GTP transmission the same?
Staging Lane
Joined: Nov 2010
Posts: 85
Likes: 0
From: Carol Stream, IL
I'm sure this has been covered before but I couldn't find it in my searching, that is why do the GTP and other Supercharged 3800 folks seem to not have as much trouble with their transmissions as the LS4-folk?? I mean it's not like the SC3800's are low on torque, especially after a few mods. It seems weird...
The L67 cars have about 40 lb-ft of torque less than do our LS4s out of the box.
Also, the LS4's version of the 4T65-HD has different valve body calibration that is biased towards smoothness in the name comfort as well as supposedly enhancing durability. At least, on paper.
As it turns out the execution of those upgrades turned out to be substandard, and as a result, we get grenading torque converters and leaking seals.
The interesting thing is, the LS4 gear train and axles are stronger than those found in the SC3800's trans. And those items are never the cause of failure. It's usually the converter relief valve or an internal seal that puts an LS4 in the shop.
Also, the LS4's version of the 4T65-HD has different valve body calibration that is biased towards smoothness in the name comfort as well as supposedly enhancing durability. At least, on paper.
As it turns out the execution of those upgrades turned out to be substandard, and as a result, we get grenading torque converters and leaking seals.
The interesting thing is, the LS4 gear train and axles are stronger than those found in the SC3800's trans. And those items are never the cause of failure. It's usually the converter relief valve or an internal seal that puts an LS4 in the shop.
Staging Lane
Joined: Nov 2010
Posts: 85
Likes: 0
From: Carol Stream, IL
So to that end I must ask, is our TQ Convertor relief valve different than that of the Regular (GTP-version) of the 4T65-E? And is there anything, besides regular trans services, that can prevent the relief valve from failing? i.e. TCM reprogramming/shift kits, etc?
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Not sure what the part interchange on the converter relief valve, but the recommended one is made by Sonnax costs about $4.95. The problem is, the you need to drop the cradle and pull the trans down to access it.
If your trans is still in good shape and not exhibiting any weird behavior, AND there's no material in the pan, then it may be worth the $300-$400 in labor (if you don't do it yourself) to have the valve replaced with the Sonnax unit. This is the route I went, though I also upgraded the valve body, seals, and had some clearance taken out of the 2-3 clutch pack.
I have a couple of threads that describe the whole cause and effect, as well as what I did to upgrade. You may want to check them out.
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Joined: Dec 2005
Posts: 2,932
Likes: 12
From: CT
and no... even the LS4 gxp and monte/impala ls4 trannies are different... due to the tap-shift...
the ls4 gxp tranny is not the same as the monte/impala ls4 tranny...
there are different internals...
the ls4 gxp tranny is not the same as the monte/impala ls4 tranny...
there are different internals...
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
