Question about Transgo HD2 kit in C5
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Question about Transgo HD2 kit in C5 Don't want to steal someone else's thread, so I thought I'd start a new one.
I'd like to install the Transgo HD2 kit in my C5 4L60E. After crawling under the car, I can see that it's not possible to access the 2-4 Servo without dropping the trans some. Is it possible to drop the cradle and transmission enough to access the servo without actually taking the trans out of the car?
If that's not possible, will the kit still improve longevity if the 2-4 Servo parts aren't installed until the whole trans needs upgraded?
I'd like to install the Transgo HD2 kit in my C5 4L60E. After crawling under the car, I can see that it's not possible to access the 2-4 Servo without dropping the trans some. Is it possible to drop the cradle and transmission enough to access the servo without actually taking the trans out of the car?
If that's not possible, will the kit still improve longevity if the 2-4 Servo parts aren't installed until the whole trans needs upgraded?
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The only thing the HD2 kit does to the servo is install an additional cushion spring in the 2nd gear servo. Perhaps an expert like Clinebarger can confirm, but I suspect it prevents the band from having an excessively firm engagement (slam) during the 1-2 shift.
I therefore think that installing the HD2 kit is fine without the servo mod. I would then drill the 1-2 shift hole to the lower .082 value. Take PBA's advice and don't install any washers into the 1-2 accumulator. While some people think that super firm shifts are cool, they are the equivalent to taking a sledge hammer to the internals of your trans.
If you are not quite ready for the Transgo HD2 kit, just install the Sonnax 4L60-LB1 boost valve for now; it is actually better than the Transgo Boost valve because its o-rings prevent leaks around the valve. This will increase your line pressure a bit across the board and increase the max line pressure at WOT. I recommend the Sonnax boost valve even if you are installing the full HD2 kit.
I therefore think that installing the HD2 kit is fine without the servo mod. I would then drill the 1-2 shift hole to the lower .082 value. Take PBA's advice and don't install any washers into the 1-2 accumulator. While some people think that super firm shifts are cool, they are the equivalent to taking a sledge hammer to the internals of your trans.
If you are not quite ready for the Transgo HD2 kit, just install the Sonnax 4L60-LB1 boost valve for now; it is actually better than the Transgo Boost valve because its o-rings prevent leaks around the valve. This will increase your line pressure a bit across the board and increase the max line pressure at WOT. I recommend the Sonnax boost valve even if you are installing the full HD2 kit.
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Thank you sir! I do appreciate your reply and I am going to the the HD2 kit with the Sonnax part you recommend.
My car is an 04 C5 and Summit Racing is showing the Sonnax 4L60-LB2 boost valve for 01 through 04 transmissions (late style pump). Summit shows the Sonnax 4L60-LB1 boost valve for 94 through 2000 transmissions (early style pump). The Sonnax WEB Site just lists the LB1 for early pumps and the LB2 for late style pumps without showing any year models that might have early or late pumps. I could order both and return the part that doesn't fit but I'd rather not go that route unless I have to. Any thoughts on which is correct - the LB1 or the LB2?
My car is an 04 C5 and Summit Racing is showing the Sonnax 4L60-LB2 boost valve for 01 through 04 transmissions (late style pump). Summit shows the Sonnax 4L60-LB1 boost valve for 94 through 2000 transmissions (early style pump). The Sonnax WEB Site just lists the LB1 for early pumps and the LB2 for late style pumps without showing any year models that might have early or late pumps. I could order both and return the part that doesn't fit but I'd rather not go that route unless I have to. Any thoughts on which is correct - the LB1 or the LB2?
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Starting around '05 GM introduced the ISS (Input Speed Sensor) version of the 4L60E; this has the new-style pump and requires the -LB2 which is the shorter boost valve. (If you install the Transgo boost valve, leave off the thick washer.)
I could be wrong and perhaps some 4L60E before '05 have the new-style pump (but definitely not back to 2000).
Look at the Sonnax instructions:
http://www.sonnax.com/parts/2168#tabs1-instructions
Notice that the new style pump has a square cut-out where the boost valve is. When you drop the pan, you should be able to tell what you have.
Go ahead and order both, and return what you don't need. Go by the Sonnax instructions, not whatever is on the Summit website.
I could be wrong and perhaps some 4L60E before '05 have the new-style pump (but definitely not back to 2000).
Look at the Sonnax instructions:
http://www.sonnax.com/parts/2168#tabs1-instructions
Notice that the new style pump has a square cut-out where the boost valve is. When you drop the pan, you should be able to tell what you have.
Go ahead and order both, and return what you don't need. Go by the Sonnax instructions, not whatever is on the Summit website.
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I did some testing on the TransGo .500" boost valve versus the Sonnax .490" boost valve w/O-rings in a vehicle years ago. The pressure difference was apx. 2-4 pounds and this is negligible. The O-rings help a lot when air testing, but make little difference in "real world situations". Sometimes the TransGo boost valve is a little loose as far as clearances. I would Tell TransGo about this if you have a "loose" boost valve and request a "new" boost valve from them if you have a problem. This will help TransGo to "fix" the problem, if they are made aware of it. If you do all of the Shift kit modifications and anything else and the transmission is not shifting quick at WOT, you should put a pressure gauge on it to make sure that you have the right WOT pressure, 235-245 psi. maximum at WOT. Sometimes the EPC solenoid needs a "minor" adjustment to get the right pressure. Most of the time with either Sonnax or TransGo the pressures are fairly close. When installing the boost valve with O-rings, make sure the bore is very smooth, so as to not "cut" the O-rings. Use lube on the bore and O-rings to keep from cutting the O-rings.
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Thank you for the information on the boost valve, I'll be careful with it. The trans has 53K on it and is shifting really well. My tuner has it shifting crisply at any speed and never any that are too hard, up or down. I want to preserve the unit as long as possible, hence the shift kit. I just hope the kit doesn't diminish current shift quality.
I have a new Transgo separator plate coming along with the Sonnax HD 2-3 shift valve, Sonnax TCC regulator valve and Sonnax 77754-R2 Reamer Tool. Also have assorted springs, filters, trans gel and gaskets from various sources. I think that should cover what I can install without removing the trans and give the longest life. Feel free to offer any suggestions or anything I might have missed.
I have a new Transgo separator plate coming along with the Sonnax HD 2-3 shift valve, Sonnax TCC regulator valve and Sonnax 77754-R2 Reamer Tool. Also have assorted springs, filters, trans gel and gaskets from various sources. I think that should cover what I can install without removing the trans and give the longest life. Feel free to offer any suggestions or anything I might have missed.
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Sonnax kit a success! I put the Sonnax Performance Pack in over the weekend. Took it apart on Saturday and put it back together again on Sunday. I was a little nervous taking the test drive - sure didn't want to take things back apart if something was wrong - but it shifted great! Everything works as advertised. WOT shifts are quick and firm, normal driving shifts are still quick but barely noticeable. I think I'm going to like this beast!