Diog

Hey Guys!! It's been a LONG Time since posting here on LS1Tech.
This is about the 1-2 Accumulator Spring(s). Here it goes ....

I'm replacing my 1-2 Accumulator in my 4L60e. My Car is a 2000 Z28, Bone Stock.
(No Shift-Kit or anything creating excess Power passed the Stock Setup) All OEM Parts in the 4L60e.
I have just purchased the Sonnax Pinless 1-2 Accumulator, PN#77998-03K. I have read the Instructions, and Understand how to Install it. But I need to know what Spring(s) are supposed to be used with it, if they need changed.
I did read somewhere that a few people Installed the Sonnax 77990-03K in their STOCK 4L60e, and Complained about a ridiculously Hard Shift. It may have been an SUV or Silverado Truck, Idk. But Definitely Stock 4L60e's.

I am changing my ATF to Synthetic Valvoline Dexron VI, exchanging it with the Trans Pan off and installing a New WIX Filter when done. I am Exchanging ALL the Fluid out, and have 1qt of ATF Conditioner to add when done. I have (2) 4-qt Jugs & (4) 1-qt Bottles of ATF.
(Just FYI)

While the 4L60e is open, I am replacing the 1-2 Accumulator to the Sonnax Pinless just to make sure I don't have issues with my car down the road. The 4L60e has no problems. The car has 80k miles, and was noticeably slow to accelerate last winter below 20 Degrees F. So I know the Fluid needs changed. I isn't burnt, and is a darkish-red. Mostly Highway miles I drive.
I have had the car since 2004 when it had 18k miles on it. Ever since I've owned the car, the 1st to 2nd Gear was always Stiff compared to the other gear-shifts. I've been told by many who have the 4L60e, that the 1st to 2nd Ratio is higher than the other gears, and creates this 'Crisper Shift'. A lot of people with LS-Cars tell me this is how it is supposed to be, and many like it even Stiffer. But 1st to 2nd is 'Crisp' enough to loose traction in cold wet weather. In fact, even accelerating super slow at just 1,000 RPM, I can loose traction with 2 inches of Snow on the ground. [LoL] I always hate that.

Over 10 years ago at 25k miles, I poured Half a quart of Lucas Transmission Fix in to see what it would do, and it did help. But only to some degree. I'm sure most people think my Standards for how an Automatic should shift in an LS-Car are lame. But I do like a Smooth Shift as opposed to a hard shift. (At least with normal driving around town)
I used to have a 1994 Z28 with the same Transmission, and it was Smoother.
(Maybe Less Power = Smoother Shifting?!?)

I read on many forums that the Accumulators in the 4L60e actually determine how the Shifts Feel. I've had my Z28 for over 13 years, and just learning this stuff.
I Figured since I am doing an ATF Change, I may as well install a Pinless 1-2 Accumulator while I'm at it.
I've read that the OEM Accumulators are Plastic, and even replacing with an Aluminium part leaves for possible issues for wear of the Pins which can allow ATF to leak through and cause issues. And the 1-2 is the one that Wears the most, since it shifts almost every time we push on the gas.
If I'm replacing the 1-2 Accumulator, I may as well install the Pinless Sonnax.

Now, I'm reading many forums about how Installing the Pinless Sonnax Accumulator can create Stiffer Shifts??
But it is the Spring that actually Determines how hard or soft/Crisp or Smooth the gear changes are. And at least for our 4L60e's, the Stiffer the Spring, the Stiffer the Shift.
Which obviously means the Softer the spring, the Softer and Smoother the Shift.
I'm not trying to jello my shift, just get it to 'Glide' a little smoother.
And I DO know that a hard-shift is harder on the actual Gears.

*So my Real Question is: Does using the Stock Spring with the Sonnax Pinless Accumulator create a Stiffer Shift than with the OEM Accumulator?!? And if so, what is the Appropriate Spring that is just a Step Softer than the OEM one??
**Links to Additional Info and Springs are Appreciated**

sjsingle1

iTrader: (1)

having used the pinless pistons in several of my trannys I can say I dont think it adds to a harsher shift quality.....the benefit of the pinless design is it avoids the problems of the stock design...plastic pistons cracking and aluminum pistons wearing out the bore where it rides the pin leading to loss of sealing

I use the pinless pistons as they are a part of the sonnax sift kit HP-4L60E-01 which includes their springs in the 1-2 location

I believe you can use the stock springs in the accumulator with the piston....but I am not the expert and I am sure someone with more experience may correct this opinion

I have always felt the 1 -2 shift as being very firm....I read in some post that the best fix is to tune the shift pressure lower to soften it....as soon as I get my HP tuners I will be trying that first thing

ok forum experts.....chime in

Diog

So what spring are you using with your Sonnex Pinless Accumulators?!?

clinebarger

A Sonnax pinless accumulator piston will make the 1-2 shift Firmer as it has limited travel compared to a stock piston.

