Thread: RPM drops while driving

Ok our cars are FWD since the late eighties, and have never been 4x4 so I'm not sure where that came from.

Edit: just saw the video, watching it now

Okay at 0:52 when you said there it goes, that's 4th gear. It will go in 4th at a minimum of 45 mph, and higher depending on the throttle position. It seems like you're entering the freeway with a really light acceleration and naturally it shifts to the highest gear it can on light accelerations. When it downshifted, that was probably the torque converter unlocking. I'm still seeing pretty normal shifting. I wouldn't be worried. Just give it some more gas to start when entering the freeway if the weather permits, that way it will shift later. But if you like accelerating slow yet still being at the rpm's that you would be at at each shift with a higher throttle position, you can manually "shift" just to keep it from going in overdrive when you still want to accelerate.

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Originally Posted by Snoop dogg

which video 1 or 2

All 3 you posted look the same.

I don't know how much throttle you were giving it when trying to get it to downshift, but given that you were in boost it was probably at least half? The only thing I could assume about that is that it doesn't want to downshift as soon as it should. Idk, I'm N/A so if I need more speed and it won't downshift soon enough I just floor it and it always goes to the lowest gear possible and does as much as N/A 3800's can do lol.

You can delete them by clicking edit, go advanced, and delete post I think at the top. But what I said in post #23 is what I think about the video.

looks like its hooking up into over drive, wont happen till 43 to 45 mph.

Edit Post, Go Advanced, Delete

You just barley cut the "go advanced" part out. Just below that pic was the button I'm talking about.

From what I can see in your videos that looks like normal driving. It actually looks like you have a really well working tcc apply valve. The stock tune has the trans shift to the highest gear as soon as possible and once in overdrive with the converter lock they don't like to shift back down without a good amount of throttle usually above 30%.That's why the boost starts to come in because your putting a load on the motor.

and you think this happened all of a sudden? I bet my car would react the same way (minus the boost)

yeah because it didn't do it before and i couldn't get the rpm past 4000k before i change my spark plugs ether but now i can as you can see in video #21 almost to the end when i hit the gas. But this is my first 3.8 supercharger i guess what I've been talking about is normal.

The park rev limiter is at 4k rpm, so it won't go over that just in park btw. If you were in drive and it wouldn't go above 4k, could be an issue like a clogged cat.

Also when you say it didn't do that before, you may have payed attention to it when it was cold, the torque converter will not lock when trans temps are below 70°.

one more thing i recently changed my radiator and lost a lot of trans fluid like 2qt but only put 1qt back in would that have a affect to