I have a 2006 Chevrolet Silverado 4wd 5.3. Truck is mostly stock other than I have regeared it from 3.42-3.73 and upsized to 33” tires. I had the speedometer recalibrated after this. I just finished installing the Performabuilt heavy hauler 4l60e with the provided FTI 1600 stall converter. I have read a lot of good feedback and personally seems like a nice built unit from what I have researched. I have a new throttle body less than a year old and I had my local mechanic reset all the adaptive tables with his snap-on diagnostic tool. The issue I have is at light to moderate throttle the transmission shift abruptly and clunks when shifting from 2nd-3rd. 1-2 and 3-4 are nice and firm with a good progressive shift. Also it seems to shift out a little early in my opinion. I am aware of the clunk bulletin that gm put out for the oem transmission. My old one would only clunk at certain times but the new performabuilt does it like clockwork. If I drive it the same way but in tow haul mode it seem to be all but gone. Is there something I could check or any tuning that could help improve this condition? Thank


s

 

Did you contact Performabuilt? They are really easy to work with.....

 

Have you contacted Performabuilt yet about your concern?

The shift can be adjusted in the tune so it doesn't shift early as you put it. I can be adjusted to shift later in the RPM / MPH / TPS to fit better to your liking.

 

I did contact them and they said to check and verify the pressure settings where set to default and see if the adaptive pull back was set at -.3 which gm sets it at to drop the pressure on the shift from 2nd to 3rd. Far I know the truck has never been tuned I bought it with 100k miles now has 165k. Just hoping there was something else to check as I don’t have anything to check these settings or tune settings. Don’t know if I uploaded a video if that would help any?

 

Find someone in your area that does tuning to have them look at it.
The only person I know of in Alabama is Richard at Atomic Fabrication and Performance. He does tuning and he would be able to look at it.

 

You may have answered your own question. Have your tuner to set the adaptive to match tow hall mode in regular mode, But bear in mind the 2-3 will never feel the same as the 1-2 and 3-4 as what is happening is totally different, The 1-2 and 3-4 with these two shift you are simply applying a component, The 2-3 however is quiet different it involves releasing the band while applying the 3rd clutch depending on conditions you will either have one release momentary neutral followed by apply or an overlap as one come on and on turns off, It will not feel the same and does not even on my own car at some throttle positions it feel a bit like someone bumped me in the rear lightly. GM got around this to some extent by pulling the line way back during the shift. I did not like that so chose not to do it in my tune i just accept the different feel of that gear swap.
The heavy hauler is built to be less aggressive than the performance units but still has a wide band and corvette servo along with larger feeds for 3rd in particular as it is the 60e weakest gear set,
It will not feel like stock as its primary purpose is to apply firmly and limit clutch slip which is how you get a smooth shift as much as possible without being to aggressive. In this mode there is also a compromise as with everything heavy duty or performance.
Frank

 

Thanks 1FastBrick for the lead Atomic Performance is in Huntsville Al where I work. I will see about getting some tuning done and see how that does. Thanks Frank for the quick response and information. I will shout back when I get done!

 

Your welcome!

 

If PerformaBuilt uses the Sonnax HD 2-3 shift valve on this unit. Then the clunks will be more pronounced as in the 700R4, which has the overruns applied on the 1st, 2nd, & 3rd shift when in Overdrive. I do not know if they have modified the steel cover on the Corvette servo with the 4 notches for oil entry and exit. I have found that doing this modification helps with the clunks somewhat. As for Torque Management. I have seen from customers stories that a 50% reduction seems to work well with the shift feel and having durability at the same time. Having little to none of TM will give the firmest shifts at part throttle. I am not questioning the build here. I am giving you my experience on this.

 

I did the four notches on the 2nd gear servo on my previous transmission and it did help the 3-2 downshift clunk for sure but not sure what Performabuilt does. But when you say reducing torque management to 50% does that help smooth the shifts up of make them more firm?

 

The HD 2-3 Shift valve does NOT apply the overruns when in OD shifter position.
It applies them for 1-2-3 anytime the shifter is in D3 position
HD 2-3 shift valve will have no affect on anything when in OD shifter position.

 

Correct! I'm sure PBA just mistyped when he included "Overdrive".