HighMileageC4

In the process of rebuiling my 96 4l60e.

I pulled the 1-2 accumulator and saw the red spring closest to the plate is broken.


I looked at my original setup and had a green outer large diameter spring and a smaller red spring that fit inside of it.

Can I keep the transgo setup with spring between piston and accumulator housing and sub my original green spring between piston and plate?

The green spring feels less stiff than the transgo spring, which I think will soften part throttle shifts, but I am not sure.

I am also switching from vette servo to sonnax billet 2nd servo so if the green spring softens the shift the new servo may compensate. Also upgrading to a wider carbon band from stock width.

Other concern is green spring is slightly tallerbthan transgo spring.

Unfortuneately I need to get this together by the end of the week., so I dont have time to order a replacement.

mrvedit

The Transgo 1-2 accumulator red spring is half-height but quite thick and stiff. I suspect your original large diameter spring would work OK, not sure how the shift feel would change. Keep in mind that you can easily change it out later - only need to drop the pan and not the valve body.

The Sonnax 2nd servo will also affect the 2-3 shift and IMHO could cause the 3/4 clutch to engage a bit more before the band is released, potentially causing a bind. Therefore, I would recommend the Sonnax servo release check valve and, as specified in the directions, drilling the 3rd apply hole to the max suggested .125 (1/8"). Lets assume the Sonnax parts are designed to work better together.
BTW - I tried the Sonnax 1-2 accumulator (from their performance pack), but found it too soft and went back to the Transgo setup.

sjsingle1

iTrader: (1)

doesnt the sonnax kit have like 4 springs in the accumulator? the stock spring setup is pretty stout IMO.......i know the trans go springs and washer would really make a difference.......not in a good way that is

mrvedit

The Sonnax Performance Pack (shift kit) has one spring under the pin-less piston and a unique pseudo-spring above it. I found it too soft and went back to the Transgo HD2 setup.
BTW - The Transgo HD2 springs do not work with a Sonnax pinless piston.

Correction - There are two springs under the pin-less piston.

PBA

When using the Sonnax 2nd apply piston with the TransGo Performance Shift kit, you can drill the 3rd feed apply hole as large as .125" - .140" and the band release hole to .104". I never use the Sonnax servo release check valve when using the TransGo Shift kits. I find that if you drill the right hole sizes in the separator plate, then it is redundant to use the Sonnax part. The Orange 2nd accumulator spring from TransGo does break occasionally. You can use a 700R4 flat wound spring in its place. The green spring you are talking about will "coil bind" if used here.

HighMileageC4

Does the sonnax 2nd apply servo make the band release faster or slower on the 2-3 shift relative to the corvette servo? Just trying to understand what the bigger 3rd gear feed does with the sonnax servo.

If I may coil bind withngreen spring, should I just go back to the stock setup with small inner and larger outer spring on one side of piston rather than the transgo style with one spring on each side of the piston?

sjsingle1

iTrader: (1)

lookin at the PDF for the sonnax instructions shows that there is a short wavy spring on top of the piston and one small OD and one large OD spring under the piston.....sorta like stock when i pulled my accumulator out.....has it changed since you had the sonnax kit?

sjsingle1

iTrader: (1)

i like how there are so many different opinions on how to build performance and improvements into our trannys......one swears by the check valve and one does not........are holes in the plate that big suitable for a DD or just for a full race tranny?

mrvedit

Sorry for my mistake, I went from memory. I got my directions and parts out and there are indeed two springs under the piston. I found it much too soft with a 3600 stall.

mrvedit

I run a .093 2nd feed hole and a .125 3rd feed hole with the servo release valve; while the shifts are quick they are quite soft under light load.

PBA: Thanks for the additional info; now I need to look up the band release hole and study the servo hydraulics again.

sjsingle1

iTrader: (1)

I think the question remains......how big does a hole have to be to be of benefit.....and when does it become to big? trial and error would be very time consuming ........

and of course is one size hole ( bigger that is ) a fit all for a DD or a strip tranny?

anybody else want to add anything?

PBA

The lower the stall, a slightly smaller the feed hole will keep the shifts a little smoother at part throttle. The way you drive, what has been done to the motor, rear end gear ratio, has a lot to do with this also. The higher the stall will allow you to use a larger feed hole since you will not feel it as much. This will allow quicker shifts at WOT. Yes, there is a balance on what hole sizes work with each other and what 2nd apply servo you are using. The Sonnax 2nd apply servo does slow down the release of the band. One thing that people need to know, is that when you install a small diameter high stall torque converter, the shifts will be "less pronounced" (less shift feel), and not "softer" as you might think. The shifts are actually quicker now due to less rotating mass. This is a good, because it is easier on the gear train. It also allows you to go larger on the feed hole sizes most of the time, which will help with clutch/band life, especially with more torque and horsepower.

mrvedit

Great explanation PBA, thank you.

