Bad speedo sensor and a shudder?

[94TAGT]

Ive had an ongoing issue with a shudder in my 94 TA for about 5 months now. The problem only becomes apparent when the speed is around 45-50 and the RPMs are between 1300-1400. When I accelerate the shudder goes away. Ive checked the bolts in the TC and all are still there. I've checked the normal engine mechanical issues..optispark,wires,plugs,icm,vac leak etc. and just cannot find anything. Over the past two years the engine and trans were rebuilt and up until last year there was no issue what-so-ever. Anyone have any ideas which direction I need to start? I was told a bad speedo sensor can cause symptoms similar to this.

[cahall]

Could be a lock up shudder. Best way to check is to get cruising to where it happens and lightly tap the brake pedal with your left foot, while not moving your right foot on the gas. If the shutter goes away, it
s most likely a lock up clutch. It will most likely come back when the converter locks up again. You can repeat this a few times to help confirm it.

A bad speed sensor won't cause anything like this. If a speed sensor is bad, the speedometer won't work and the transmission won't shift.

Frank

[94TAGT]

How about a bad tcc solenoid?

[cahall]

Originally Posted by 94TAGT

How about a bad tcc solenoid?

Not likely. I've never seen a TCC solenoid cause a shudder. It's a simple on/off solenoid. Either it will have lock up or not. Since yours is a '94, there's no chance it could be a PWM issue, either.
Was the converter replaced when the trans was rebuilt? A bad clutch in the converter is the most likely cause.

Frank

[94TAGT]

Yea the convertor was replaced when the trans and engine were rebuilt.

[cahall]

Originally Posted by 94TAGT

Yea the convertor was replaced when the trans and engine were rebuilt.

Just a stock generic converter? I've seen this quite a bit from shops that use cheap replacements. Dacco is notorious for it.

Frank

[94TAGT]

Oh no I put a tci in it. I know they arent the best but they're also not the worst I can think of.

[cahall]

Originally Posted by 94TAGT

Oh no I put a tci in it. I know they arent the best but they're also not the worst I can think of.

TCI lock up converters are lousy. That's where your problem is. Their clutches fail, and they're extremely inefficient.

Frank

[Dynamic396]

Couldn't agree more... Get a decent converter!

[cocobolo95]

So what brands make a decent stock type converter, and while your at it what brands of street performance converters do you recommend.

[cahall]

Originally Posted by cocobolo95

So what brands make a decent stock type converter, and while your at it what brands of street performance converters do you recommend.

I use/sell Protorque for everything. While they do make the best race converters, they also have a stock replacement line. A stock replacement converter for a 4L60E is $150. A converter with 1800-2500 stall is $300 (through me).

Frank

[cocobolo95]

I thank you.

[94TAGT]

So it appears that, right now, the convertor is fine. I will be looking into a Protorque replacement when time/money allows. The problem looks like it is actually a tuning issue with the convertor lock up setting.

[cahall]

Nothing to do with tuning will cause a shudder.

Frank

[94TAGT]

Aren't stall speeds tuned to match a power curve?