And now speedo problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Skunksmash · 05-27-2014, 03:15 AM

Well now I'm having some kind of speedometer problems. The transmission is a 700R4. 87 5.7L truck, 2WD.

The speedometer isn't working. I recently replaced the speedo gear, that cover that houses the gear, the speedometer cable, and even the speedometer itself. Because I was having a weird tranny leak, and I accidentally broke the old speedometer.

So I hooked up a drill to the cable, and apparently the drill spins at 23mph. So that leads me to believe that its not the cable, and its not the speedometer. That leaves only the gear. But what could be the problem with the gear? I even put the old gear back in and it didn't work either. The only thing I can think of, is if somehow, the cable is not going into the gear. Or, somehow, the plastic speedo gear is not making contact with the metal gear inside the transmission, that turns it. Is this possible? If so, how can you correct this? You can't see inside the transmission once you have everything put back together.

rich weyand · 05-27-2014, 03:30 AM

Make sure the speedo cable housing is firmly clipped into the back of the speedo. It clicks TWICE going in, or at least mine does. I didn't get it in all the way last time, and: no speedometer. Not having it in all the way gives enough slop for the speedo cable (which is helical-wound, so, when turned, it will run up against one end) to pull out on the other end. When you put the drill on it, you may have pushed the cable in so it engaged, then when you mount it to the transmission it walks out. So even if you didn't mess with the speedometer end of the cable this time, make sure that it is clipped in all the way on the back of the speedometer.

Skunksmash · 05-27-2014, 06:03 PM

Thanks I'll give that a try. And report back what happens.

Skunksmash · 05-28-2014, 04:01 AM

You were right, it wasn't clicked in all the way.

However, the needle is a little..erratic. I would say that its accurate, but its not smooth. The needle sort of jumps around a bit. Say you're going 30mph.

The needle will bounce between 29, 30, and 31 mph. Before it didn't really do that. Is this something that might straighten itself out?

05-27-2014, 03:15 AM	#1
Skunksmash Registered User Join Date: Sep 2012 Location: TX Posts: 1,014	And now speedo problems Well now I'm having some kind of speedometer problems. The transmission is a 700R4. 87 5.7L truck, 2WD. The speedometer isn't working. I recently replaced the speedo gear, that cover that houses the gear, the speedometer cable, and even the speedometer itself. Because I was having a weird tranny leak, and I accidentally broke the old speedometer. So I hooked up a drill to the cable, and apparently the drill spins at 23mph. So that leads me to believe that its not the cable, and its not the speedometer. That leaves only the gear. But what could be the problem with the gear? I even put the old gear back in and it didn't work either. The only thing I can think of, is if somehow, the cable is not going into the gear. Or, somehow, the plastic speedo gear is not making contact with the metal gear inside the transmission, that turns it. Is this possible? If so, how can you correct this? You can't see inside the transmission once you have everything put back together.

05-27-2014, 03:30 AM	#2
rich weyand Registered User Join Date: Apr 2014 Location: Bloomington Indiana Posts: 1,041	Re: And now speedo problems Make sure the speedo cable housing is firmly clipped into the back of the speedo. It clicks TWICE going in, or at least mine does. I didn't get it in all the way last time, and: no speedometer. Not having it in all the way gives enough slop for the speedo cable (which is helical-wound, so, when turned, it will run up against one end) to pull out on the other end. When you put the drill on it, you may have pushed the cable in so it engaged, then when you mount it to the transmission it walks out. So even if you didn't mess with the speedometer end of the cable this time, make sure that it is clipped in all the way on the back of the speedometer. __________________ Rich Weyand 1978 K10 RCSB DD.

05-27-2014, 06:03 PM	#3
Skunksmash Registered User Join Date: Sep 2012 Location: TX Posts: 1,014	Re: And now speedo problems Thanks I'll give that a try. And report back what happens.

05-28-2014, 04:01 AM	#4
Skunksmash Registered User Join Date: Sep 2012 Location: TX Posts: 1,014	Re: And now speedo problems You were right, it wasn't clicked in all the way. However, the needle is a little..erratic. I would say that its accurate, but its not smooth. The needle sort of jumps around a bit. Say you're going 30mph. The needle will bounce between 29, 30, and 31 mph. Before it didn't really do that. Is this something that might straighten itself out?



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.