kreed Posted October 18, 2018 Share Posted October 18, 2018 My 66 Riviera rolling speedometer has been acting weird lately and today began to rotate in all directions with an associated humming noise in the dash at higher speeds . It rotates between 10 mph and 120 mph when I am going 30 mph . Question is : is it most likely the cable itself ? Or more likely a bad speedometer ? Speedometer cables are cheap so thought I would start there unless someone who has more experience has any ideas. Obviously dash has to come out for replacement and we all know how much fun that is . Thanks KReed ROA 14549 Link to comment Share on other sites More sharing options...
Dales90 Posted October 18, 2018 Share Posted October 18, 2018 Just a guess, but may need graphite lube on cable. Could be binding in housing Link to comment Share on other sites More sharing options...
PWB Posted October 18, 2018 Share Posted October 18, 2018 Does it return to zero when parked? Link to comment Share on other sites More sharing options...
RivNut Posted October 18, 2018 Share Posted October 18, 2018 Ken, The first thing that I would try would be to unscrew the housing at the transmission and pull the cable out of the housing and inspect it for breaks, kinks, or dryness. If it looks okay physically, lube it and reinsert it. See what happens then. Sounds like it binds up then releases a bunch of tension causing the eratic readings. Link to comment Share on other sites More sharing options...
kreed Posted October 18, 2018 Author Share Posted October 18, 2018 Thanks, will give it a try tomorrow and let you know. KReed Link to comment Share on other sites More sharing options...
kreed Posted October 18, 2018 Author Share Posted October 18, 2018 24 minutes ago, PWB said: Does it return to zero when parked? Yes it does return to zero when stopped .KReed Link to comment Share on other sites More sharing options...
PWB Posted October 18, 2018 Share Posted October 18, 2018 (edited) That’s a good indicator the head internals are ok. I would disconnect the conduit at the tranny next and turn the internal cable with a variable speed drill motor to isolate. Edited October 18, 2018 by PWB (see edit history) Link to comment Share on other sites More sharing options...
Turbinator Posted October 18, 2018 Share Posted October 18, 2018 7 hours ago, kreed said: My 66 Riviera rolling speedometer has been acting weird lately and today began to rotate in all directions with an associated humming noise in the dash at higher speeds . It rotates between 10 mph and 120 mph when I am going 30 mph . Question is : is it most likely the cable itself ? Or more likely a bad speedometer ? Speedometer cables are cheap so thought I would start there unless someone who has more experience has any ideas. Obviously dash has to come out for replacement and we all know how much fun that is . Thanks KReed ROA 14549 KEN, put the transmission in reverse so you can get your hand clear to take out the speedometer cable and adapter at the transmission. The transmission linkage can be in your way. Seems simple enough; however, it took a period of time for me to realize it is easier to get the thing out ( adapter ) if the linkage is not in the way of your hand. Just a thought that may be of some use. Link to comment Share on other sites More sharing options...
telriv Posted October 18, 2018 Share Posted October 18, 2018 IF the cable is installed CORRECTLY it CAN'T be pulled out from below. IT HAS to be removed from the head. Once it's removed from the head remove the inner cable. Dis-connect the cable at the trans. IT DOESN'T need to be in reverse as this is a TH400 & NOT a DynaFlow. Spray Brakleen OR Carb. cleaner from the top down until it runs out clean. Install the cable & turn it, remove & spray again to remove ALL debris/old grease. Blow out with air to remove spray. Spray cable with Brakleen/Carb. cleaner & wipe down. Roll up cable in your hand & grease while inserting cable at same time turning while installing. Grease until about 3-4" from end. For grease I like using Kendall Super Blue. Maintains it's consistency & will be the same in 10ys. Tom T. 2 Link to comment Share on other sites More sharing options...
RivNut Posted October 18, 2018 Share Posted October 18, 2018 Attn: everyone. No matter how long you've been toying at this, you learn something new every day. ? 1 Link to comment Share on other sites More sharing options...
Turbinator Posted October 19, 2018 Share Posted October 19, 2018 10 hours ago, RivNut said: Attn: everyone. No matter how long you've been toying at this, you learn something new every day. ? You are correct with the assumption people are willing to remain teachable. Red Riviera Bob 1 Link to comment Share on other sites More sharing options...
kreed Posted October 19, 2018 Author Share Posted October 19, 2018 Today's project ! Don't look forward to dropping the dash . Tom is absolutely right - the cable does not come out from below ? KReed ROA 14549 Link to comment Share on other sites More sharing options...
PWB Posted October 19, 2018 Share Posted October 19, 2018 (edited) 1 hour ago, kreed said: Today's project ! Don't look forward to dropping the dash . Tom is absolutely right - the cable does not come out from below ? KReed ROA 14549 I dropped these pics from the 'net and thought it might help through the entanglement. You might as well replace all the bulbs while your in there. Get the LL (long life) As you know all that has brittle plastic mounted on it. Good luck. Edited October 19, 2018 by PWB (see edit history) Link to comment Share on other sites More sharing options...
kreed Posted October 21, 2018 Author Share Posted October 21, 2018 Dropped the dash and changed the cable.Still doing the same thing - guess its the speedometer . All bulbs changed . Thanks for everyone' s help . KReed ROA 14549 Link to comment Share on other sites More sharing options...
PWB Posted October 22, 2018 Share Posted October 22, 2018 Sorry Mr. Reed. Is the speedo cable socket rounded out? Frustrating that GM speedos are sub-par. Theres a few on ebay for sale but I'd prefer to have my original repaired. On 10/20/2018 at 11:58 PM, kreed said: Dropped the dash and changed the cable.Still doing the same thing - guess its the speedometer . All bulbs changed . Thanks for everyone' s help . KReed ROA 14549 Link to comment Share on other sites More sharing options...
kreed Posted October 22, 2018 Author Share Posted October 22, 2018 I suspect that is the problem since I can definitely hear something " spinning " under the dash at higher speeds . Think I will send it to a repair shop to test for me . Thanks KReed ROA 14549 Link to comment Share on other sites More sharing options...
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