Ford Mustang Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
204 Posts
Discussion Starter #1
The needle on my speedometer "bounces" when I drive my 89 GT. It is really bad in 1st and 2nd but still there in other gears. I will just be driving slowly and keeping the same speed and the needle will jump up and down anywhere from 5-20 mph in 1st. It's not really a problem but it is annoying. Does anyone know why it does this?
 

·
Registered
Joined
·
535 Posts
Could be several things. Start with the easiest and work up.

Check the gear on the speedo cable that goes into the tranny, it is on the D/S. Pull it and ensure that it is not stripped or worn. Check the gear in the tranny as well. Harder to do this one but not that difficult.

Next it could be the cable giving way or may be broken or melted. Check along the cable especially where it gets close to the D/S header (had one melt there).

Lastly your speedo is about to die. Some will last years more, some days. You can get replacements from many aftermarket place or junkyards. NOT from Ford.
 

·
Registered
Joined
·
7,142 Posts
My speedo gear is about totaled.(23 tooth) Theres about 10% left of it on one side. My speedometer seems to sweep perfectly:D
 

·
Registered
Joined
·
336 Posts
I have three here. All are bad. My 85mph was fine. I put the 140 mph in. The needle pegged itself to the trip reset button. Occasionally, it woud dislodge istelf. I stopped by Hanlon Motorsports and picked up a freshly rebuilt T5, not for this reason, of course. I replaced speedo cable while I was at it. The teeth were not chewed up on the gear the the end of the cable either. The 140mph speedo still does not operate correctly. I put the 85mph back in. It worked for two weeks, then it too started bouncing from 0-30mph. I have another 140mph out of a '92 that is said to be bad. I have not tried it.

Matt90GT claims you can try cleaning the back of the speedo with electric motor cleaner. He said he has done it three times and it has solved his problem. He also states it could potentially ruin the speedo. It's already ruined, isn't it? No loss there. I am still trying to locate some of this cleaner. My local hardware store did not carry any.
 

·
Registered
Joined
·
394 Posts
Sometime just lubing the speedo cable at the speedometer will help eliminate this problem. Disconnect the cable and just get some lube between the cable and the housing. Re-install.
 

·
Please call me Mike
Joined
·
1,567 Posts
LX302 said:
Sometime just lubing the speedo cable at the speedometer will help eliminate this problem. Disconnect the cable and just get some lube between the cable and the housing. Re-install.
use vasoline to lube it up that is what i did and it fixed myne. i wish there was a better 23 tooth speedo gear cause myne is all chewed up also
 

·
Registered
Joined
·
204 Posts
Discussion Starter #10
Thanks, looks like I'm not alone. I'll have to try some of those suggestions but now I'm off to work.
 
1 - 11 of 11 Posts
Top