Just had the 32rh (904) 3 speed automatic in the 2002 rebuilt. Shop said they put new torque converter in it. Everything seems fine so far but I've noticed when im going down the highway at 55mph I'm running 2500rpms. Is this normal?
Are these RPMs normal for a 32RH?
- Thread starter Jellis
- Start date
KennethS
TJ Expert
Gear ratio calculator says around 4.33:1 gear ratio with those tires and RPM @ 55 MPH. Are you sure the speedometer is accurate?
Man I wouldn't know for sure. I'll say this. It didn't run at 2500 with the factory tranny in it. But I had a ton of other issues with the factory tranny. Not sure if the other tranny should have been running higher or if this one is too high.
KennethS
TJ Expert
Well, it’s difficult to give you any help over the internet with the limited information available. You need to know 3 of the 4 variables in order to calculate the unknown (tire diameter, RPM, MPH, gear ratio).
It’s easy enough to compare the dash speedo reading vs. a GPS speed reading, and you can lift a wheel and count revolutions of tire vs driveshaft to get a gear ratio estimate.
The only thing I can think of is to ensure you feel the transmission shifting to third gear to make sure it’s not in second, which would make the RPM a lot higher than typical.
It’s easy enough to compare the dash speedo reading vs. a GPS speed reading, and you can lift a wheel and count revolutions of tire vs driveshaft to get a gear ratio estimate.
The only thing I can think of is to ensure you feel the transmission shifting to third gear to make sure it’s not in second, which would make the RPM a lot higher than typical.
I know the tires are 33's. There is a rough country lift so the speedometer is off. I have a 2002 X model so according to my research its most likely a 373 gear but could be a 3.07. I will download a speedometer app to verify the speed and get back with you. I can feel the transmission shift into 3rd gear. What i'm not feeling is once its wound up to highway speed (at least 50 mph up to 65 mph it holds at a steady 2500 rpms. Does this help?
I know the tires are 33's. There is a rough country lift so the speedometer is off. I have a 2002 X model so according to my research its most likely a 373 gear but could be a 3.07. I will download a speedometer app to verify the speed and get back with you. I can feel the transmission shift into 3rd gear. What i'm not feeling is once its wound up to highway speed (at least 50 mph up to 65 mph it holds at a steady 2500 rpms. Does this help?
I know the tires are 33's. There is a rough country lift so the speedometer is off. I have a 2002 X model so according to my research its most likely a 373 gear but could be a 3.07. I will download a speedometer app to verify the speed and get back with you. I can feel the transmission shift into 3rd gear. What i'm not feeling is once its wound up to highway speed (at least 50 mph up to 65 mph it holds at a steady 2500 rpms. Does this help?
The lift height is irrelevant. To figure out the axle gearing, you need the tire size, transmission and an accurate speed that gets you into the transmission's final drive gear.
@hear is the 32rh guru.
So from 50mph to 65mph, your RPMs hold steady 2500? I would guess your torque converter is not locking. Check the torque converter clutch plug. With the recent work, I wonder if someone did not plug it back in. Or, with your speedometer being off it is causing the PCM and TCC to be off.
So from 50mph to 65mph, your RPMs hold steady 2500? I would guess your torque converter is not locking. Check the torque converter clutch plug. With the recent work, I wonder if someone did not plug it back in. Or, with your speedometer being off it is causing the PCM and TCC to be off.
33’s and 4.11 gears would end up right at 2400 rpm at 55 mph. It’s probably a slight discrepancy in the speedometer and you likely have 33’s and 4.11 gears. We can’t help any more than that with the limited info. 33’s actually are around 31.5” large and my calculations reflect that.
It can’t hold the same rpm from 50-65 mph, that makes no sense.
It can’t hold the same rpm from 50-65 mph, that makes no sense.
Agreed. The effective rolling diameter measured from the hub height X2 would be close to that.
And measure your tires. Not all 33" tires are exactly 33. I have 35" BFGs and they're 34.5". My wife's Mickey Thompson 35s are 33".
-Mac
-Mac
KennethS
TJ Expert
As said above, the lift has no impact on the speedometer being off - that is caused by tires that are a different size than factory, or a gear ratio that is different than factory.
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