My 89 Camaro runs at high rpms at highway speeds. I'm sure the car is in overdrive. I checked the tach, thats accurate, changed filter and put in new tranny fluid, Can you guys suggest anything else ?

 

How high is high?

What's the engine RPM at "X" road speed?

 

Also tire size and diff gear ratio

 

This all happened when my radiator blew and the engine got hot. The repairs were done but afterwards I noticed that at 60 mph I am at 3300 rpm.

 

How do you know the tach is accurate?

You can check the accuracy of the speedo with a GPS speed app with your phone.

I had a 91 454SS pickup truck. OD transmission, 4.10 gears and 28" tall tires and it was close to 3000 rpm at 60 mph.

 

checked the tach with a aftermarket tach, both read the same exact rpms at highway and regular driving speeds. The car always ran 2000 rpm at 60 before the radiator blew

 

torque convertor locking up? sounds like its not locking at high speeds. even so that still seems pretty damn high

 

I manually shifted the car and it went into all gears perfectly including o.d. , I'm leaning towards the tcc solenoid being bad

 

if you get under there, apply 12v to one of the lines on the tcc solenoid and see if it clicks.

 

Thanks Zed , I'm kind of a novice when working on transmissions, where would thee TCC solenoid wires located ?

 

Math says 2283

 

If it was just the converter not locking, that would add 200 RPM at a steady cruise, not 1300.
No way this thing is shifting to OD, no matter where the shifter is placed.
2000 at 60 should be a 3.42 if 700R-4, so that should be 3100 at 60 in third with the converter unlocked in third. 2000/0.696=2900+200 slip.
If this is a T5 with the 0.63:1 fifth, then the math works with a 3.73 or 3.91 axle, depending on tire size.

 

yeah thats why i said it still seems pretty damn high.

i think with my 305 with the 700r4 at 60mph (somewhere near ~100km/h here in aus) its in the mid 2000's in 4th without lockup

 

Just took my 89 Camaro out for a drive, at a steady speed while in od I tapped the brakes and the rpms went up 200 to 300 rpms, that tells me my torque converter is working so I can rule that out