Speedo not work
Thread Starter
Racer
Joined: Sep 2002
Posts: 293
Likes: 0
From: Englewood CO
Speedo not work
I disconected my speedo cable from the tranny and hooked up the drill and the speedo did move, so I assume the problem is inside the tranny. I replaced the gear inside it and that did not help. Just to confirm what I think it is I am going to ask if it is the gear that gets "knocked" out of place in the tailshaft of the tranny causing the problems. If so, is this a hard job to do with the tranny in the car.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Re: Speedo not work (79corvette)
No the main shaft gear is not likely the cause. I would look at the cruise module or the cables. The cruise module is a common source of problems. The rotation of the cable is CCW.
Melting Slicks
Joined: Aug 2000
Posts: 2,310
Likes: 1
Re: Speedo not work (79corvette)
I agree this isn't a common problem.
I thought it was the problem with mine so I replaced the driven gear.
I can say that mine was not a difficult job because I had the plastic gear that clips on versus the pressed on metal gear.
My gear WAS cracked, but I may have done that during removal.
As far as replacing the driven gear; there are a couple of good books out there with illustrations (I got one from the local library, but maybe they're on the Web too) but it basically goes like this:
Remove the speedo driven gear.
Remove the drive shaft.
Remove the tailshaft (4 bolts).
Remove the metal retaining clip for the plastic gear or "pull" the metal gear (that would be more difficult).
Replace with new gear & reverse the rest of the steps.
I already had my trans drained (for a shift kit) so I didn't have to deal with fluid dripping.
I also bought all of the new gaskets (tailshaft gasket, rear seal, driven gear seals).
When I finally got it back on the road, the speedo still didn't work; turned out to be a break at the CC transducer :rolleyes: But at least I have a new gear and gaskets/seals.
Good Luck.
I thought it was the problem with mine so I replaced the driven gear.
I can say that mine was not a difficult job because I had the plastic gear that clips on versus the pressed on metal gear.
My gear WAS cracked, but I may have done that during removal.
As far as replacing the driven gear; there are a couple of good books out there with illustrations (I got one from the local library, but maybe they're on the Web too) but it basically goes like this:
Remove the speedo driven gear.
Remove the drive shaft.
Remove the tailshaft (4 bolts).
Remove the metal retaining clip for the plastic gear or "pull" the metal gear (that would be more difficult).
Replace with new gear & reverse the rest of the steps.
I already had my trans drained (for a shift kit) so I didn't have to deal with fluid dripping.
I also bought all of the new gaskets (tailshaft gasket, rear seal, driven gear seals).
When I finally got it back on the road, the speedo still didn't work; turned out to be a break at the CC transducer :rolleyes: But at least I have a new gear and gaskets/seals.
Good Luck.
