3200 RPM @ 60 MPH? Something's wrong here...

Northern Chev · Post by **Northern Chev** » 29 Mar 2012, 14:34

1998 S70 GLT SE (LPT) w/ automatic transmission

With the selector in "D" and at a steady highway speed this car spins the engine at 3200 RPM at 60 MPH. This does NOT seem right to me.

- The car accelerates, shifts and runs at lower speeds just fine (so it seems).
- The transmission does not feel or sound like it's "slipping".
- The transmission fluid is average and smells old.
- In drive the car shifts 1-2 fine, 2-3 delayed until 30 minimum and that's it, no 4th gear.
- If you let off the gas when going 60 MPH @ 3200 RPM in top gear the engine RPM drops down to somewhere around 1500 RPM(ish). Then when you re-apply the gas it goes back up to 3200 RPM.
- If you are cruising at a steady 60 MPH @3200 RPM and floor it the car takes off like a rocket (no slipping so it would seem).

It just seems like it's not in top gear. I do NOT count all 3 up-shifts but the car moves instantly when you hit the gas at any speed. I detect no slippage when flexing the gas pedal at any speed. The car responds instantly.

I have no 4th gear and I have codes P1734 and P1618 and a flashing arrow on the dash.
As well, car is now locked in 4th gear and won't come out unless you shift to neutral.

Something's wrong here. Considering it shifts pretty normal otherwise what do I look for?

Billc1015 · Post by **Billc1015** » 29 Mar 2012, 14:50

Is the arrow light on in the instrument cluster?

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Post by **jblackburn** » 29 Mar 2012, 15:02

Hmmmmm...I think a turbo would only be at that RPM without being in 4th gear. Could be wrong; I usually make it downshift to 3rd instead of just unlocking the torque converter in 4th for more power.

Get past 30 and let go of the gas to see if you feel the final upshift to 4th. Mine will do it with no throttle with a noticeable gear change.

Otherwise, the torque converter solenoid isn't locking up, though I don't know why it would do that aside from a bad solenoid.

Post by **Ozark Lee** » 29 Mar 2012, 15:04

You should get what feels like an additional shift when the torque converter lockup solenoid engages.

...Lee

Northern Chev · Post by **Northern Chev** » 29 Mar 2012, 15:44

NEW DEVELOPMENTS - Just tested again

The car does NOT in fact shift into all 4 gears. New test results follow:

If I shift the car manually while accelerating here is what happens -->
- Take off in first gear is fine.
- Pushing the gear selector to "2" the car shifts fine.
- Pushing the selector to "3" does NOTHING. No matter how fast or slow you are going it stays in 2nd.
- Pushing gear selector to "D" makes the car shift into what feels like 3rd and runs 3200 RPM @ 60 MPH.

But! Just as I was returning home from this test the car threw a Check Engine light AND a flashing ARROW on the dash and is positively LOCKED in 4th gear and will NOT come out of it unless you shift to neutral or reverse or park. Forward gear is locked into 4th no matter how fast you are going. It stalls the engine at a stop light because it's in 4th. It's stuck in limp home mode.

Engine codes read P0734 Gear 4 Ratio Incorrect and P1618 Manufacturer Control Aux Inputs Aux Outputs... this is new

Northern Chev · Post by **Northern Chev** » 29 Mar 2012, 16:52

MORE New Developments -

I let the car sit an hour after driving it home locked in 4th gear.

It now is NO LONGER locked in 4th gear but has gone back to it's original state of having all forward gears EXCEPT 4th. And is back to revving to 3200 RPM at 60 MPH. ...sigh.

Hopefully this no-4th-gear thing is some solenoids or something I can replace fairly easily? Anyone?

Billc1015 · Post by **Billc1015** » 29 Mar 2012, 17:10

It sounds like you are stuck in limp home mode.

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