Automatic Tranny: Highway rpm Off & On Throttle?
10-17-2011, 10:33 PM
#1
2nd Gear Member
Thread Starter
Join Date: Jul 2011
Location: San Diego, CA
Posts: 187
Automatic Tranny: Highway rpm Off & On Throttle?
My automatic is doing something interesting I didn't really notice before, hoping to see if anyone else has experienced it?
Cruising at steady throttle in 5th gear at 70 mph, my rpms stay at around 2,100 (3.31 gearing
).
When I lift off the throttle, the rpms drop slightly to about 1,900, but when I apply the throttle again, the rpms go a couple of hundred higher than the original cruising rpms to about 2,300 rpms, and the after a second or two, drop down back to the normal 2,100 rpms.
It's almost like the car went down a gear and then back to fifth, even though I know it stayed in 5th gear the whole time. I tried the same thing in 4th gear, keeping the OD off, and it does the same thing.
It could be normal, just not sure. Anyone else notice this?
Cruising at steady throttle in 5th gear at 70 mph, my rpms stay at around 2,100 (3.31 gearing
). When I lift off the throttle, the rpms drop slightly to about 1,900, but when I apply the throttle again, the rpms go a couple of hundred higher than the original cruising rpms to about 2,300 rpms, and the after a second or two, drop down back to the normal 2,100 rpms.
It's almost like the car went down a gear and then back to fifth, even though I know it stayed in 5th gear the whole time. I tried the same thing in 4th gear, keeping the OD off, and it does the same thing.
It could be normal, just not sure. Anyone else notice this?
Last edited by SD 197; 10-17-2011 at 10:35 PM.
10-17-2011, 11:32 PM
#3
2nd Gear Member
Thread Starter
Join Date: Jul 2011
Location: San Diego, CA
Posts: 187
10-24-2011, 07:42 PM
#5
3rd Gear Member
Join Date: Jun 2010
Location: RI
Posts: 690
It is the converter unlocking (rpm rises) then locking (rpm drops). The more torque the engine makes, the more it will happen. The more it happens, the more heat is generated in the tranny. The rpm rise is sorta like slipping the clutch in a manual car.
10-24-2011, 08:11 PM
#6
My automatic is doing something interesting I didn't really notice before, hoping to see if anyone else has experienced it?
Cruising at steady throttle in 5th gear at 70 mph, my rpms stay at around 2,100 (3.31 gearing).
When I lift off the throttle, the rpms drop slightly to about 1,900, but when I apply the throttle again, the rpms go a couple of hundred higher than the original cruising rpms to about 2,300 rpms, and the after a second or two, drop down back to the normal 2,100 rpms.
It's almost like the car went down a gear and then back to fifth, even though I know it stayed in 5th gear the whole time. I tried the same thing in 4th gear, keeping the OD off, and it does the same thing.
It could be normal, just not sure. Anyone else notice this?
Cruising at steady throttle in 5th gear at 70 mph, my rpms stay at around 2,100 (3.31 gearing
). When I lift off the throttle, the rpms drop slightly to about 1,900, but when I apply the throttle again, the rpms go a couple of hundred higher than the original cruising rpms to about 2,300 rpms, and the after a second or two, drop down back to the normal 2,100 rpms.
It's almost like the car went down a gear and then back to fifth, even though I know it stayed in 5th gear the whole time. I tried the same thing in 4th gear, keeping the OD off, and it does the same thing.
It could be normal, just not sure. Anyone else notice this?
First off, if you are cruizing at 70mph @2.1rpm...you are currently in o/d my friend. When you let off the throttle the decrease in rpm is the converter at work, but depending on your throttle input upon the next press, you are dropping her back in 5th (producing the higher rpm) quickly followed by o/d engaging once again (lower rpm). Right or wrong it's no biggie, mine does the same thing and I have the same gear.
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