Rpm's @50 mph
- Thread starter mx3_ryder
- Start date
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streetglideok
Full Access Member
What gear? Stick or auto?
auto
eradicator006
Full Access Member
Stock size tires? That seems kind of high. That's about where mine is at 100km/h (62mph)
EDIT: Wait a sec. Mine is about 2k at 110km/h. I find that's where I get the best mileage at and it doesn't have to downshift to get up a hill.
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streetglideok
Full Access Member
Ok, still need to know what gear, it could be fourth, third, or second and which automatic, or at least the year. I think the two automatics used had different 4th gear ratios. Third gear was the same, 1:1
CactusJacked
Full Access Member
His 02 has the 45RFE trans, and 4th gear is a .75:1 overdrive. With the factory 3.73 gears and factory 235 70R16 tires (29"), at 50 mph in 4th the rpm's would be 1,622. If 4.10 gears were swapped in, rpm's would be 1,778.
However, in 3rd gear (1:1) with 3.73 gears, rpm's would be 2,161. With 4.10 gears, rpm's would be 2,375.
Can you feel the trans going into all 4 gears? Because if you have a factory setup (tires & gears), it's pointing to the trans staying in 3rd, or it's slipping.
However, in 3rd gear (1:1) with 3.73 gears, rpm's would be 2,161. With 4.10 gears, rpm's would be 2,375.
Can you feel the trans going into all 4 gears? Because if you have a factory setup (tires & gears), it's pointing to the trans staying in 3rd, or it's slipping.
dude1116
Full Access Member
Mine doesn't like to lock the TC at 50MPH which actually causes it to sit at 2k RPM. It locks the TC at 55 and RPMs are down to about 16-1700. I have an 04 with a 42RLE.
CactusJacked
Full Access Member
Which has a .69:1 overdrive.
tjkj2002
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Heck I run about 2100-2200rpm's at 50mph.
ChiefRudy
Full Access Member
streetglideok
Full Access Member
Ok based on him having a 45RFE, and 235/70r16 tires and stock gearing, according to the gear calculator sticky'd at the top of this forum section, at 50mph it calculates 1623rpm in fourth gear. 2165rpm in third gear. So mx3, sounds to us if all that info matches, your ****** isn't shifting into fourth. I'd check to see what the rpms are at 70mph. At 70mph in fourth gear, it should be 2273rpm, and if it's in third, 3030rpm. That's in the ballpark at least.
Gear Ratio Calculator
Gear Ratio Calculator
CactusJacked
Full Access Member
Darn if all that ^ doesn't sound familiar!!! 
This is a quick and easy calculator that doesn't cause migraines nor take minutes to get the answer like the stickied one: Speed/RPM Calculator
This is a quick and easy calculator that doesn't cause migraines nor take minutes to get the answer like the stickied one: Speed/RPM Calculator
Gyro
Full Access Member
Drivers side of shift lever.
Should be a yellow light on cluster OD off.
Gyro
Should be a yellow light on cluster OD off.
Gyro
Thanks, guess it resets its self when vehicle is turned off, so that wasn't it. Any suggestions is to why I don't have 4th gear?
Edit: I just went out at break and ****** does shift all 4 gears, guess I wasn't noticing 4th before as it does shift really smooth. My overdrive button works perfect to. Also when going 50 MPH, I can get RPM ranges of 1600-2000 depending on accelerator position and road surface. So I guess nothing wrong other than she's a gas guzzler.
Edit: I just went out at break and ****** does shift all 4 gears, guess I wasn't noticing 4th before as it does shift really smooth. My overdrive button works perfect to. Also when going 50 MPH, I can get RPM ranges of 1600-2000 depending on accelerator position and road surface. So I guess nothing wrong other than she's a gas guzzler.
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streetglideok
Full Access Member
Darn if all that ^ doesn't sound familiar!!!
This is a quick and easy calculator that doesn't cause migraines nor take minutes to get the answer like the stickied one: Speed/RPM Calculator
I didn't think the one that got stickied was all that complicated. Gives you some pretty exact numbers. At the bottom with the spreadsheets it gets a bit cluttered but that was all.
streetglideok
Full Access Member
Honestly, at 50mph, I would click off the overdrive button. Too low of RPMs, will hurt fuel economy as the engine is below the torque band, and puts undo stress on the overdrive clutch pack.
My setup is far from stock
BUT I never run 50 mph with the overdrive on, its always off at that speed, lugs down too much for me.
Did try it this morning worn down 265-75-16 tires with 4.10s at 50 in overdrive its about 1680/1700. More for those ever considering going to 4.10s and larger tires.
BUT I never run 50 mph with the overdrive on, its always off at that speed, lugs down too much for me.
Did try it this morning worn down 265-75-16 tires with 4.10s at 50 in overdrive its about 1680/1700. More for those ever considering going to 4.10s and larger tires.
