4T60-E harder shifting

[Mitch DOHC]

and yes i know i dont type or spell well

[wireman121]

From what I understand, the softer the spring, the harder the shift. Since when the pressure comes into the accumulator, it compresses the spring, and if the spring is softer, it will compress faster, and shift faster/harder. However, shortening the bore of the piston will also achieve the same effect, since putting washers in the bottom of the accumulator housing will tighten the spring, but cause the piston to travel less, it will work in a different way to achieve the same effect.

The opposite goes for a softer shift. If you put a harder spring in, you will get a softer shift, because it is harder to push the piston down, and takes longer, which causes a longer shift, and a softer shift. If you look at your trans book, it will explain that. Also, if you notice, the 4T60-E that came with the 4.9L motor (cadillac) had an extra spring added - which made a softer shift for those luxury car owners.

[brian89gp]

Thats backwards. The more the piston moves the longer it takes to build pressure behind the band/clutch because the more the piston moves the more fluid that is required to move it, fluid that is not going to the bands/clutches. The caddy had stiffer springd due to the engine behind it, the 4.9 is torquey enough that with soft springs it would slip a lot more then a less torquey motor.

[wireman121]

I dunno where you got your info from, but I am reading directly out of the 4T60-E transmission book from GM. it states that the softer the spring, the harder the shift...the harder the spring the softer the shift. I have also consulted my trans place about this, and they have explained it exactly the same way. If you think about it, it makes sense, and while the amount of fluid does matter, the pressure it takes to move the piston also matters....if it is easier to move, and it moves faster, then it takes less pressure...and that means more pressure will be applied elsewhere faster

[brian89gp]

First:

http://www.tobul.com/bkgd/whats.html

Second, from http://www.shoforum.com/shiftkit.htm

The kit comes with a stiffer 2nd accumulator spring and spacer.

From : http://www.alsc.aus.as/messages/1/9960.html?1057712428

One of the changes in the shift kit was the installation of a stiffer spring in the second accumulator. In the stage 2 this harder spring is replaced with a blocker rod. That is no spring at all, but a solid rod!!

from : http://www.montecarloss.com/SSThunder/drivetrain.html

The objective of most shift kits is to limit the travel of the accumulators either by stiffer springs or spacers(plus a few valvebody mods and pump operating pressures). In my personal cars, I eliminate the accumulators completely so that all the oil is directed to the clutches

from: http://www.gnttype.org/techarea/tran.../200rebld.html

Although some people like the B&M shift kit, I personally don't like using the spacers for the accumulators. I would rather use a stiffer spring, but all three work well

One last thing, if you take apart the 60e accumulator one of them has a stiffer dual spring, can't remember if it was the 1-2 or 2-3. Either way I had a spare accumulator around so I took the dual spring out of it and put it where the single spring went AND DID NOT SHIM IT. Funny how those shifts got firmer with a stiffer spring....


An accumulator will absorb the initial shock of the fluid passage building pressure, the very shock that will engage the clutches faster. Limiting the amount of shock the accumulator absorbs will determine how snappy the shifts are, you can do this by either increasing the spring rate so its harder to press the piston, or by limiting the pistons travel with a spacer.

[4spdz34]

brian u say not to put the washer under the piston, betwwen the spring and the piston? my piston is a cup and the spring goes into that cup, when i did it i put the washers in the cup of the piston. if u put it on the other side of the spring its only going to limit the ammount of fluid that is allowed to move out of the accumulator housing. and mitch DOHC i find it hard to belive that your trans barks the tires into 3rd. did u mess around with the accumulator for that shift? cause even if there was a rod in there it could'nt bark the tires. and 500 for that converter, u got ass raped. all the hardened sprag is is a updated gm part, its not hi-performance or anything

[brian89gp]

http://www.brian89gp.com/misc/accum.JPG

Black is the accumulator body, green the springs, and red the washers. The idea is to pre-compress the spring some thus raising the spring rate. It will also cause the piston to have less travel cause the spring will bind sooner.

Putting the washer between the piston and spring will do the same thing, except the since it will move up and down in the bore the steel washer will eat the hell out of the accumulator housing.

[4spdz34]

ok brian i understand what u are trying to say. either we have different accumulator pistons or u don't know what i'm saying. from your site hope u don't mind but i don't have pics.

http://www.brian89gp.com/images/turbo/accumulator/DSCF0066.JPG

ok notice how the pistons are about 3/4 of inch deep, well in the middle of the piston there is the center that the accumulator piston rod rides on, its just as deep as the piston. well you put the washer inside of the piston cup and around that material in the center a 2in od washer fits perfectly around the center. and because of where it is it will never touch the rod or the walls.

[brian89gp]

I don't see why that way wouldn't work either, as long as its impossible for the washer to contact any moving part.

[wireman121]

brian89gp, ok guess I'm wrong then, i respect that you know much more than I ever will, so I was wrong :-) However, looking at the pictures..

http://www.brian89gp.com/misc/accum.JPG

http://www.brian89gp.com/images/turbo/accumulator/DSCF0066.JPG

DSCF0066.jpg is exactly what I have, and from the accum.jpg, that is exactly what I did. However, I am going to assume that by removing 2 washers from my 1/2" stack, it drastically changed the shift, and if I add the 2 back in, it will shift much harder than it is right now?

[brian89gp]

The first washer makes the most difference because it sits on that shelf (http://www.brian89gp.com/misc/turbop...2/DSCF0067.JPG). Adding individual washers should make some difference but no where as noticable as the first one. And yea, thats the gist of it.

And if you can prove me wrong with the stiffer/softer spring issue, please do; I'd hate to be giving bad advice :P I'm pretty thick headed but don't let that bother you. hehe.

[wireman121]

ok so tomorrow i am adding the extra washers that i left out last time i did this. Should I just add the 2 to each accumulator to make up the 1/2" or should I add 3 more to each, to make it a little more than 1/2"? i barely got a response from the current amount of washers, and id prefer to get it right this time instead of trying 3 more times

[Mitch DOHC]

Quote:

The objective of most shift kits is to limit the travel of the accumulators either by stiffer springs or spacers(plus a few valvebody mods and pump operating pressures). In my personal cars, I eliminate the accumulators completely so that all the oil is directed to the clutches



ok how do u bypass the acumilators and why would u want to do that

[jweir22]

Washers

Would it be better if i made one big 1/2 inch washer inside of 6 or 8 small ones.Just wondering.

[grandprix34]

don't know about the harder shifting but there is a discussion over at w-body.com about wiring the 2nd gear start switch w/performance shift points. I am going to be the guniea pig, so as of now I am starting the "help repair my tranny" fund so paypal me whatever donation you wish! lol

its on page 6, (on page 5 i have a 0 - 100mph run on my auto DOHC).

here's the link:

http://w-body.com/forum/viewtopic.php?t=17672&postdays=0&postorder=asc&start=75&sid=4228b013dc44a4326a49b9dcbb9d40db