StolenFox

My rebuild kit comes with a lot of options so I am hoping some of you experts can chime in and give me some direction on the following:


3/8" cup plug for dual feed: Install in the case hole just to the right of the center support bolt hole (ATSG #43 labeled "reverse")?

3-4 Accumulator Delete: Should I delete the accumulators with a block off plate for a 450hp LS in a 3900lb BMW daily driver using a higher stall OEM converter using stand-alone electronics and "tap-shift" frequently? Any recommendations regarding hole sizes to be enlarged in separator plate?

Check ball locations: Do I use them all? I would assume if I delete the 3-4 accumulators then those checkballs are unnecessary.

Tapered metal and rubber/plastic bushing: Came with the block off plate, have no idea what it's for...

1-2 accumulator piston: Do I omit the sealing rings from the piston?

Additional Friction for the Direct Clutch: How do you add the extra friction that was included in the kit without increasing the overall stack height of the clutch pack and reduce the clearance? Do you have to omit the wave plate or use thinner steels (.77) out of the forward to maintain stack height?

Thanks in advance for anyone who can help answer these!

S.F.

clinebarger

Yes, Block the Reverse passage that leads too the Center Support, Omit the Lip Seal in the Direct Drum, Omit the Second Sealing Ring on the Center Support, Omit the Reverse Checkball in the Case....(For faster Reverse Apply that got slowed down by blocking the Reverse Direct Clutch Feed.)

I generally drive a Checkball into the Reverse Feed hole in the Center Support & Block the Case Feed Hole with a Cup Plug, But the Center Support hole is an odd size, A 700R4 TV Exhaust Checkball is the perfect size, Not a big deal though, It just seals up what little 3rd gear oil that will leak between the Support & Case.

I personally would not block the 3rd & 4th Accumulators on a mild street car with a restalled factory 310mm Converter, You can't get much stall out of stock converters.

Run 7 Case Checkballs, Omit the Reverse Checkball.

"Tapered metal and rubber/plastic bushing", Sounds like a Drive in Seal for the Direct Feed Hole in the Case (Left of the Center Support Bolt), You got a picture of it....Because i'm guessing.

"1-2 accumulator piston: Do I omit the sealing rings from the piston" No, Sounds like some Trans Brake instructions, Besides you want an active 2nd Accumulator (In my opinion)

You don't need 6 Direct Frictions, Using .077" steels doesn't always work out Clearance wise. I machine Aluminum TH400 Pistons to fit full thickness Steels when running 6 Frictions, I feel it is the correct way!
But, You are in no danger of 5 High Energy Frictions burning down at 450 HP Assuming good Line Pressure/Pressure Rise.

StolenFox

Thanks for your reply! The company I bought the rebuild kit from got back to me and answered my questions. Some of them were my mistake for reading the wrong set of instructions... I am on the fence about what to do with the 3-4 accumulators. I understand why many people (my supplier, whom I trust and respect is included) recommend blocking them and that the side affect is a harsher garage shift. I want to build in the extra capacity into the transmission from the get go in case I decide to turbocharge it but I don't want it to be a kick in the head or chirping the tires when I put it in gear... I really wish I could ride in a car with each setup and see how aggressive they are. This is my first rebuild and I, A = don't want to screw it up and B = want to get a calibration that matches the car. I guess worst case, if it were too harsh for my liking I could always drop the pan and put the accumulator assembly and check ***** back in.

bbond105

If you plan on using a 3000 or higher stall converter, the converter will soften the gear engagement.

clinebarger

^^I agree, Depends on the stall. What is the rated stall of the converter your going to run? You mentioned a stock re-stalled converter, I would be surprised if you get more than 2500 out of a 310mm.

If you end up with a sub 3200 stall, Keep the 3rd Accumulator active, You can block the 4th Accumulator by removing the Piston Guide Pin & tapping the feed hole with a 5/16" tap, & block the hole with a 5/16" set screw, Reassemble with the guide pin, Piston & Spring.

This is your daily driver, Slam/Bang shifts will get old real fast, You have to keep in mind that you dual feed the directs, That adds a ton of capacity to the 3rd clutch.

I'm not disagreeing with anyone, Just stating my opinions, There are MANY factors to Shift Feel, ....Their are even more opinions on how a shift should feel, And it differs with Stall, Weight, Gear Ratio, RPM, Horsepower, Torque, Intended usage & personal preference.

jakeshoe

iTrader: (14)

A little insight that relates to most transmissions but the 4L80E specifically.

As stated the converter stall speed greatly affects shift feel. A higher stall speed will make the shifts softer all around usually, especially when under the rated stall speed and from idle.

Accumulators...
A very necessary part of the hydraulic design for an OEM transmission. They help achieve shifts that are acceptable to the average consumer that wants smooth shifts with no feel.
I also feel that in certain cases they should be retained even in performance combos.
It's hard to design a circuit that upshifts and downshifts well. Accumulators can help with this.
That said, they aren't always necessary.

Shift feel is affected by line pressure, clutch pack design and capacity, orifice sizing, accumulator design, converter stall, rear ratio (more than many realize and not necessarily how you would expect), tires, vehicle weight, etc.

In the case of a 4L80E, dual feeding the direct clutch doesn't make it shift harder. It would actually soften the shift with no other mods.
You can control the shift feel working with or without accumulators using the orificing in the plate and checkball locations.
The plate orifice sizes would be different with accumulators than without.
In the case of the 3rd and 4th accumulator on a 4L80E, we kill them on most of our builds. We control shifts via orifice sizes.
This reduces the chance of crossleaks or pressure leaks and we've had good results and feedback doing so.
My experience is also that accumulators for higher gears aren't as necessary because the road speed is high enough that you don't feel the shift as much.

LSswap

Jake. Assuming dual feed, 3000 converter, no 3 or 4 accumulator, what size feed orifices are using?

Helomedic1171

I found this thread while searching for info about dual feeding the direct clutch. Jake, you mentioned that dual feeding will soften shifts assuming no other mods. during a stock rebuild, is this something that should be done? does it enhance durability?