Sonnax4L60E Boost Valve and Spring Kit .490''

This fits as described

You do have to drop the pan. Pressure was increased. Shifting perfectly now. Was slow going into reverse. Now it's shifting like new again. This went into a rebuilt done by Bulldog? out of Atlanta who claimed to over build the tranny. I was a bit surprised they gave me back an older style to replace the newer style they received as a core. The booster in it was stock. The new one is NOT steel. BUT, it's working like a champ. Another Shop told my customer they needed a new rebuilt tranny for $4200. Just hooked it up to scanner and gave that diagnosis for low pressure. There was no debris in the pan or old filter. Everything was fine except for slow going into reverse in high range. New booster fixed the problem and now it's just like normal going into reverse and my customer was tickled not having to shell out all that dough.

I ordered this kit with the Sonnax super hold 2nd and 4th servos. This was installed in a Caprice wagon with about 80k miles on the transmission. I installed them all at the same time, so I don't know how much of the improvement came from each of these parts. The shift improvement was noticeable to me, but definitely not harsh. My wife did not seem to notice or at least did not complain. So if you're looking for neck snapping shifts from your 4L60, you will need to do more than just these 3 parts.In vehicle installation was pretty simple. It is pretty easily accessed by dropping the pan. Should be easily accomplished by most home mechanics.

This is a great HD boost valve. Highly recommended.If you're eyeing this item, you likely understand the hydraulic circuit you're playing with here. This brings a positive engagement, and provides the proper on-demand line pressure that I was looking for without going to the .500 valve.I have had a few people complain, commenting on "harsh shift" where as, it seems perfectly reasonable in terms of shift feel to me. The shifts are no longer the stock laziness, and are nice and short at WOT.

Thank You

Installed this, along with a Sonnax 1-2 accumulator, during a fluid and filter change. Took me longer to find my snap ring pliers than to do the whole job. No more hesitation going into reverse, and overall shifting feels a lot cleaner. Would definitely recommend to anyone.

I like Sonnax's boost valve because mainly because it gives the increased pressure when it is needed, when RPM and/or throttle are increased. During normal driving it allows normal pressure which causes less wear in the pump and makes a more efficient transmission. Many other kits just change the spring which makes for extreme pressure all day every day...this actually increases wear on several components. Sonnax obviously spends a lot of time and money making improved parts to offer us.Thanks Sonnax,Jeff LaneyInternational Automotive Resources LLC

I k how I gave it a 5 star. I was not able to use it because the reconditioned valve body I received had the larger valve. But I have used this brand valve in another transmission and it worked great.