Speedometer Cable Routing

[Legolas894]

Just going to install a new speedometer cable on my 1967 GMC 910 Fleetside. It will go from the manual three speed to the dash. Both ends of the old cable are still attached to where they should go. Any special instructions on how to route the new cable? I saw that you should lube the ends of the cable. Can you use Automatic transmission fluid for this or grease or just oil?

I've got an appointment to get the safety inspection done for tomorrow so I'm trying to get all the required stuff in tonight. Got the mirrors on, brake lights, windshield washers all working. Not sure if the speedo needs to work but not taking any chances.


Thanks!

[spinning wheels]

Originally Posted by Legolas894

Just going to install a new speedometer cable on my 1967 GMC 910 Fleetside. It will go from the manual three speed to the dash. Both ends of the old cable are still attached to where they should go. Any special instructions on how to route the new cable? I saw that you should lube the ends of the cable. Can you use Automatic transmission fluid for this or grease or just oil?

I've got an appointment to get the safety inspection done for tomorrow so I'm trying to get all the required stuff in tonight. Got the mirrors on, brake lights, windshield washers all working. Not sure if the speedo needs to work but not taking any chances.


Thanks!

I just purchased a speedo cable for my truck. The instructions state to lubricate all of the cable. You can obtain cable lube at any motorcycle shop.
ATF is hydraulic fluid, and not a lubricant. If its a new cable, they usually supply some cable lube and instructions with the speedo cable.

[Legolas894]

Thanks for the reply. It's a new cable but no lube came with it. Do you think lithium grease is ok?

[68C15]

ATP brand part # 209 IIRC is speedo cable lube. a good parts store should have it. I would shy away from WL as it can become solidified over time..

[Legolas894]

Got the lube and removed the cable from the sheath. Cleaned off the sticky grease and put it all back together. This time the speedometer needle would pulse a few times but only when I put the clutch in. Parked it again, took the speedometer gear housing off and pulled the red plastic gear out. Half of the teeth were worn off. So, I guess I know why the speedometer is pulsing!

The plastic gear is red with 21 teeth. It's about 2 1/4" long. Any idea where to get a new one!

Thanks

[cdowns]

speedo ccable lube has graphite in it to polish the inside of the housing while it rotates and so you dont have a jumpy needle// white lithium does the job for aewhite then clumps up hdrys out and hardens up causeing erratis needle movements

[Green Machine]

I get the gears from the dealer, easier to return if you or they mess up.

[Legolas894]

Originally Posted by Green Machine

I get the gears from the dealer, easier to return if you or they mess up.

You mean like a Chevy/GMC dealer? I'm amazed they would still have parts like that.

[Green Machine]

Yep - Chevy dealer, most of those gears were still used in similar/same trannys well into the 80's. You can get them online too, $5-$10 part, just easier if you can show the parts guy what you need. If they mess up, they can send it back easier than you can. I buy alot of other stuff online, this is just one of those parts that seems easier to me to go to the dealer if they are fairly close.

[jbristo67]

DO manual and automatics use different cable lengths??

[spinning wheels]

Originally Posted by jbristo67

DO manual and automatics use different cable lengths??

I just installed an 80" cable. There are two longer sizes, but on a 2wd truck, 80" is long enough. The manual uses a push on type, at the trans. The auto uses threaded ends on speedo and trans.

If you can, follow the original cable's route. I just couldn't use the stay that was originally on the truck. What a PIA, I am using a stainless steel hose clamp, wrapped around the frame. Just to keep the cable from touching the exhaust.

[Legolas894]

Thanks to GreenMachine for the dealer tip. Sure enough, the dealer had two red 21 tooth speedometer driven gears in stock. He was very helpful. In case anyone needs this, the GM part number is 3987921. It was $7.09 + tax! What a deal.

Got it on tonight and it's working. I just have to see how close it is to the actual speed with my GPS. I'm in Canada so I'll have to get used to MPH instead of KM/H but that's ok. I couldn't stand driving without the speedometer.

Thanks for your help!