I found the following information about my 1982 transmission:

Type: 3-Speed Automatic Hydraulic Torque Converter & Compound Planetary Gear System - "700-R4"
Gear Ratios:
R: 2.29
D: .70
3: 1.00
2: 1.63
1: 3.06

In reality there are 5 total forward gears (I counted them). Why is it called a 3-Speed? You must forgive me. Although I am 32 years old, I have never been brave enough until now to purchase a car with an auto tranny, and know nothing about them (other than to make sure before you buy that it doesn't "bang" into gear).

 

I'm not sure where you got that information, but the 700R4 is a four speed transmission. Any extra "shifts" that you are feeling are the converter locking up.

 

But it shifts reliably at the same points under a constant acceleration:

1st 0-10 mph,
2nd 10-25 mph,
3rd 25-33 mph,
4th 33-42 mph,
Overdrive 42-52 mph

 

I am not sure why they call it a 3 speed. I have always heard it called a 4 speed, even its replacements are called 4 speeds. I think what you counted was the 5 shift points, 4 gears and 1 torque converter lockup. The 700R4 in the 82 vette was the first and the weakest of them all. They progressivley got better as GM did improvements.

 

When I first bought an 86 IROC with the TPI/700R4 tranny combo, I was pretty confused as what gear I was usually in because the converter lock-up in fourth gear made it feel like another gear was present. You definitely have a 4 speed with lock-up torque converter in fourth gear which makes it feel like you are shifting to a fifth gear.

Be glad, your car came with a tranny that many are trying to upgrade into their cars from the TH-350 original.

Most 82s have gone over the 60K mile mark and this seems to be the area where the 700R4 would self destruct. Check your car out to see if you can find any hint that the tranny was replaced, such as writing or bolts that look like they have been wrenched on more than once. If your lucky, the tranny has been replaced with a post 1987 tranny or rebuilt with better components.

Mine was replaced in 1991.

Brent...

 

The 82 tranny will lock up in all 4 gears. thats why your feeling so many different RPM points. and the tranny is pretty good, it was the plastic front pump that was weak. have a tranny shop tell you if yours has been updated to a metal pump.

 

Try your constant acceleration test again but this time with the brakes slightly on. There should be a switch on the brake pedal that cuts the +12V to the tranny when braking, thus preventing torque converter lockup, so all you'll feel is the shift points & not the converter locking up.
:cheers:

 

I have definitely checked it all out several times, and there are 4 distinct shifts into 5 distinct gears - all at the same points under the same acceleration. I say "gears" because the car does not just feel like it shifted, but actually goes into a gear - the rpms drop down slightly and everything. I can even hang out at that speed and the rpms stay the same - and the car is always smooth.

I went and had a transmission service done yesterday afternoon (just to get new fluid in there). I tested it all several times this morning and it feels the same - 5 total gears and very smooth...

 

there are 4 gears, the 4 IS overdrive. The fifth gear you feel is the torque converter locking up. It only will do that at steady pspeed/throttle position. When youy tap the gas it will jump out back into 4th or whatever geatr you are running. Normally the TCC can lock up in all lower gears except 1 with an aftermarket prom or one of the toher " tricks" you can have it lock up only in 4th. FI so you will feel 4 gears. if it can lock up in all lower gears you could feel 7 gears.

 

Trust us. We know what we're talking about. :yesnod:

There is NO POSSIBILITY WHATSOEVER you have 5-speed automatic in your car. Not even the latest-model Corvettes have 5-speed autos!

 

The only 5 speed auto's I have ever seen, one that Ford makes and is available in some of their vehicles as an option, and I also saw one in the Cadillac CTS web page. Both of these are labeled 5 speed automatics in the sales brochures, but wheather it is actually a 4 speed with TC lockup, not sure. But they do call it a "5 speed auto". To my knowledge GM has NEVER called the 700r4, 200r4, 4L60E, or 4L80E a "5 speed auto.

 

Also, the TC lockup will not function until the car is warmed up. Don't know if the early TH-700s did this but if you tap the brake pedal while cruising, the TC will briefly unlockand then lock again.

Honda also makes a 5 speed auto.

 

yup, early TCC's also unlock w/ brakes. TCC unlocks with brakes, gas, moving the shifter... everything that's not steady cruise will stop TCC.

Yes, TCC only works in closed loop mopde (unless you have a manual switch of course)

 

A 700R4 has never been referred to as a 3 speed transmission. your description "3-Speed Automatic Hydraulic Torque Converter & Compound Planetary Gear Syste" is what came in the 81 and was the TH350C (lockup convertor) the TH700-R4 is a 4 speed automatic - always has been and always will be.

Gear Ratios:
Reverse: 2.29
OverDrive: .70
3rd gear: 1.00
2nd gear: 1.63
1st gear: 3.06

These numbers are correct and as you can see there are four (4) forward gears. As to what you feel, rest assured you are mistaking trans convertor lockup for another gear selection.

 

The "information" came from here: http://corvetteactioncenter.com/spec...82chassis.html

Maybe someone should tell them their info is wrong.

Riddle me this: If I am feeling the TC "lock", can someone tell me if this is bad? The transmission works just fine. When I think of the word "lock", I imagine some kind of failure or at least a hesitation, and bank, or jerking motion. I don't have any of that. Can someone define the characteristics of a tc "lockup" for me?

The inventor of the automatic transmission was an idiot, and no one seems concerned with perfecting this purported "technology". Only a human body knows when to shift... That was the only thing I had concerns about buying an '82.

 

When a converter locks up, it feels like a shift. Read the info at the following link to find out a little about the workings of a converter- http://auto.howstuffworks.com/torque-converter.htm

 

Its GOOD!!!! A torque converer will always slip slightly & this will cause heat build up (the main killer of auto trannys). It's also saps power. What a locking torque converter does is literally what it says - it locks up, so the engine is effectively directly coupled to the driveshaft (in the same way as a manual gearbox does). This stops the extra heat build up (a good thing, esp with OD), gives better fuel economy & lets the motor turn at lower rpms at the same road speed.
A simple way to imagine it is that there is a clutch plate inside the torque converter. Normally the 2 parts of the converter (I'll call them "driven" & "driving") are mechanically separate & the fluid pressure tries to keep the driven part turning at the same speed as the driving part, which can never happen. When lockup occurs, fluid under pressure is diverted by the TCC solenoid (sort of!) to force the clutch plate to engage, which locks the 2 parts together, in the same way a normal clutch works, & the driven part will rotate at the same speed as the driving part. With just a fluid coupling you'd never be able to get the driven part to rotate as the same speed as the driving part. This is a very simple way to view it, but it works for me :D For a sensible description there's a good explanation on the Bowtie website.
In the '81 TH350C the lockup would drop the rpms by about 300, feeling like it's changed into a higher gear & I guess the 700 would be about the same. It's a great feature to have :yesnod:
:cheers:

 

Gosh, all I had was a simple question and I learned a whole lot more. I did the "slight brake pressure" thing, and sure enough, there was no shift into the phantom "4th gear" - there are just 3 shifts into the 4 gears. I'm just glad to find out it seems to be working properly. Thanks all!!!

 

Thats what were here for... :cheers:
Now get a picture of your car posted so we can see... :cool: