FireInMe17

Ok so ever since I got this car, I never thought that the transmission was working the way that it should be. I always hear about people with 3.1L Automatics that can hold 100mph with like 3000rpm with the 3.23 gears. Well for me to hold that I need around 5000-6000rpm.

Everyday I drive this car about 80-90 miles on the highway, and I like to cruise at 70mph, and to do this, I need 3000rpm. Doesn't sound right does it?

Then I get into the calculators and they say that for the size tire that I have with the gearing that I have with 3000rpm I should be able to hold 103mph.

(13 in radius tires, 3.23 rear, .7 4th gear)

Now when I do the same thing and change the gear from 4th to 3rd(.7:1 to 1:1) it gives me 72mph which sounds right for what my car does.

So what does this mean? Do I have no 4th gear? Is there something wrong with my 4th gear switch or TCC or Torque Converter? This is really starting to frustrate me, and I would like some help with it.

Heres a video of my car going through the motions shifting:

http://www.youtube.com/watch?v=5gqoFD64ArA

RBob

iTrader: (1)

The cluster area is too dark to see well in the video. With the 3.23's and the TCC locked the RPM should be about 2250 at 70 MPH. Note that the tach's in these cars can read high. Some are so bad that idle shows at 2,000 RPM.

Anyway, back to the tranny. First test to see if the TCC is locking. Two things to try to check for this. Cruising steady on the highway, engine up to temperature, wait about 10 seconds. Then depress the gas pedal just enough so that the tone of the engine changes. While doing this watch the tach. It should stay at the same reading.

If the tach goes up then the TCC isn't locked.

The other test is under the same conditions (steady cruise, warmed up, ...), leave your foot on the go-pedal, use the left foot and gently depress the brake pedal enough that the brake lights would turn on.

In this case the RPM should suddenly increase as the TCC unlocks. Release the brake pedal and within a few seconds the TCC should re-lock and the RPM drops back down.

RBob.

FireInMe17

I've done that before, and it works. So either I have no 4th gear(bad 4th gear), the car doesn't know its in 4th gear(bad 4th gear switch?) or the Torque Converter isn't locking up correctly(Damaged Converter or TCC switch).

The other possibilities I guess is that my tach is wayyyy off or something with the VSS or governor or something?

Well now that I think about it, the car gives a code 24 every now and again, which is for a bad, or short circuiting VSS, could this be affecting it this badly? I wouldn't think so but then again, I have no idea why its doing what its doing.

I will go take another video of the tach only and then at the end I'll switch to the speedo so you can see at what speed the Torque converter locked up at.

FireInMe17

Ok heres more videos...

Can you tell I'm wearing white shorts? haha

http://www.youtube.com/watch?v=hn0GcZP-Slo

http://www.youtube.com/watch?v=nm4dhuAe0VA

FireInMe17

Help?

RBob

iTrader: (1)

A VSS malfunction code (24) will prevent the TCC from locking. The lockup points are based on the vehicle speed. No move, no lock.

In the videos, to me, it looked like the TCC was unlocked until the very end. So either it finally locked or you lifted some. With the high stall converter used in the 6's, that is where in the RPM band the engine will be in 4th with an unlocked TCC.

It also appeared that the RPM was unsteady, again pointing to the TCC not being locked.

A bad 4th gear switch won't prevent the TCC from locking. The ECM just won't use the correct set of tables. That is it will always use the lo gear or hi gear tables dependent upon the failure mode of the switch.

Can you get a video of the tach while pulling out from a stop up to about 60/65? Warm engine, put shifter in OD, and accelerate evenly.

In that, should be able to see each shift, along with the TCC locking in either 3rd or 4th. With enough throttle it shouldn't lock until in 4th.

RBob.