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Discussion Starter · #1 ·
2007 Silverado CCSB 4.8 and 4L65E

Have had the Corvette Servo and Billet 2-4 servo in for about 2 months now, seems to search a bit with part throttle.

Before it diddtn' seem to do this with the TCM line pressure increase from the tune.

I'm thinking about adding back some line pressure, for those of you with this mod - which helps holding on Highway and also wiht the 1-2 and all gear swaps, but don't like the part throttle searching.

Do you run the TCM tune on the tranny in addition to the servo swap?

Just looking to see as i'm considering adding back 10% pressure in all locations to the TCM.
 

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I did the Corvette servo on my 4L60e several months ago along with the 1-2 actuator. The actuator was for a TSB on "light throttle harsh 1-2 shift". I still feel the harsh shift on warm-up only, but I didn't do any kind of relearn. I did change the battery the other day and I don't recall how it shifted when I left work yesterday.

Seems, from your post, that you know a tad (meaning a lot) more about trannies than I do. How do you increase the line pressure?

I did not do a tune when I did the change.
 

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Discussion Starter · #3 ·
You increase line pressure to the TCM(Transmission Control MOdule) on Electronically controlled Transmissions. I have a Tuner which I have ECM and TCM abilities to adjust, before I did the Corvette and 2-4 Billet servo I had mine set to 15% and it made a huge difference. When I added the servo's, I removed all line pressure that was added in the TCM tune - and now it shifts firmer between gears, and it holds better on the highway in the upper gears and gets me better mileage, but it searches a bit in mid/part throttle - so I think I'm going to add line pressure back in mid/part throttle but leave the full throttle gear changes alone.

Does that make sense?
 

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Discussion Starter · #5 ·
Yes - you will need a tuner that has TCM control in it if you want to increase line pressure above and beyond what you did wiht your Corvette Servo, unless you do what I did and did the other servo as well - which was the Sonnax Billet 2-4, so my 1,2,3,4 servos are all aftermarket, even my cover on the side of the transmission is a pretty billet piece now.

But if you want to increase part throttle pressure or make changes without drilling on your tranny and/or shift kit - then TCM control that comes in some of the Higher end hand held tuners, or a custom tune is your only route:)
 

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Discussion Starter · #7 ·
Yes it will to a certain extent, but wiht my handheld I already reset everything:)

It's not really necessary though - however occasionally a reset of the adaptive learn system is not a bad thing to be honest:)

Nice 2014 and love the new stock Rims man:)
 

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With my 2006, I installed the Vette servo after a tune from Lewis. The 1-2 and 2-3 shift with part throttle hits pretty firm and I tend to like it. Before the 1-2 was soft, slow even with line pressure added. It does zero gear hunting.
 
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