Speedometer problems - mystery

[James Moore]

I have a 95 4-Runner that is driving me and my mechanic nuts regarding the speedometer. At about 110,000 miles the speedometer quit. The mechanic replaced the speedometer gear at the transmission. Withine 2 weeks the gear (nylon) stripped out again. I replaced it a second time and again, it stripped out within a couple of hunderd miles. The mechanic then replaced the cable, although using a reversible drill to turn the original cable had not indicated any problems with the cable or the speedometer head in the dash. When he put the third gear in, he also replaced the bushing around the gear since he had heard it could cause problems as well. About 200 miles later, the gear is stripped again.

I have heard there is another mechanic here in my town that is fighting the same problem on another 4-Runner so I am wondering if this is a problem that others have dealt with.

I have attached a couple of pictures depicting the stripped out gear and the entire gear assembly that has been replaced numerous times now.

Any help would be greatly appreciated.

Thanks

Jim Moore
Texas

 

[TSP-MIKE]

There is only 2 things that i can think of that can do this. 1. is the gear is incorrect and is too small. 2. the gear that spins the speedometer gear is bad ( maybe bent or chipped ). You will have to remove the rear tail housing to inspect it.

Mike

 

[James Moore]

Mike,

Thanks for the reply. My mechanic put a new gear in and did not hook up the cable. This was to check and see if the gear was getting chewed up by something wrong on the transmission end. Ran it about 1000 miles or so and the gear was fine. He has now hook up the cable at the transmission but left it disconnected at the speedometer head. This is to see if there is something happening in the cable (although it is a new cable). After another 1000 miles or so (since I cannot tell exactly), we will look at the gear again. If it is still ok, he feels the problem will have to be in the head somewhere and intermittent.

Pain in the butt. My son got a speeding ticket the other day in this vehicle. Still his fault but tough when you are trying to gauge your speed off the tach.

Thanks again,
Jim

 

[Ed Oldroyd]

Speedometer gear wear

I worked in a Chev dealership for way too long and ran into this speedometer gear several times. You received good advise from Mike. I think you are wasting your time doing all the other stuff. When you get the speedometer drive gear out you will see that it is worn and rough causing it to wear out the plastic driven gear. (it is a steel gear). You will need to remove the drive shaft and tail shaft housing and devise a puller as it will be pressed on.

Ed

Does anyone know how I can find a listing of driven gear size for Toyotas? I need one that is 31 or 32 tooth to replace the 26 tooth in my trans. Someone before me replaced the rear 3.07 differential with a 3.73 and now my speedometer reads 20% to fast.