You need to drop the 1-2 accumulator housing & check for a broken spring & see what piston "style" you have so you can order parts. Or maybe order a loaded accumulator housing from a Vendor (If that's offered?)

Plastic pistons breaking is not that common, Broken springs is way more common!

A loose 2/4 band will also contribute to a harsh 1-2 shift.

sjsingle1

iTrader: (1)

I am using the springs that came in the sonnax shift kit

Diog

Dang. So if everything inside the 1-2 Accumulator is in good shape, what Spring would be right for the Sonnax Piston, if I want the softest Possible 1-2 Shift using this Pinless Piston??

Diog

*If I wanted to increase the Travel of the Sonnax Pinless Piston, would shaving the 4 Feet down help to keep the shifts OEM??

Diog

SJ - How does the HP-4L60E-01 Kit change the shifts at low speed and low acceleration?!?
Or does the kit only change the shift-feel at higher RPMs??

mOtOrHeAd MiKe

iTrader: (8)

I hope these help a little:
https://ls1tech.com/forums/automatic...ce-needed.html
https://ls1tech.com/forums/conversio...l#post19502993
https://ls1tech.com/forums/conversio...l#post19502994

IMO, installing the Sonnax 4L60E Performance Pack is well worth the added effort.

clinebarger

There really isn't a spring combination that will work with the Sonnax piston & give a softer 1-2, The "best" spring combination is the original springs or the springs in the Sonnax shift kit.

That will help, Probably still harder than a stock piston & spring combination!

The 1-2 will be firmer at all throttle angles than stock! Especially if you follow the printed instructions.....It's a performance product, It will accomplish the opposite of what your after!

If you just want to mess with the 1-2 Accumulator housing......Use these parts.
Piston Pin, GM# 8684426
Piston "kit" GM# 24214343 Comes with the 3-4 piston also but cheap enough, The 1-2 piston is plastic.....So what!
Outer Spring, GM# 24209794
Inner Spring, GM# 8685656
These parts will restore your accumulator housing to like new condition given the housing (bore) itself is OK.
**Using Trans Go SK 4L60E (Orange Box) spring set-up WILL calm the 1-2 compared to the stock springs, However I personally have seen these spring break WAY to often to recommend them, If/When one breaks.....Back to square one!**

If you INSIST on using a Sonnax pinless piston......
Outer Spring, GM# 24209794
Inner Spring, GM# 8685656
Trans Go separator Plate# 46-PLT-96
Sonnax Servo Apply Pin# 77787-02K
Servo Cover O-ring.
Separator plate gaskets.
Drill the Trans Go Plate like so.....
2nd Feed .070"-.073"
3rd Feed .101"
4th feed .101"
Reset the 2/4 band clearance with the Sonnax apply pin to .040"


If you want to use Sonnax HP-4L60E-01.....
-DO NOT install the Accumulator Valve Spring Spacer!!
-Purchase a Trans Go separator Plate# 46-PLT-96, DO NOT drill out the second feed hole! You can follow the rest of the recommended hole sizes.
-Purchase a Sonnax Servo Apply Pin# 77787-02K, Set band clearance to .040"
-I would suggest using a "B" code accumulator Bushing & Valve out of a 700R4, I don't think anyone reproduces this part....A used one should be easy enough to find at a local trans shop.....Make sure it comes with the End Plug along with the Valve & Bushing!!
-See if the shop has a spare Trans Go SK 4L60E accumulator bushing pin & 5/32" drill bit.....This will allow Accumulator Bushing & Spring changes without dropping the valve body.

Diog

**UPDATE** !!

Ok, so I've removed the Accumulator, and taken it apart.
Everything is in Really Good Shape inside. Here are some things I've Noticed:

- Before taking it apart, the Piston is On-Top of the Spring. [Original / OEM]
- The Accumulator Housing inside is setup so the Inner Spring is Recessed. Which is why before I took it apart, there was something 'rattling' inside. None of the springs are broken, and all parts appear in Excellent Shape.
And.... (Drumroll.....)
- The 1-2 Accumulator Piston is CERAMIC Not Plastic!!
It LOOKS like it's plastic. It's Tanish-Grey in Color. But if you tap it against the housing, it makes a 'Ring/Ding' sound like a dinner plate. It also has some weight to it, and Feels very smooth and rigid. NOT Metal OR Plastic!!
This would explain why the Accumulator Piston can crack: It's very Rigid, and probably would not hold up to Excessive Temps. But under proper conditions/low miles [I have 80k], it appears to be almost like New.

