Jerk when accelerating from stop K2500 454 Suburban

[Mangonesailor]

Did you ever resolve this?

 

[rodek]

Hi, sorry for the delay

Yup! Had a problem in the 4l80e tranny.
Apparently it wears the bore of the Actuator feed limit valve in the transmission valve body.
This is a known issue in higher mileage trannies especially without oil changes.
This causes 2nd. gear starts which was the bump I felt when taking off.

So the tranny is in 2nd gear even though it is commanded into 1st. The worn bore lets fluid leak past and the idle revs doesn't supply enough fluid to overcome this, high mileage (160 00 in my case) pump makes the situation even worse. Now immediately when taking off the revs rise to 700 and up and the pump volume in enough to overcome the fluid leaking past the valve the transmission shifts to 1st. >>> BUMP

There is a cure from sonnax (Part No. 34200-16K) but I eneded up replacing the complete valve body.
There is a guy in ebay selling factory new VB's with really good prices, actually about 2x the price of the Sonnax part so got all new solenoids etc. for really nice price!

 

[Mangonesailor]

Gotta keep that one in the back of my head!

Thanks for the solution! Glad you're back on the road, sans clunkin!

 

[Austin Hammonds]

Did you happen to find the solution?!

 

[Mangonesailor]

Did you happen to find the solution?!

You can't possibly be seriously asking that when the answer is just a post above mine.

FFS, read the thread.

 

[rodek]