speedometer too fast
 

I have a 1990 SR5 pickup....I bought the truck 2 weeks before Christmas...so I'm still getting the "bugs" out....making it mine, so,to,speak....the speedo was off by app 12 miles per hour when I got it, and now after having to replace thr tranny, it's still off by 12 miles per hour....My question it, the plastic gear....where the speedo cable connects has 18 teeth....can you replace the gear with 1 tooth difference...or will I have to replace the gear on the out-put shaft as well...I have to mention this truck is 4WD with an automatic tranny....thanks

Also the code for the differential shows it to be a 4:56....and I have 31X10.50 15 tires

What size are your tires? If they are different than what the truck came with stock, your speedo will be off. The best thing to do is know how far off it is and learn to correct it in your head. Mine is off by almost 20 miles per hour when cruising at 55, so I know if the truck says I'm going 75, I'm actually doing 55.

Also does it look like your guage cluster has ever been apart ( different colour, leds, white face) if so the PO might have had the needle off and didn't get it back on just right. I believe thats whats wrong with mine as i am running stock tires and gears and mine if off about 10 mph.

If your tires are larger than stock your speedo will be slower if the truck has been regeared too low for your tires it will be fast.

stopwatch measure time traveled over a known distance (1 mile)

GPS is the best...

mine isd 10% faster than speedo indicates, with 32" tires....I just deal with it ;)

i think you can swap the speedo gear to correct however

Mine is 10mph faster over the speedo ALL the time.
Then the added 1-2% from over-sized tires, it changes from 9-10Mph

The tires are the size that came on the truck when it was new.....according to the Toyota dealer....I think, however, that the tranny had been changed before I got the truck....and I know that the tranny I put back in came out of a 4runner....with 4:10 gears....the speedo gears were identical in both trannys.....the dealer could'nt tell me if I could swap the speedo gears....I don't think he knew a lot of technical things...as far as the needle being off....I don'tthink it is when the truck is stopped it is exactly on zero....I may have to learn to get used to the thing being off....and I don't always have my GPS in my truck.....thanks for all the replies

Is it 12 miles per hour off at all speeds or is it a percentage off, like 12@60, 6@30, etc.? An automatic with 31" tires should have 4.88 gears, so you might want to verify your axle gears:
- http://www.4crawler.com/4x4/4R_TechI...oDetermination

And check with a local speedometer repair shop, they can give you some options on recalibration. I used to run a recalibration gear box on my '85 to fix a 10% speedometer error due to 33" tires and 5.29 gears.

It's off by 12 mph at all speeds....thanks for the note about the gearing....when I first got the truck, it had 31's, and not knowing what gearing I had, I had a set of 235x75x15's put on...(that's whats on my 4runner)...the speedo was off by 20 or-so mph...then I was told about my axle code...so I had 31's put on...and the speedo was only off by 12mph....my 4runner has 4:10 gears, and came with 235X15's...and the speedo is fine....this is not a big deal....but I don't like tickets...and I don't like going too slow in front of another car....I guess I'm just too anal......

If it is 12 off at all speeds, then simply resetting the speedometer needle would do the trick. I had that problem on my VW when I had taken apart the instrument cluster to swap out a tachometer and speedometer. In doing so, I had to pull the needle off the speedo and I didn't carefully note what position it was in on the shaft. Shoved it back on where I thought it should go and I was about 10 MPH off at all speeds. What I did to fix it was pull the speedo out again and noted where the needle sat at 0, then lifted the needle off again. Then I reset it to be about 10 MPH slower at "0" than it was before and that fixed it. The shaft of the speedometer gauge has some splines on it that fit into small teeth inside the center of the needle, so once I was close, it was just a matter of moving the needle over one set of splines and resetting it.

FYI i've never heard of an replacement speedo gear for Toyotas. Has anyone else?