When I first pressed-down on the Piston after removing the Accumulator, it shot-out ATF like a Water Gun. [LoL!] I wasn't ready for that.
It Did feel reasonable smooth, once you put some Might into it.
As I've stated above, there was something rattling inside. At that point, I was thinking a spring was broken. But it was just the Inner Spring loose due to the Recessed 'Dome' at the Bottom of the Accumulator around where the 'Pin' (It's a Shaft) is held in place.
This means, that the Larger/Outer Spring is held Tight against the Piston, and the Inner Spring is loose until the Piston travels down enough, increasing Tension once the Piston travels further into the Accumulator. (When there is Higher Pressure/Heavier Acceleration)
Basically the Larger Spring is for Normal Operation, and the Inner Spring just keeps the Piston from Bottoming-Out under High-Load at heavier acceleration.

I did inspect all of the parts. Everything is in Good/Excellent Shape. The Pin looks very good, as well as the Piston. Though when I started spinning the Springs around inside the Accumulator, I found that the Inner Spring seems to be slightly cockeyed/off-center. After checking the Inner Spring, I think it's actually a flaw inside the Housing itself, where the Inner Spring sits.
[The 'Dome' around where the Pin is held in place]

I reassembled the Accumulator with the OEM parts and left some ATF inside of the cylinder-walls. I pressed on it, and it felt pretty good. It had just a slight binding, which could just be the Springs rubbing against the inside of the Piston or something.
It felt reasonably Smooth, but not like a shock absorber. It did feel like the Springs were scratching either the Piston or each other as I pressed down on the Piston.

I put together the Sonnax Piston, installing the D-Ring (Rubber O-Ring) and the 'Seal' (Which is PTFE NOT Rubber). I removed the Pin (It's a Shaft), put some ATF on the sides of the Piston, and installed the Springs. I installed the Piston in place on top the Springs, like the OEM Setup.

At first, the lower Seal (PTFE) was rigid but went into place no problem. But getting the Top Half of the Piston, which is the Upper Seal [Rubber D-Ring] down into the Accumulator was pretty hard. I did get it into place just to get a good feel in Comparison to the OEM Piston.

It was Binding. I could tell it was the Seals catching on the Cylinder-Walls. Even though I put a decent amount of ATF on the Seals (D-Ring & PTFE Seal), it just felt like ****.
I know this is a NEW Piston with Fresh Seals & D-Ring, and they might just need a little breaking-in. But in Comparison, the OEM Piston felt WAY Better, a Night & Day Comparison!!

I called up Sonnax. The guy said it just needs to be Installed, and get ATF Circulated around it to properly work. He Also said it should shift very much like it originally did, unless there was something wrong before hand. He said it should feel like the OEM did when it was New.

So, here I am. ATF everywhere, and I'm not sure I should even Install the Sonnax Piston.
To be Clear, I have NOT Installed the Ball in place of the Pin (Shaft). I just wanted to see how the Sonnax Pinless Piston moves compared to the OEM Piston.

Naturally, I would Finish-Up Installing the Sonnax Ball into the hole for the Pin, and Install everything as Originally Planned. Just to see how it Drives, hoping the guy at Sonnax is Right about having a 'Factory-Feel with Improved/Restored Operation'.

I Figured I should get your Thoughts on this before I do.

Diog

I think the Reason that this Sonnax Piston feels tough to move inside the Accumulator is due to the overly TIGHT Rubber D-Ring/O-Ring.
The PTFE 'Seal' is about right, reminds me of Engine Piston Rings.
Yet I think it's also possible that the Piston itself is actually binding abit inside the Accumulator-Bore.
This is really frustrating!!

You would think they would know what Exact Size the 4L60e Accumulator is.
I don't have the tools to make this a perfect-fit. It could be the D-Ring/O-Ring is just Way too Tight. It is New afterall.

But then, how does a New Stock Piston & O-Ring feel when Installed??
Are they really Stiff inside the Accumulator Bore?

As I've said in the post above, Sonnax told me that it will feel Stiff inside the bore until I Install it, and get the ATF Circulated inside the Transmission when Driving/Idling. Makes some sense, but then if the Piston I Removed was much smoother to move inside the Accumulator, then shouldn't this one feel Similar?? Or does it need some Break-In Time?!?

Given this is my Last Chance before the nasty weather kicks-in, I need to make a decision on which to Install: The Stock Piston & Pin, or the new Sonnax Pinless Piston?? One will Work as I know it has, and the New one might not be right.

clinebarger

The Sonnax pistons can be pretty stiff in the bore, It will loosen up with some cycles.