My 4L60E adventure trying to cure harsh 1-2 shift

[Thunderball]

2001 Chevy Silverado 1500 base model with 4.3L (all the power of a 4 cylinder with the gas mileage of a 8 cylinder).

I bought the truck from a family friend several years ago. The truck had about 75,000 miles. It had a harsh 1-2 shift. Not a slide bang, just harsh. All other shifts were fine. I replaced the fluid and filter. All my fluid changes were with Dexron VI. The fluid that came out looked ok and nothing unusual in the pan. Nothing really changed with shift feel.

At about 90,00 miles got tired of the harsh shift and replaced the 1-2 accumulator piston with the Sonnax kit. It was not needed because the factory one was fine and not broken. But since I went this far, I changed it anyway and also used the spring Sonnax said to use. 1 spring instead of 2. Shifting was no better or worse. I drove about 100 miles and had fluid on the shelf so drained it out and put new back in. No change. I put in 2 bottles of Lubegard red. Have driven about 200 miles since and not any change. Maybe a little smoother.

I never get a harsh shift at full throttle. It mostly happens at moderate throttle.

I also cleaned the MAF and replaced the TPS.

I suppose I will learn to live with it or go to a professional. I’m just not sure I want to keep putting money in this old truck. It is not my daily driver.

Any thoughts?

 

[clinebarger]

Tighten the band clearance with a Sonnax extra long band apply pin, Remove the spring from the Accumulator Valve, And block the 4th Accumulator with a 1/4" checkball. You don't want accumulator valve modifications to affect the 3-4 shift.

Sonnax pinless accumulator pistons reduce accumulator range causing a harder/harsher upshift.

With a TransGo spacer plate & SK shift kit.....You can tailor/tune the 1-2 shift to your liking!

 

[Thunderball]

Tighten the band clearance with a Sonnax extra long band apply pin, Remove the spring from the Accumulator Valve, And block the 4th Accumulator with a 1/4" checkball. You don't want accumulator valve modifications to affect the 3-4 shift.

Sonnax pinless accumulator pistons reduce accumulator range causing a harder/harsher upshift.

With a TransGo spacer plate & SK shift kit.....You can tailor/tune the 1-2 shift to your liking!

Thanks for the quick reply. I do believe all that is beyond my capabilities, with the exception of putting in a stock accumulator housing, piston, and springs. If I want it fixed, I will have to find a local shop that is trustworthy.

 

[oldhp]

I don't know, so I'm asking. But can't you set shift pressure with a lap top since it's a "E" transmission???

 

[wlk]

I would give it more time as you only put 200 miles on it since the Lubegard Red. Lubegard fixed my 1st/2nd harsh shift but I took a little more time for it to be fully better, ~1000 miles.

 

[Thunderball]

I would give it more time as you only put 200 miles on it since the Lubegard Red. Lubegard fixed my 1st/2nd harsh shift but I took a little more time for it to be fully better, ~1000 miles.

I've put a little over 1000 miles on it since the 2x Lubegard red. Nothing much changed. So I drained out about a quart and put in a bottle of Lucas transmission fix. It is so thick that when the fluid is not warmed up, the 1-2 is less harsh, but when the fluid thins out it is back to the same. I suppose I will learn to live with it or go to a tranny shop.