to splice back into the plug.

I then replaced them with (Get this Pheonix Gold speaker wire..BECAUSE it has a INCREDIBLE Flex ability and many threads of Oxygen block wire) I spliced into the plug soldered taped (Didnt have heat shrink I know I know) then resoldered the new wire back to the switch.

After I was done I examined the old wires to find NO WIRE this whole time I was getting in and out of OD through ARCS!. The wires GM used here is pathetic considering how much movement is used through the stick. I then took my BIC lighter and lit the old wires on fire on the pavement just shaking my head to find the "rubber length was like 10 inches long but the broken sliver wires were only 8 inches Long..Go fiqure long story short Works GREAT now.

Also While your in there (If this is the problem) Check out Ken's site on Doug Nash 4+3 Units Its very Informative. It even have year to year specs on the electrics like RPM Kick outs Etc..Also check the piece he has on the (I forget the exact term) Shift sensor? It tells how to reroute it through a jumper that puts you in total control (Im doing it the next time I have my car in the air)
 
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Alan86

Guest
If the Upshift light is not working, try checking the relay for the O/D unit. It's located on the firewall near the power brakes booster.
 

BigRed

Well-known member
Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
Whoops sorry on my 85 there is no Upshift so I mistook the thread for the OD light My bad :upthumbs
 

Top

Well-known member
Joined
Mar 20, 2002
Messages
161
Location
Las Vegas, Nv
Corvette
1986 Convertible Dark Red Metallic
Sounds like the relay has gone south. Part #14078915 from the General. Mine was $18.22 here in Vegas. Good luck :beer
 
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OSO86

Guest
Re: No Overdrive

I forgot to mention that I have an Automatic Trans. I went to the dealer to buy the relay and they told me thatThe automatics don't have relays of any sort. The only thing that comes close is the overdrive solenoid that is located on the transmission itself. I'll just have to take it in and have them give me a diagnosis. Thanks for all the tips and ideas anyway.
 

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