Trans problem????

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11-09-2009, 09:55 AM
yanoZ28

Trans problem????

I dunno if ne one has had this happen to them before, but anyways....
My camaro is an A4 and lately, if ive gone WOT in OD, the trans wont downshift sometimes, but instead just "accelerate" in the current gear. especially around 30-35mph. It obviously (or at least to me) doesnt do this in just regural "D" but just OD.
I checked all fluids, ran some trans honey through it... just have no idea why. The damn this just doest it when it feels like it. NE ideas or help???
11-09-2009, 03:23 PM
JaycenK

more than likley it is nothing in the trans but input sensors on the motor that are getting old and not showing the computer the varibles it want to see in order tell the trans to down shift. It could be weak pressure but it is more than likley a sensor.
The 4l60e shifts based on throtle possition sensor, manifold absolute pressure sensor, Mass air flow sensor, engine rpm, speed sensor and I'm sure there are a few more I missed.
11-09-2009, 03:35 PM
yanoZ28

Yeah Im wondering if this could be collateral damage from bending a pushrod and valve. Took care of that bout 500 miles ago
11-09-2009, 03:50 PM
JaycenK

nah, just life of hard shifts.
11-10-2009, 09:44 AM
yanoZ28

Ill be damned, pulled out the MAF, and the screen was damaged and some nest-looking thing was wedged in there....odd, maybe my prob. No worries though, i was thinkin of a new 85mm slp one ne wayz. Now im just gotta pull out the old trusty haynes manual and start sensor hunting. :brick:
thnx for the help
11-10-2009, 05:53 PM
pajeff02

Quote:

Originally Posted by yanoZ28

Ill be damned, pulled out the MAF, and the screen was damaged and some nest-looking thing was wedged in there....odd, maybe my prob. No worries though, i was thinkin of a new 85mm slp one ne wayz. Now im just gotta pull out the old trusty haynes manual and start sensor hunting. :brick:
thnx for the help

Best bet -- leave the MAF alone. If yours is damaged such that the screen can not be re-installed, get a stock GM replacement. Aftermarket MAFs do your car no favors and actually lean out the A/F. You can go up to about 500 hp with the stocker before it becomes a restriction.

Interestingly, if you purchase a MAF from GM Parts Direct, they now send an 85 mm unit with an adapter harness. I replaced ours as the stock MAF had been de-screened, de-bladed and hacked up. The car had an off idle stumble that disappeared once the MAF was replaced: http://www.ls1.com/forums/showthread.php?t=113122
11-13-2009, 09:59 AM
yanoZ28

Quote:

Originally Posted by pajeff02

Best bet -- leave the MAF alone. If yours is damaged such that the screen can not be re-installed, get a stock GM replacement. Aftermarket MAFs do your car no favors and actually lean out the A/F. You can go up to about 500 hp with the stocker before it becomes a restriction.

Interestingly, if you purchase a MAF from GM Parts Direct, they now send an 85 mm unit with an adapter harness. I replaced ours as the stock MAF had been de-screened, de-bladed and hacked up. The car had an off idle stumble that disappeared once the MAF was replaced: http://www.ls1.com/forums/showthread.php?t=113122

Interesting, hows the flow on the new GM MAF?
11-13-2009, 10:03 AM
pajeff02

Quote:

Originally Posted by yanoZ28

Interesting, hows the flow on the new GM MAF?

I have no way to measure the flow difference -- stock is 78mm and the replacement is 85mm (if I measured correctly). At the time I ordered, I verified the P/N through GM Parts Direct. I did this again after I opened the box and found something quite different than I was expecting.

From data logging the car, I am not seeing any timing pulled except under WOT. I attribute this to the crap that we call gas in my area. No other evidence of a lean condition and the engine revs smoothly without any hesitation.