cjg454ss

iTrader: (27)

i had a converter shudder with my 07 yukon, 70k miles on it. it was slight and then started to get worse when towing over the past month, called GM dealer and they said it needs a new converter but with the turbo the waranty wont cover it. $1400.00 to have them do it.

here is what i did

flushed the transmission with mobil 1 synthetic tranmission fluid, added a bottle of positrac friction modifyer,

i drove the suv 1000 miles so far and no shudder, previously it was bad enough to hear the vibration.

hope this helps you guys

nonnieselman

iTrader: (10)

Hum... never would have thought of that. wonder what the FM will do to the pump and such over time?

03sierraslt

iTrader: (22)

Interesting.

Gadgetized

iTrader: (9)

Keep us updated on this. I would think it is going to start back up again. The shutter is the clutch in the converter slipping. The damage has already been done. In reading pressure in the tune might help it.

cjg454ss

iTrader: (27)

it does not mean the converter is toast, i spoke with a few 4l60e converter guys and they said the clutches get dirt on them, like a film and a full flush and some additive will fix it, i actually tried this on my brothers tahoe, 07 also, his shudder is gone and that was in february of this year, he has about 15k miles on his since doing it, but his suv is 100% stock also.

chevrolet all the way

iTrader: (24)

4l60e has a pwm clutch. pulse width modulated. therefore its very rare you have a full apply inside. when he feels the shudder is during the slipping of partial apply. a "glaze" can build up on the clutch causing a shudder from an inconsistent apply. thats why the modifier can cause it to go away and can actually keep it away. it most likely wont cause any other damage to the trans. there is some stuff called shudder fix i have used for years on problem transmissions for cheap car lots.

1989k1500

iTrader: (23)

I always turn the PWM off in the tune and dont get the shudder.

1FastBrick

iTrader: (17)

Do you use the shutter fix from lube guard???

cjg454ss

iTrader: (27)

where is hp tuners is pwr? to turn it off?

chevrolet all the way

iTrader: (24)

you talking about this stuff? yes!