This old IROC gives me more problems than a girlfriend....

The trans is new rebuild, about 4 months old. Never has been quite right; but the old one was fantastic. This one likes to get a little skiddish around 1500 rpm in 3rd, but only when it feels like it should be getting into 2nd. If I'm barely on the gas, and the trans "should" go down, the tach bounces up and down (about 500 rpm), and you can feel something that just isn't right. Across all gears, the trans is slow to downshift; there is a noticable lull and it requires more pedal to get the downshift. The TV cable is adjusted as correct as I know how to do it, at least on the engine end. And I think my old trannie had a vette servo in it, that now is mysteriously gone.

** Edit - This isn't just in 3rd gear, as I was concerned about. I was just out and the same thing happens between 4-3. As far as 2-1 goes, I dunno, haven't tried to make the car do that yet. **

Seeing as how I'm an idiot about trannies, how about anyone out there who isn't? Who knows the most about 700r? If you're that person, how bout some help...what should I be doing or asking to diagnose this problem.

I love this car, but it's a bit of a headache. And GM won't do my seatbelt recall so, the cons keep stacking up. I guess the big pro- is outrunning the ricers and some ponies now and again.



HELP!!!!!!!!!!!!!

 

Sounds like you may have a torque converter lockup problem. Assuming you know what TCC engagement feels like....do you feel the converter lockup immediately after it shifts into 2nd gear?

A converter stuck in lockup will cause normal performance in first gear, but all gears past, the pedal will feel heavy, the motor will feel a little bogged, sudden throttle changes will produce sharp kicks, and reaching low rpms in a gear will cause some nasty bucking as you described, as well as occasionally some really bad noises.

Your converter SHOULDN'T be locking up until you get closer to 40 mph or so.....

Also, when cruising at higher speeds (45+ mph) , try tapping the brakes. Not really hard enough to produce any real drag, but enough to light the brake lights. You should feel the converter disengage. If you don't, and it's displaying the symptoms I mentioned above, sounds like the TCC (Torque Converter Clutch) solenoid or something may be gone.

 

This is the 2nd torque converter put in since the rebuild. The first one put in "apparently" was bad out of the box. I think I got taken by someone.....

They put in a Dacco converter, and *** knows what kind of rebuild kit. When I was 600 miles from home and my transmission went out, I took whatever put me back on the road. POS...

I do know one curious thing. My 700r4 seems like it has 5 gears. I say this knowing it only has 4, but there is something of a half-shift (RPM drop of 300-400) in fourth gear. In 2nd and 3rd, I don't know. I don't notice an extra pull or change when I'm going through 2-3. I do know that it's a lot harder to spin the tires these days, and the shifts are nowhere near as tight and smooth as they used to be.

I sure am glad they put a one year warranty on it, so I might go out and blow the **** out of it a couple weeks before it runs out.

I've even had other transmission "experts" drive this car since I
got back with it, and they say it works fine. I know differently, since I've had it before and after.

If I had a hydraulic lift, tranny jack, and engine hoist...I'd probab ly never deal with another mechanic again.


Thanks for the reply, what should I do next?

 

Ok, that "half shift" you're feeling is your torque converter lockup. Sounds like your lockup is acting perfectly normal.

As far as the "lull", lack of wanting to downshift, and the lack of power/loose shifts....sounds kinda like low line pressure to me. Has the TV cable been doublechecked for proper adjustment? All I can think to do, not being much of a transmission man myself, is maybe add a bottle of Lucas Slipfix....or the name might be different...but it's Lucas's transmission additive. It's really, really good stuff...a tad pricey at maybe $8 for a bottle, but it's thick as honey and will boost the line pressure a TAD on its own, but it's really good at reducing clutch slippage. I'd say that if you put that bottle in, and it makes a noticeable difference...then you're looking at either improper line pressure, or clutch pack wear.

But like I said...I'm no expert. Just advising you the best I know how.

 

Thanks for the idea.

Is there any chance this could be due to TV springs, governor weights, or some piddly-**** adjustment that's an 1/8" out (aside from TV cable @ TB)? I ask because of some old threads I've read through, and because I don't know what parts were put into my car, let alone how well they were put in.

I'd like to get this gremlin out of the car before I think about putting a servo in.

If anyone has a winning lottery ticket out there that I can have part of for a lift and a few odds and ends....I'd be happy to accept it!

 

This is where I stop replying... I don't know tranny internals...I just know torque converters and the TV cable hookup...

Hopefully someone else will pick this up.