bbond105

I just purchased the Sonnax Pinless 1-2 and 3-4 Accumulator Piston Kit part number 77998-03K and the Forward Accumulator Piston Kit. I am not sure of what accumulator spring and how they should be installed in these locations. I have already installed the TransGo 4L60E-HD2 shift kit and they have the springs and pistons installed differently.

mrvedit

The Transgo HD2 springs will NOT work with the Sonnax pinless piston. You must use the stock springs or the special (unusual!) springs in the Sonnax Performance Pack.
I found the Sonnax setup a bit soft and therefore went with a stock aluminum piston and the HD2 springs.

For the 3-4 accumulator, I used the Pinless piston on top of the HD2 spring, exactly as the HD2 instructions show.

bbond105

Thanks for your info.
I don’t have the stock springs anymore and it been awhile since I have seen them. I was thinking that the Transgo HD2 1-2 springs are close to the same size as the stock springs? I’m not questioning what you are saying but why won’t they work.

I down loaded the instruction for the Sonnax Performance Pack and it says that if you use a ‘94-‘00 housing you don’t need the spacer. So it seems to me that if you use this housing the Transgo HD2 1-2 springs should work. May have to experiment to get the shift firmness right. The pistons won’t come in until Thursday so I am only guessing.

mrvedit

The stock and Transgo springs are completely different.
The stock springs consist of two springs, one inside the other, both underneath the piston. The Transgo setup consists of two half-springs, one on top and one below the piston.
The Pinless pistons are more like cylindrical instead of just flat. The lower Transgo spring is so short it fits almost entirely within the pinless piston. In other words there would be no spring action as the piston will bottom out before the spring compresses.
Once you get the pistons it will be obvious to you too.

There are at least two 1-2 accumulator housing styles; very late model (e.g. 2009) have less depth that earlier ones and therefore should have fewer spacers installed for the Transgo setup.

bbond105

Thanks mrvedit

I see what you’re saying. I saw in post on here somewhere where PBA said something about modifying the Sonnax Pinless Piston to where it can be used in the 1-2 accumulator with the Transgo springs. I wonder what he is doing to get them to work.

Would you happen to know which Sonnax spring I would need if I were to use this piston?

mrvedit

I don't know if/where the Sonnax performance pack springs are separately available.
It uses an inner and outer spring under the piston and a unique "waved" spring over the piston. I doubt that waved spring actually does much.

http://www.sonnax.com/parts/2928

I also don't have a good source for the stock springs, especially the inner spring. Various online sources sell stiffer 1-2 accumulator springs, but they are usually just a replacement for the stock outer spring which is then used with the stock inner spring.

bbond105

The Sonnax Pinless 1-2 piston came in for this weekend. I compared it to the stock piston to the Sonnax piston and found that if you grind the 4 tabs off of the top of the opening and ground a few washers to fit inside the piston the spring will have close to the same install height as you would using the springs from the TransGo 4L60E-HD2 shift kit and a stock piston.

mrvedit

Let us know how the custom mods work. If it doesn't work, at least it is easy to "fix".
I would recommend only one of the HD2 washers in the 1-2 accumulator.

bbond105

I hope to have it going again next weekend. I have a few more issues to work out. See my 2 other threads.

4L60E Forward Sprag Broke Again
4L60E Input Shaft Leaking

PBA

I use the Sonnax pinless setup for the forward accumulator. I use a "hardened pin" that are made in Germany (not China) and Rockwell 52 on the "C" scale for the thin pin 2nd accumulator housing. A file will not even scratch this pin. I use the aftermarket accumulator piston which has a much longer pin bore, than the stock piston. I machine off the 8 nubs when this piston is used with the over & under spring setup from the TransGo HD2 Shift kit. This does two things, a little more accumulation and less metal getting into the oil from the nubs not wearing well. I never use the spacers that come with the HD2 kit. The longer pin bore along with the hardened accumulator pin stops the pin and pin bore wear to a high degree, therefore less leaks in the circuit. With the regular TransGo Shift kit, I do not machine off the 8 nubs that are now required for release because it sits against the separator plate. The spring setup here is the same as the factory using the 2 or 3 spring setup from the TransGo Shift kit. You can use the Sonnax pinless setup here as the springs all sit on the same side. You can also use the Sonnax pinless setup on the 4th accumulator with either TransGo HD2 or the regular Shift kit. You "do not" need to install the steels check ***** on the 4th accumulator as you would be blocking a "blind hole" which does nothing. I add the TransGo .500 boost valve when using the regular TransGo Shift kit, and modify the separator plate hole sizes and change the accumulator spring rates for the 1-2 accumulator in the valve body to still get smooth part throttle shifts and quicker and firmer WOT shifts. The factory "thin pin" is not even available from GM, and is very soft. It's hardness is in the mid to upper 20's on the "C" scale. Without new pins not being available from GM means you only have used pins to choose from, or using the Sonnax setup. When using the HD2 setup for the 2nd accumulator the TransGo instructions are correct if you use the 428 accumulator housing. With the 937 accumulator housing, disregard the TransGo instructions and install the "blue spring" first, then the piston with seal and then the "orange spring". NO spring seat is used when using the 937 accumulator housing. This works best if you remove the 8 nubs on the accumulator piston for either accumulator housing. If you want the best shifts using the Corvette servo (this is with only using the HD2 Shift kit), use the "A" or "B" accumulator bushing from a 1993-94 4L60E, or from a 700R4. Easy to find in the 700R4's. Then use the "white" accumulator spring for the 1-2 accumulator bushing in the HD2 kit. With the stock diameter torque converter drill the separator plate to .076" - .082". Hole sizes larger than this will make the 1-2 part throttle shifts too firm. With the 10.5" - 9.5" diameter torque converter .093" - .099". The more aggressive the driver and or the higher the stall the larger feed holes are tolerated. I hope this helps out.

