TCC lock up in 1st gear??

[VIN7]

I understand that there is no fluid circuit that allows TCC l/u in 1st gear under normal conditions, but...

is it possible for the converter to stay locked all the time (including first) if oil is getting past the o-ring on the tip of the input shaft?

Mike

 

[theCATman]

What makes you think the converter is locking in 1st?

Is the engine killing when it's in gear & not moving/stopped? If not, then the converter isn't locked. If a TC is not unlocking, it'd be the same as holding the brake & releasing the clutch on a manual.... snuffed engine.

 

[SSedan64]

Damaged TC Clutch in Converter or TCC Apply Valve binding in Pump could cause unwanted lockup.

 

[VIN7]

Gotta on the stalling at idle, thanks for pointing that out. It's not killing the motor so I guess that rules that out.

Just got the car back together, 1.5 year old, 3000 mile 9x11 wouldn't lock up at WOT. At zero boost it would stall at 2500.

I sent it back to Bruce to see what was wrong and while it was opened up to loosen it up ~ 300 rpm. Clutch was replaced and restalled.

Just checking things out last night the rpms are lower vs road speed (various speeds/gears, part throttle) with the new converter, at 0-1lbs the converter stalls at 1950 rpm.

At wot with old converter 2-3 shift at 5000 rpm, drops to 4350 rpm

New converter 2-3 shift at 5000 rpm, drops to 4095 rpm.

Going to collect more data...

Mike

 

[theCATman]

It sounds as though it's locking up at WOT, correct? That's why it's dropping so many RPMS between shifts? It certainly shouldn't be doing that. WOT converter lockup is controlled in the chip & is usually only for racing purposes. No converter is supposed to lockup at WOT. Too hard on parts.

Here's a simple test to see if it's locking at all. Get cruising down the road at 55-60 MPH, keep your foot on the throttle lightly and tap the brake with your left foot & note if the RPMS jump up some (either by hearing it, or set your Scanmaster to RPMS & watch it). This will tell you if the converter is locking & unlocking properly under part throttle.

I'm no trans expert, but doesn't the Vehicle Speed Sensor (VSS) have something to do with the TC lockup? If so, maybe it's not working? I'm not sure, just a thought.

One thing I do know about converters though, is that just because they are rated at a certain stall speed doesn't mean it will stall to that number. It depends on the power the engine is making. A 3000 stall might very well stall at 3000 in a car making alot of power, but put that same converter in a less powerful car & it will not stall to 3000, it may only reach 2400.

 

[VIN7]

VSS is working and I'm using powerlogger, its just that after being on my back all weekend I just wanted to get in a shakedown. I logged the ride home and really didn't pay attention to any numbers until I sat down and reviewed the log.

I understand about the rated stalled ( I was referring to only 3000 miles on the old converter).

I have plenty of logs showing old converter stalling at 2400-2500 at 0lb boost, ~3000 at 5lbs.

I just expected that when it was loosed up the stall would have increased instead of decreased

But like I said, this weekend I'll do plenty of logging and get the data posted.

Thanks,
Mike

 

[theCATman]

My bad about the 3000:redface:

Here's a possibility... I think. The converter could actually be more efficient now than it was before, for your combo. It could very well be putting more power down and not letting it slip away like before. I understand what you're saying though. In theory, it should slip more now, but isn't.

Just a thought.