Drj8787

When I tore down my trans and VB there wasn't a spring under the plate with the 3/4 accumulator. What is the purpose of this? It has the alum 3/4 and plastic 1/2 .
And no I didn't mis place it lol

mrvedit

The primary "ingredient" of the 1-2 and 3-4 accumulators is pressurized fluid between the separator plate and the piston. Similar to a shock absorber. The pressure of the accumulator fluid is set by the Accumulator Bushing/Valve spring in the valve body. (This is the spring in Step 4, Page 2 of the Transgo HD2 kit).

The accumulator springs "modify" the action of the accumulators. Putting spring(s) on the side of the piston away from the separator plate causes faster/firmer shifts.

For the 3-4 accumulator some 700R4 and early 4L60E models had the spring on the separator plate side of the piston; I think this would soften the shift. Later models and shift kits, e.g. the HD2, put the spring on the piston side away from the separator plate.
So, a missing spring would give you a relatively soft 3->4 shift. For a firmer shift assemble it by inserting the spring into the case, then the piston, then the separator plate, exactly as in the HD2 instructions.

ferrellrooster

This is exactly correct. The only reason I'm even chiming in is because I lost 2nd. It just tacked out. I have a strong first, no slippage, then shifted to second and just tach'ed out, wasnt catching at all to even slip, let off and shifted to 3rd. whined that out with no problems but feather it so it will not downshift to passing gear aka 2nd. But would not shift to 4th. Like no shift to 4th what so ever. So i read as much as I could and found that this plastic accumulator piston is the main culprit. I also read but have not verified that you can not program the shift points with the pin less piston. So I bought the billet one with the pin and springs. Double seals on the piston and the extra length keeps it from cocking and hanging up and yes this was the problem in my 4L70E behind a 6.0. Thanks for the info on here. A lot of the stuff you listed is hard to find especially as specific as you posted.

Drj8787

When I bought the car 5 yrs ago the guy I bought it from said "I went threw a couple 4l60e's in a short period of time once and my trans builder told me that hard wot shifts into 4th is y I keep braking them and said that I need to stop letting it shift into 4th so hard"

Is there any truth to this? Could this be why there is no spring for happy medium between spring on case side vs plate side?
Thanks

bbond105

What part in the trans keeps braking?

Drj8787

Nothing since I've owned it, I was quoting the guy I bought it from 5 yrs ago I don't remember what he said he kept braking but I want to say it was a snap ring for some reason .

But recently the torque converter came apart, while I was tearing down the trans to check things out for damage and debris I noticed that there was no spring with the accumulator under the plate.

So I was wondering y someone would leave it out?

mrvedit

Accumulator springs do occasionally break; not uncommon in the 1-2 accumulator as there will be many WOT shifts and WOT maxes out line pressure which causes faster shifts.
WOT 3->4 shifts are uncommon as, depending upon rear ratio, it would be between 120 and 150mph.
However, some "hack" mechanics significantly increase line pressure at all times by excessively adjusting the set-screw on the Pressure Control Solenoid (PCS). While some people might like the resulting extra-firm shifts, it is very hard on the trans, u-joints and rest of the drivetrain.

The next time the valve body is off, I would put the 3-4 accumulator spring back in, but I wouldn't remove the valve body just to do that.

Drj8787

Ya it's off right now whole trans is tore down gonna call Dana today about rebuild kits, the converter was still under warranty so it's been sent off should have it back fri or mon I think

Drj8787

Order a kit from probuilt last nite, it aways nice to have guys like Dana (PBA) around for incite and just good ol' conversation. He's forgoten more about this stuff than most of us will ever know about it.

Thanks Dana, great talking to you

Asyoung96

How do you pull out the 3-4 piston? Does it just come out or do I need to do something special to get it out?

bbond105

Pull the pin out, then sick something in the piston hole and pull it out.

Drj8787

For the case side blow a little air where the check ball was with your hand over the accumulator. Some thing with the housing side blow a little air in it they pop right out like this

Asyoung96

Thanks guys. Just finished putting the shift kit in and my camaro shifts perfectly.