Speedometer problems
Thread Starter
Pro
Joined: Apr 2008
Posts: 681
Likes: 11
From: Carson City MI
Speedometer problems
My 81 with cruise (which doesn't work) had a bouncing speedometer. Really bad at 50 on up. I ordered both cables hoping that was the issue. I first replaced the lower and found the connection to the tranny (automatic) was loose and when I pulled it, the cable end was somewhat twisted. I installed the new lower and tightened both down snug. I did not replace the upper as I thought I had found the problem. Now, my speedo does not work at all !!! I am thinking that the plastic gear in the tranny is bad. Is this easily replaced? Does it pull out or screw out? Any advice greatly appreciated.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,113
From: Crossville TN
The plastic gear just pulls out (you may need to use some needle-nosed pliers to get hold of it). See if the squared hole in the gear shaft is worn out/rounded....or if the gear teeth are worn off. Either will cause your problem. Also, there is a 'friction wheel' and some transfer gears inside the cruise control module; if something in there goes bad, you can get similar symptoms. Try this website for into on replacing the speedo gear:
http://www.transmissioncenter.net/sp...nAodwTzIcg#350
http://www.transmissioncenter.net/sp...nAodwTzIcg#350
Thread Starter
Pro
Joined: Apr 2008
Posts: 681
Likes: 11
From: Carson City MI
Speedometer problems
Another question. The lower cable has metalic on one end and plastic on the other. I put the metal one into the transmission and plastic into cruise control. Does that sound correct?
Racer
Joined: May 2007
Posts: 285
Likes: 0
From: Ga.
I also have a problem with my 82 speedometer. I installed a new gear, and housing. The plastic piece gets quite brittle when it 26 years old. It is very hard to get access to it. Anyway got a new gear & housing, questioned GM about the color of the gear that they gave me. I drove about 5 miles with it, and the speed was way off. On the way back home it completely quit working. I will have to take everything apart to fiqure out what happened. I hope it was not the gear, and plastic is floating around in the transmission.
Pro
Joined: Aug 2007
Posts: 707
Likes: 31
From: Pitman NJ
Also, make sure the a cruise control transducer is good. When these wear, it put more and more tension on the lower cable until it fails.
If you don't use your cruise, go for the single cable. That's what my car has now.
If you don't use your cruise, go for the single cable. That's what my car has now.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,113
From: Crossville TN
You needn't worry about plastic pieces in the tranny. While it is possible that some small piece could get through the sump filter and pump, it really shouldn't do any real damage to the tranny. About the worst it could do is plug an orifice hole in the valve body channel plate. If that happens, you will get a very hard shift...or a very late shift....anyway, you'll know it if that happens. Unlikely, though. [If something like that would occur, just drop the pan, remove the whole valve body assembly/channel plate and clean out any plastic you find; then reassemble it.]
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