SlowcountrySilverado
Newbie
Good evening folks,
Decently long time reader, first time poster here as I've been looking for a GMT-400 for years, and finally the stars aligned and was able to buy the truck I've wanted since I was a kid.
Some background, I drive pretty much exclusively 90's trucks, have quite a few but this is my first GM 90's truck (previously had a great '09 Silverado when I was younger), and am good with a wrench. Have done almost all my own wrench turning and builds since I was younger, and am relatively decent at it.
Here's the rundown of what has me puzzled.
Truck Information:
-1996 Silverado Extended Cab. 1 "true" previous owner.
-140,000 original miles
-Everything appears to be pretty much stock, well maintained and in relatively good order. It's a nice, tight truck. Thrilled with my purchase.
-Tires are stock 16" rims on the recommended passenger tires
What's going on:
-My speedometer is drastically off - exactly 25mph based on using Speedbox GPS along side. It's 25 MPH fast
-It feels like either I'm not getting all the way to Overdrive, or if I am getting there, it's running what feels to be pretty high RPMs. At 65 MPH I'm turning 2500 RPM which seems steep? I tried to count the shifts on the highway, and counted through 5 but it just didn't feel like it grabbed OD?
-ABS light is on. I only mention this because I have no idea if there's any possibility this is tied in and might spark some thought for someone? I don't think they're correlated but didn't want to leave it out.
- I've made it about 100 miles on 1/4 of a tank, about 50/50 highway and some stop and go. Doesn't seem like this is too terribly off.
My initial thought was did the PO stick bigger tires on at a point and re-gear but that re-gear still seems like it'd be way off for this kind of speed difference. Also logically, my brain doesn't THINK that the speedo being off would correlate to the transmission's shift points/OD running high, but again it's been kicking around in my mind and I wanted to say it out loud for piece of mind here.
Does anyone have any thoughts here?
All in all the truck drives wonderfully and very comfortable. Just don't want it working too hard, and 2500 RPM at 65MPH seemed...odd. And the speedo being +25...when I changed tires in my old Jeep I changed out the mechanical gear, in my Bronco I was able to calibrate the speedo on the dash. No idea what's going on here.
And I know I have to pay tax, so here's the photo tax. The Silverado parked at home next to my '95 Bronco. I'll take better photos this weekend and do a proper intro.
Decently long time reader, first time poster here as I've been looking for a GMT-400 for years, and finally the stars aligned and was able to buy the truck I've wanted since I was a kid.
Some background, I drive pretty much exclusively 90's trucks, have quite a few but this is my first GM 90's truck (previously had a great '09 Silverado when I was younger), and am good with a wrench. Have done almost all my own wrench turning and builds since I was younger, and am relatively decent at it.
Here's the rundown of what has me puzzled.
Truck Information:
-1996 Silverado Extended Cab. 1 "true" previous owner.
-140,000 original miles
-Everything appears to be pretty much stock, well maintained and in relatively good order. It's a nice, tight truck. Thrilled with my purchase.
-Tires are stock 16" rims on the recommended passenger tires
What's going on:
-My speedometer is drastically off - exactly 25mph based on using Speedbox GPS along side. It's 25 MPH fast
-It feels like either I'm not getting all the way to Overdrive, or if I am getting there, it's running what feels to be pretty high RPMs. At 65 MPH I'm turning 2500 RPM which seems steep? I tried to count the shifts on the highway, and counted through 5 but it just didn't feel like it grabbed OD?
-ABS light is on. I only mention this because I have no idea if there's any possibility this is tied in and might spark some thought for someone? I don't think they're correlated but didn't want to leave it out.
- I've made it about 100 miles on 1/4 of a tank, about 50/50 highway and some stop and go. Doesn't seem like this is too terribly off.
My initial thought was did the PO stick bigger tires on at a point and re-gear but that re-gear still seems like it'd be way off for this kind of speed difference. Also logically, my brain doesn't THINK that the speedo being off would correlate to the transmission's shift points/OD running high, but again it's been kicking around in my mind and I wanted to say it out loud for piece of mind here.
Does anyone have any thoughts here?
All in all the truck drives wonderfully and very comfortable. Just don't want it working too hard, and 2500 RPM at 65MPH seemed...odd. And the speedo being +25...when I changed tires in my old Jeep I changed out the mechanical gear, in my Bronco I was able to calibrate the speedo on the dash. No idea what's going on here.
And I know I have to pay tax, so here's the photo tax. The Silverado parked at home next to my '95 Bronco. I'll take better photos this weekend and do a proper intro.