Doug Hampton

The car in questions is 2002 Camaro ls1 with a 4l60. After thoroughly embarrassing a Datsun 350 something last night from a dig I got to the next light and shifted into first gear a stop. The light turned green and I started to lightly accelerate around the corner and the trans was jerking back and forth between first and second. I tried it again in front of my house and it did the same thing.

I'm stumped...Any thoughts?

Doug

mrvedit

Sorry, but more info would be helpful.
What does "shifted into first gear" mean? Did you manually shift into [D1]? Why?
In [D1] the trans should not be shifting between 1st and 2nd gear.

What happens when you start in [OD]?

If the car won't move in [OD], but will move if you manually start in [D1] and manually shift up the gears, this indicates a broken forward sprag.

clinebarger

If you were in D1, The bucking & jerking is normal if your on & off the gas pedal.

D1 is for emergency use ONLY.....To slow the car down.

Doug Hampton

I guess I could have described my issue better and now after driving for a few days I have a better handle on symptoms...

Once the transmission is hot and I have accelerated hard through a few gears or stomped on it hard causing it downshift at highway speeds it will all of a sudden start shifting really abruptly and really harshly. When I come to stop on the highway where I turn into my neighborhood I move the shift lever into 1st gear because I have a steep and windy S curve that drops into a small canyon with bridge with huge bumps on either end. Shifting into first allows me to navigate the curves and bumps without having brake, I have done it for years and don't think it is an issue except now after i womp on it hot it starts to shift harshly and when Shift to first gear it won't hold it, with steady thottle at less than 15% it starts jumping back and forth between first and second.... If I don't hammer it there does not seem to be a problem. Once it starts to act up I still have all gears.

Thoughts?

clinebarger

Have it scanned for codes.

Doug Hampton

So after driving it a little more the check engine light finally came on it set a p1870.

After a little research and talking with some friends I took the car to a local trans shop a friend knows and likes to discuss my issue with him. He was kind enough to take a ride with me and Snap On Solus scan tool to monitor torque converter slip. At 99 percent converter duty cycle giving it just a little gas you can induce 200-250 rpms of slip in the converter. He suggested that the tcc valve body passage was the culprit and could fix me up $250 in labor, $165 for a transgo kit plus fluid and filter. Seemed like a lot to me so I thanked him and brought the car home.

Last night I pulled the valve body and inspected the valve and bore. I could see no issue with either, no scoring everything seemed to move freely. Now I am thinking the converter is bad...

What do you think...Pull the trans and put a converter in it?

mrvedit

The PWM TCC valve is very prone to wear and then causes converter slippage and the 1870 code. The mechanic is probably correct.

One simple/cheap fix is to replace the PWM TCC valve with the Fitzall On/Off valve which has o-rings to eliminate leaks. The TCC will engage more firmly, but unless you are driving Ms Daisy, you might even like it better.

Alternatively I think a Sonnax rebuild valve body is available for around $275; it will have an oversize PWM valve and be ready to install.

PBA

The TransGo Shift kit will have the ISO-CONV valve (PWM eliminator valve). This valve uses other lands in the valve body bore that have not been worn by the original Iso-Conv valve. This will fix the problem (99% of the time) and keep the cost way down.

Doug Hampton

I have a Sonnax pressure regulator kit for the TCC Bore. Do you think this would solve my problem?

If not is The fitzall thing pictured what you are referring to?

Thanks!

clinebarger

He is talking about the PWM eliminator that comes in Trans-Go shift kits SK-4L60E & 4L60E-HD2, They work well even with a worn bore. Even though it does apply line pressure to the TCC clutch piston, And have had a few converter failures, However its a finger pointing game between TG & Converter builders. This is a FEW in hundreds of units with the TG Valve....

The Sonnax valve does regulate pressure & Eliminates PWM, But needs a bore that's in good shape, That is where their oversized Bushing & Valve kit comes into play, But the Reamer/Tool kit is expensive.

I have no experience with Fitzall products.

Doug Hampton

So I hate dead end threads and am happy to report I have finally solved the mystery.

I installed the Fitzall product mentioned early with no improvement. I then removed the transmission and installed a circle D converter and still no better. I finally took the car to a friend that works as a tech at a Chevy store.

What he found surprised me but his knowledge would have saved me a lot of un-necessary work. He air checked the tcc solenoid that is part of the transmission wiring harness and found the snout of the solenoid split along the casting of the plastic snout.

Hopefully someone someday will find this information useful. In all my digging I never found anything about a TCC solenoid snout being faulty.

Thank you for all the suggestions!

Best regards,

Doug

coryforsenate

iTrader: (1)

Thanks for reporting back! It's always good to hear that somebody solved their problem and added to the knowledge bank here.

mrvedit

Yes, thanks for the update. Sorry that my Fitzall suggestion did not work.
In the future I will mention that a bad TCC solenoid can also result in a 1870 code.