mrvedit

Wow, thanks for all the great info and "tricks". I know you have studied and tested all this for decades.
Very interesting info about using the older-style accumulator bushings; I will have to experiment with them now.
The info related to the different 2nd accumulator housings (428 versus 937) is especially useful. The 937 appears in later models, perhaps starting around '05.

bbond105

This is a lot of info to take in. Thanks for taking the time to share. I will have to check my notes as to what I have done and see what changes I need to make. Again thank you very much to the info. Like Ted says time to experiment.

I got the trans back in the car today but it didn't go too well. With the car still on the stands and the shifter in low it fells like it is binding up. Shift up to 2nd and it frees up, move the shifter to 3rd and no up shift. The same for 4th. The scanner shows that it is in 2nd gear and the shift solenoids stay in the configuration A off - B on in all shift lever positions. I will drop the pan tomorrow and check the pressure switch assemby with a meter. I think this is my problem.

This by far is not the first 4L60E I have built but it has been one of the most challenging. I just have to be patient and work it out.

TexasTandGranSport

Any chance you'd be willing to share with us which holes and how big you drill them to for different situations?

bbond105

Sorry it has taken so long for an update on the modified Sonnax Pinless piston in the 1-2 accumulator with the TransGo 4L60E-HD2 accumulator springs.

The 2-3 shift valve was stuck in the valve body causing it to bind in first gear and burn some clutches. After removing the valve body and freeing up the valve, the 1-2 shift didn’t feel right, most likely the burnt clutches. So out came the trans again. Since I had changed so many things on this rebuild, I decided it would be best to put it back to the stock 1-2 accumulator piston. It’s hard to evaluate a part when you change too many things at the same time.

This trans has fought me all the way. When installing the trans into the car some threads in the aluminum block striped out and I had to lower the engine out of the car some to repair the threads. Anyway got it all back together and trans is now working as it should. Next time I have the car up on jacks I will retry the Sonnax Pinless piston. At this time though I’m in no rush to do this, I think I’m going to ride for awhile.

mrvedit

Interesting (and sorry to hear) that a stuck 2-3 shift valve was causing you problems. Did you start a thread on the original problem?

Despite my many trans swaps (for experimentation) I have not damaged any threads in the engine block. However, I have damaged the bellhousing to oil pan threads. IMO, those two lower bolts should only be torqued to 25 ft/lbs, versus 35 ft/lbs for the bolts into the engine block.

I know very well how changing too many things at once can make the results confusing.
I made a bunch of "improvements" to my car last winter and it ended up slightly slower.

bbond105

The original problem was a broken sparg and the thread was.
4L60E Forward Sprag Broke Again
https://ls1tech.com/forums/automatic...oke-again.html

It’s all good for now and I’ll get back to the Sonnax piston again. I just need a break from it for a little while. The car was down for a month. When you live in a small town like I do and you need more trans parts on a weekend you are out of luck and that's why it took so long.

mrvedit

That is probably too general a question for anyone to answer as it depends upon all the mods made, special parts added, applications and personal preferences.
See PBA's suggestions for the Transgo HD2 kit in post #13 in this thread:
https://ls1tech.com/forums/automatic...questions.html

I know he and other builders drill the 3rd feed hole (also called 2-3 shift hole) quite large, in the range of .100 to .125. This not only firms up the 2-3 shift as much as possible, but IMO helps overcome any small leakage in the 3/4 clutch circuit.

MUD71

iTrader: (7)

Any luck with trans I'm having same trouble? I got pinless accumulator Pistons too.

bbond105

Yes. Trans has been working flawlessly for a year now.

You may get better responds if you started your own thread. State the vehicle you have and trans type, along with any history that you feel is relevant and describe the problem as best you can. Myself or someone here will do their best to help you.

mrvedit

Please start a new thread and give us details of the symptoms of your problem. This thread is more informational and not a specific problem solver.
After you start your own thread, I will delete your post here.