AcIdBuRn02ZTS

Hey guys...

I'm setting up the direct drum in my 4l80e.... wanting to run 6 frictions...

Deleted the cushion and went with .077" steels... the gap is still too tight.

Is there any issue with running 2 .060" steels in this pack? I've heard heat could be an issue?

Its going in a 03 Tahoe on 35s... 4bta Cummins ... near 7k lbs. and will have around 550-600lb. Ft. Will also pull with it from time to time?

No racing or track use...

It was suggested that I just cut the top plate .030" instead..

I'd prefer not to do that... suggestions?

nonnieselman

iTrader: (10)

Might wanna PM this guy..
he is the transmission guru

PerformanceTrucks.net Forums - View Profile: Vince B

AcIdBuRn02ZTS

Already did... haven't heard back yet... dropped him a line on it last night.

AcIdBuRn02ZTS

I think I'm gonna go this direction unless I'm told that its not a good idea...

Currently, the forward clutch is setup without a cushion plate, 5 thick steels, 5 frictions - .050" gap

I think I'm going to set the forward clutch pack back to stock with - 1 cushion plate, 5 .077 steels, 5 frictions which also nets a gap of .050"

Then...

My direct drum is currently set too tight with no cushion, 6 .077" steels and 6 frictions...

I think set it up with no cushion, 4 .077" steels, 2 .060 steels, and 6 frictions which should get me a .060" gap

Will there be any issues with retaining the cushion plate in the forward drum? I've heard issues with harsh engagement by removing it and considering this is going in a 6k+ lb daily driver, not so sure that would be a good idea for the gear train.

I haven't heard anything negative thus far about removing the cushion from the direct drum and it seems to be common practice... if anyone knows/thinks otherwise, speak up.

Anyways... if this is a good route to take or not..... please advise

-Chris

slow67

iTrader: (2)

If you are dual feeding the directs, IMO you can't get it to shift firm enough. Even blocking the accumulator, the 2-3 isn't very harsh at all.

AcIdBuRn02ZTS

Alright... so here is what I ended up with in the direct clutch...

No cushion, 5 .077" Steels, 1 .060" Steel, 6 frictions.

Fully assembled with snap ring in place... ,measured movement at the top friction via magnetic dial indicator mounted next to the drum on my steel work bench. At the friction, I'm getting right at .060" movement which includes some movement in the top plate.

Am I good to go on this drum? From what I've been reading, .010" per friction is where I should be.

Anyways..
-Chris

smokeshow

iTrader: (16)

I'd run clearances on the tight side... You'll need to pay special attention to the valve body though. The low RPM torque of a diesel is going to stress a transmission that's meant for higher rpm load. That trans pump isn't going to be moving as much fluid behind a 4BT, especially when you can lug the thing around at 500tq+ at 1000rpms. That above all else will kill clutches.

AcIdBuRn02ZTS

Well.. I'm not too worried about the diesel aspect since the 4l80e did back many 6.5s... along with countless duramax based express vans although it was detuned for the application...

I'd say a built 4l80e will handle it just fine.

As far as clutch specs go... I've read where Jake has specified to run them at least .010" per friction in the 80e.. even looser because the 80e doesn't rely on that gap for shift timing and running them tighter just creates heat/drag which I surely don't need considering the application.

Opinions?

Vince B

iTrader: (1)

Do you have a micrometer to verify the thickness of the steels and frictions you are using? In the past I have used a TH400 waved steel as the first steel then a friction/steel/friction and so on to get six frictions in the drum when using a bonded piston. If the pack needs to be tighter I will use a direct steel to tighten things up. However it seems that you are on the opposite side of things here. The only thing I can think of is that you have direct steels and not fwd ones. If you do not use a cushion plate make sure that the first steel does not get caught in the groove in the bottom of the drum. In most cases when I build these units I will use an aluminum TH400 piston with the double apply surface. With using this piston I cut the piston to achieve the clearance I'm after. HTH and sorry for just replying now. Vince

AcIdBuRn02ZTS

I mic'd the steels as I built the pack... I've got 5 .077" and 1 .060" in it now... I'm using the bonded piston and right now have .060" total movement in the pack measured at the top friction via.dial indicator... all dry.

I'm using 6 Borg Warner high energy frictions