HighMileageC4

Here is what I ended up doing.

I did not want to risk coil bind so I found one of my old saccumulator prings from a 700R4 from an 86 corvette (Done too long ago to remember which accumulator). It is Orange or Red, hard to tell because it was older. It was slightly taller than a large diameter 4L60E green spring, but the spring wire was thinner and looked like it had more margin to coil bind. It has a softer/looser spring rate than the $L60e green spring and the transgo spring.

Overall Full throttle shifts are very firm, firmer than before the rebuild.
Part to half throttle (which is normal due to a 3200 Stall) are firm and not too harsh. Maybe similar to how they were before the rebuild.

What I am noticing is that at very light throttle, like starting in a parking lot where you idle through 1st 2 gears, the 1-2 shift is slightly "cluncky". Not sure I like this and dont want to stress any clutch teeth or other hard parts.

Before the rebuild it had transgo spring setup, no shims in 1-2 accumulator. Piston is shortened by Probuilt. I believe .093 2nd feed. Vette Servo.

New build has same feed, the 700R4 spring replaced the broken transgo spring closest to the plate. Spring is taller but less spring rate and looser. Sonnax Servo with carbon wide 2-4 band.

I think the extra clunckiness at very light throttle is more due to the billet servo and wider band having more grab in conjunction with the transgo setup. I dont think the 700R4 spring is contributing to this, but I am not sure how the spring and offsets are working with the accumulator.

Would it be possible to improve very light throttle? I did a little searching and saw a suggestion of going back to stock dual spring setup and opening up the 2nd feed hole to .100" with a billet servo.

Can I get rid of the slight clunk and keep the firm shift at medium to WOT?

I definitely like a firmer trans, like the corvette 700R4's used to be calibrated to, maybe slightly firmer, but not the B&M chirp the tires and crash bang light throttle BS that breaks parts.

PS. My BONE STOCK 89 Vette will chirp 2nd and 3rd with the way the factory calibrated this 700R4 with stock converter stall. The 4L60e's were not calibrated this way. The Transgo shift kit on a 4L60E makes the shift similar to a Corvette 700R4, but It may be a little much with Billet Servo and Wide 2-4 Band with throttle just off idle.

mrvedit

On which side(s) of the 1-2 accumulator piston do you have springs?
I wonder if the accumulator is bottoming out to quickly; I suspect that when you open up the 2nd feed hole you also need a spring (or a stiffer spring) on top of the piston, between it and the separator plate.

The main accumulator effect is the fluid pressure, controlled by the accumulator valve, between the separator plate and the piston. The 2nd feed fluid then presses on the other side of the piston toward the separator plate. The springs only "modify" this action. (That is why the 700r4 and 4l60e have springs on opposite sides.)

Of course if you have a spring on top of the piston and it is too stiff or binds, then the piston cannot move and effectively bottoms out too soon.

I look forward to the results of your experimentation. Perhaps someone more experienced will have good advice.

HighMileageC4

Accumulator is set up per transgo hd2. A short beefy spring at bottom of accumulator housing >> piston >> 700r4 spring between piston and plate (because short red transgo spring broke).

I was in a bind since I needed my daily driver on the road and its what I had in my spare parts. As stated spring is longer, I dont think it can coil bind, and is a softer spring than the short transgo spring.

I dont think its the cause of the very light throttle clunk, but I am not sure.
Clunk is not harsh or jarring, but is noticeable and annoying. Medium and wot are very firm and agressive but not harsh and clunky. Its only clunky when sightly off idle.

HighMileageC4

Hoping one of the pros may have some advice.

carlsonauto

I would call transgo and tell them their spring broke and see if they will send you a new one. Then try putting the accumulator back to the way you had it before and see what that does. The accumulators are what directly affects your shift feel especially when driving "normal". Its pretty hard to speculate what is going on when you are using an accumulator spring combo that most likely nobody is at all familiar with. Its easy enough to play with in the car and honestly with such a unique setup Im not sure what will make it work happily everywhere..

HighMileageC4

Called Transgo and they are sending a replacement spring for the one that broke.

They told me a looser spring could cause a slide bump, where the end of the shift is harder than the beginning.

Will swap it next week.

HighMileageC4

Update.

Transgo sent the replacement and the light throttle clunk is nearly gone. It got a LOT better and goes away when fluid warms up.

It is still a little stiff when cold. Its 20 degrees here in Chicago area.

I would say this fixed because every 700r4 or 4L60e I have had is stiff when it gets this cold until it warms up.

I would say the Trango setup with a Sonnax billet servo woks well. Shifts get progressively firmer at medium and wide open throttle. Accumultor piston is modified by Dana at Probuilt to do this. No washer shims have been installed, so for future reference I would tell anyone with billet servo not to use any washers on bottom of accumulator spring closest to the accumulator housing.