1989/c 1500 pick up gages

[steveb2001ZR2]

My speedo is way off, when Iam running say 55, it reads 70, sometimes 80, My wife ran next to me she was running 55, The truck said 70, sometimes gos to 80 or even higher, also the oil presure gage tops out also, it stays this way, when engine is shut off also, tires are the right size, truck all stock, got it off and old guy,he said it didnt bother him so he never fixed it,I like to know how fast iam going.
thank you

[mudrunner80]

This may sound dumb but did you check all the Wire connections on the transfer case? Something similar happened to me. It was crap that worked its way in the connectors. I cleaned them all up and snugged em tight and it worked. Hope its that simple for ya. Mine never is lol

[steveb2001ZR2]

I will check it all out, it dont have transfer case, 2 wheel drive, but hey ,I will check this all out, and let you all know, mean time, if anyone has anything else please add.
thank you

[2000CAYukon]

Do you know if they put a different transmission in the truck? There are small gears in the transmission that can be changed based on tire size changes and rear end gear changes. See http://www.transmissioncenter.net/sp...n_______va.htm

This may or not be your issue but if the signal from the VSS is good, you may have to check to see what gears are installed in the tranny.

//2000CAYukon

[steveb2001ZR2]

I think it has org. trans, truck dont seem to had anything like that done, to look at it, what I have seen it do is give me all diff reading, at the same speed, one day it will read 50, the next say 70 , it varys, of couse I dont know that Iam going 35 when it reads 50, but Iam going by the feel,and going with the flow of traffic on a 35 speed zone.
Will check all of the above as soon as it warms up some.

[steveb2001ZR2]

Ok I changed the oil today, and seen a tag on the trans. remanufactured for GM replacement trans. I would think they would have put the same thing in it , that came stock,but now Iam wondering , did they?, does anyone know what numbers I look for to find out what it is, so I came go to the above link and find out what gear I need for the speedo to work right,it has the 16 bolt pan if that helps.
the trans seems find, shifts hard when cold but after it warms up, shifts fine, I also have the filter and gasket to change that.
judt got this truck from an old guy, he always took it to the dealer he claimed to get serviced.I found nothing but GM parts on it right down to the new plug wires.
Need that speedo reading right