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2003 chevy trailblazer_ls
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I'm running one. Doesn't do so much on shifts, but rather, overall system pressure. It holds better once shifted. Of course, if the system pressures are increased, there will also be a slight change in shift quality also, but if that is your entire goal, you'll likely be a bit disapointed. A Corvette servo will give bigger gains in shift speed, especially the 1-2 shift that seems to lag so much on the 4L60E.

It is a good mod for the low bucks it costs, though. I'd do one the first time the pan is off for a filter change, as it takes no further dissasembly, except to pull the actual boost valve out of the front pump with a snap ring pliers.

What you'll need to accomplish the part swap is a GOOD long-nosed snap ring pliers of the correct size (the holes are about medium size -- consistent with any snap ring in the hardware store with about a 1/2-3/4" diameter -- if you want to size up the tool before you start), a smallish screwdriver (just in case you need to hold the valve in position while you get the snap ring in or out), a small light to see stuff, and sometimes a needle nose pliers helps.

Otherwise, it is very simple. Remove snap ring; remove old valve and spring; install spring on new valve; push back into bore; re-install snap ring. The valve is located in the front pump at the very front of the transmission case (directly inside the front edge of the gasket rail) and slightly to the left if you are laying under the transmission with your head toward the engine. It is up in its hole about 3/4" or so. The boost valve that comes out is just an aluminum plug with a small bump on it. Easy to see, easy to swap, except that once in a while you wish for another hand.

Do you have a tune yet? If not, spend the $100 or so needed for a PCM for Less tune. That is THE best modification for the TrailVoy for the money. There, you can specify the transmission shift level from 1-3. I have a 3 setting, and it is firm, but not nasty (not like my old B&M race kits!).

If you are looking for tire-squealing shifts, get a different vehicle. NEVER going to happen unless you have the SS and do some work.
 

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2003 chevy trailblazer_ls
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It is really very simple -- just drop the pan, locate the valve, remove the snap ring, pop out the old one, reinstall the new, and reinstall the snap ring. Replace filter and pan, fill with oil and drive it.

If you are reasonably qualified as a mechanic (in other words, you'll have no problems dropping the pan and have a decent set of snap ring piers) there is no reason that this job couldn't be finished in under an hour right on the driveway where you live. No further disassembly of the transmission is needed except to pull pan and filter.
 

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2003 gmc envoy_sle
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237 Posts
Are the boost valve and the accumulator piston in the same housing or is the pump separate from the piston? Thanks...

I'm just not sure if they go together...From the pics it looks seperate...but they fit together perfectly!
 

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2006 chevy trailblazer_lt
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314 Posts
yeah the boost valve..... too long.... the snap ring wont go in cuz the snap valve is just a hair too long. if you put the oe one next to the new one you can tell that its longer.... what a pain! that **** is not easy! its a headache! unless the car was upside down then and only then would it be easy!!


the spring... pretty easy along with the piston accumilator thing. what ever its called. if you take like a ice pick the pin in there should pop out easliy. dont sqweeze till you get all the oil out... i almost got sqwerted in the face. lol
 

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ps i did my install all morning. the corvette servo would be super easy... if there was enough room to work with. taking it to a muffler shop tomorrow to get the exhaust dropped. re.dic.cu.lous! not too happy with the results from the spring either.... not for 5 hrs of work
 

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2003 chevy trailblazer_ltz
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2 different boost valves for 4L60-E's. 1994-2004 are 1.907" long and the 2005+ are 1.810" long. You have a 2006 model trailblazer. You ordered or was sent the wrong boost valve.
Steve
 

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2005 chevy trailblazer_lt
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That's exactly what I did then. I couldn't get that boost valve past the snap right spot for nothing. It drove me crazy. Dang ... now I'm having problems with the servo. Snap ring keeps snapping off.....is the servo different for years of tb's? 16 quarts of tranny blood later. My boys been parked all weekend bleeding all over the place :sadcry:
 

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I thank you - even with your misguided attitude!

I read almost every post on here about the matter and this was the first I heard of the 2 different sizes.

Before I ordered I checked out Oregon Performance Transmission and they were recommended on several forums.

I went to their website and they only have 1 boost valve listed.
After I read your post, I emailed them;

Hi. I recently ordered some parts from you. The one item was SNX-77898E-3K SONNAX 4L60E REVERSE BOOST VALVE & SLEEVE (.490").
Now somebody is telling me there are 2 different sizes of those depending on the year of the transmission. I only saw 1 listed on your web page and no year specifics - just want to be sure it will fit before I open it. (when it gets here).
Thank You
Nelson


And they replied;

Hello,

It is the internal size that is different. The valve you have will fit into your transmission. This valve works in all 4L60E, 4L65E, & 4L70E.

Please let me know if you have any other questions.

Thank you,

Brian


And my asking you was also part of my research.
I'll be telling them the information from Sonnax that you supplied because evidently they don't know.
 

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2006 chevy trailblazer_lt
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Yeah I emailed them too no reply yet. There's no way that valve fits in there. Its a hair too long. I never got a reply but like was said they only have one size boost valve and just so happens to be the most expensive part of the bundle I orderd.... waaaahh:sadcry:
 

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Anyone figure out if they sell the shorter boost valve at that place??? I still can't find it.and now I'm stuck with a boost vavle that's just way too short.
 

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Oregon Performance does not sell it.
Try this:http://lmgtfy.com/?q=Sonnax+77898E-7K
:hopeless
lame. man im really starting to get annoyed. well i emailed them again and asked them what they can do for me to get me the right part. this is rediculous. if the part was like 3 bucks id just buy another one and trash the old one but 30 bucks... thats half a tank. lol
 
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