My 97 Corolla seems to shift hard with the ac on. Otherwise it shifts perfectly with it off. I know it can't be the fluid because its fresh. Any ideas what could be the cause?
rough shifts when ac is on
- Thread starter brian12
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A small engine will drag more with the AC on.
You can feel it while driving.
For a bunch of reasons, feeling harsher shifts with the AC on could be very normal and expected.
A 472 cubic inch Cadillac would not be as offended.
You can feel it while driving.
For a bunch of reasons, feeling harsher shifts with the AC on could be very normal and expected.
A 472 cubic inch Cadillac would not be as offended.
Yeah, for example, computer is seeing higher load on the engine, so it may be increasing line pressure in the transmission. But this power is not going through the trans, so its a firmer shift than normal.
I wouldnt worry about it.
I specifically modified my transmission to have firmer shifts.
I wouldnt worry about it.
I specifically modified my transmission to have firmer shifts.
Originally Posted By: Onmo'Eegusee
Yeah, for example, computer is seeing higher load on the engine, so it may be increasing line pressure in the transmission. But this power is not going through the trans, so its a firmer shift than normal.
I wouldnt worry about it.
I specifically modified my transmission to have firmer shifts.
That's what I think. Firmer shifts equals less slippage equals longer transmission life. However, a lot of newer cars have computers that reduce the engine torque during a shift by retarding the timing, and this might feel like the transmission is slipping excessively.
Yeah, for example, computer is seeing higher load on the engine, so it may be increasing line pressure in the transmission. But this power is not going through the trans, so its a firmer shift than normal.
I wouldnt worry about it.
I specifically modified my transmission to have firmer shifts.
That's what I think. Firmer shifts equals less slippage equals longer transmission life. However, a lot of newer cars have computers that reduce the engine torque during a shift by retarding the timing, and this might feel like the transmission is slipping excessively.
Is this the 3 speed automatic or a computer controlled 4 speed? Do your dash blend doors run on vacuum? Might have some sort of HVAC vacuum leak that's either affecting your MAP sensor or the transmission stuff. Might be able to trace its vacuum source and put a golf tee in it temporarily. AC should still work but will blow through the default blend door, usually Defrost.
Its the 3 speed so there are no sensors. I have no idea if the dash blend doors run on vacuum though. I'll check into it.
It's just that more throttle is given with the AC on, and that naturally changes the way it shifts.
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