No overdrive?? 84 Berlinetta
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Joined: Aug 2021
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Car: 1984 Camaro Berlinetta
Engine: 350 sbc .60 over
Transmission: 700r4 2800-3000 Stall
Axle/Gears: 7.5" 28 spline axles. 3.42 gears
No overdrive?? 84 Berlinetta
So I don't know a ton about locking converters on how they work or how overdrive works in the 700r4. Here's my issue however. Normally I can count 5 distinct shifts when in D with overdrive. It will go 1234 and then the 5th one drops the idle down pretty low and would usually engage that at 35 to 40 mph. Now after driving about 250 miles in two weeks, some drag racing, and then having a lot of rain it started to not shift in to overdrive and would occasionally do it which I've noticed it do that before when the car is not up to temp. Now it just doesn't shift in to overdrive at all and I can only count 4 shifts. I don't know if I have a locking converter either. As far as I know the transmission is completely stock with 230,000 miles on it. I know it for sure needs to come out and be rebuilt and that will happen later on this year when I pull its motor out. Thanks a bunch!
Joined: Sep 2005
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Re: No overdrive?? 84 Berlinetta
There should be 4 shift "events" in a 700: 1-2, 2-3, 3-4, and TCC apply. AFAIK the TCC should apply only while in 3rd or 4th during normal driving, maybe only in 4th.
If you have a 700, it has a "locking converter".
The TCC (torque converter clutch) makes the engine –> wheels connection to become essentially metallic, almost like a manual trans. Once it locks up the engine RPMs should NEVER change unless road speed does, or unless the TCC drops out. That's a pretty easy way to figure out what's gone bad: either it's locked up butt doesn't shift into 4th (stays in 3rd), in which case, you have the invariant RPM behavior, butt the RPMs are high; or, it's in 4th butt the clutch isn't holding, in which case the RPMs can vary even when the road speed doesn't. Another easy way to tell is, if you're driving down the road and you tap the brakes with your left foot, the TCC should unlock, and the RPMs rise a bit; if that doesn't happen, then it's not locked in the first place.
Most likely, you'll find the TCC is the problem. 2nd and 4th both use the band, and if it was smoked, then it would have problems w 2nd as well as 4th. If 2nd is OK, then the band is OK, and 4th is most likely OK (although there are some other hydraulic differences), which leaves the TCC as the most likely perp.
If you have a 700, it has a "locking converter".
The TCC (torque converter clutch) makes the engine –> wheels connection to become essentially metallic, almost like a manual trans. Once it locks up the engine RPMs should NEVER change unless road speed does, or unless the TCC drops out. That's a pretty easy way to figure out what's gone bad: either it's locked up butt doesn't shift into 4th (stays in 3rd), in which case, you have the invariant RPM behavior, butt the RPMs are high; or, it's in 4th butt the clutch isn't holding, in which case the RPMs can vary even when the road speed doesn't. Another easy way to tell is, if you're driving down the road and you tap the brakes with your left foot, the TCC should unlock, and the RPMs rise a bit; if that doesn't happen, then it's not locked in the first place.
Most likely, you'll find the TCC is the problem. 2nd and 4th both use the band, and if it was smoked, then it would have problems w 2nd as well as 4th. If 2nd is OK, then the band is OK, and 4th is most likely OK (although there are some other hydraulic differences), which leaves the TCC as the most likely perp.
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