4l80e bonded pistons
Thread Starter
Joined: Sep 2007
Posts: 4,188
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From: woodbine, md
4l80e bonded pistons still working on this 4l80e, kind of rebuilding the parts as i put them in the trans-the direct clutches and forward have the bonded pistons-no problem on the direct, got the piston, and just replaced the inner lip seal
the forward drum has the same deal, but the inner seal is not like the direct, it looks more like the inner seal is bonded to the drum, although it has a stamped look like the piston-transtar only shows the piston, and a lip seal for the drum?
i hope you dont have to replace the whole drum just to get the seal-wish they would of left the pistons like the older ones, lol
the forward drum has the same deal, but the inner seal is not like the direct, it looks more like the inner seal is bonded to the drum, although it has a stamped look like the piston-transtar only shows the piston, and a lip seal for the drum?
i hope you dont have to replace the whole drum just to get the seal-wish they would of left the pistons like the older ones, lol
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Joined: Dec 2008
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From: Az
still working on this 4l80e, kind of rebuilding the parts as i put them in the trans-the direct clutches and forward have the bonded pistons-no problem on the direct, got the piston, and just replaced the inner lip seal
the forward drum has the same deal, but the inner seal is not like the direct, it looks more like the inner seal is bonded to the drum, although it has a stamped look like the piston-transtar only shows the piston, and a lip seal for the drum?
i hope you dont have to replace the whole drum just to get the seal-wish they would of left the pistons like the older ones, lol
the forward drum has the same deal, but the inner seal is not like the direct, it looks more like the inner seal is bonded to the drum, although it has a stamped look like the piston-transtar only shows the piston, and a lip seal for the drum?
i hope you dont have to replace the whole drum just to get the seal-wish they would of left the pistons like the older ones, lol
As TP said the molded seal pressed in the center of the drum can be omitted in the forward clutch the only affect may be a more aggressive apply into gear when moving from neutral to drive
__________________
You can leave the center seal out of the direct too 
On the TransGo -3 kit, it is dual feed anyway so it's redundant, but the TransGo kit would be way less complex if they weren't saddled with the requirement that it can be installed without trans disassembly.
Drill a bleed hole in the direct drum about .050" and leave the center seal out. It will save you some trouble later on....
On the TransGo -3 kit, it is dual feed anyway so it's redundant, but the TransGo kit would be way less complex if they weren't saddled with the requirement that it can be installed without trans disassembly.
Drill a bleed hole in the direct drum about .050" and leave the center seal out. It will save you some trouble later on....
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Basically, the seal removal creates a firmer apply as it is an accumulator and the .050" hole compensates the firmness by releasing fluid at lower pressures, such as cruising. At full throttle this will not be noticed, it will be firm. Hey Jim, if you don't like a firm engagement into gear, leave the seal in the forward drum, especially if your not using a wave steel in the forward drum. Brian.
I personally do not think that the firmer apply going into forward on a 4l80e is worth the added holding power for the forward clutch. My thoughts here concern the OD roller. This is a weak point in this unit to begin with and it slamming into gear can not be good for this component. Besides the forward clutch usually only fails when it is run low on oil or when the ring surface in the forward drum is damaged because of worn bushings. Just a thought. Vince
Basically, the seal removal creates a firmer apply as it is an accumulator and the .050" hole compensates the firmness by releasing fluid at lower pressures, such as cruising. At full throttle this will not be noticed, it will be firm. Hey Jim, if you don't like a firm engagement into gear, leave the seal in the forward drum, especially if your not using a wave steel in the forward drum. Brian.
I don't recommend drilling a bleed in the forward drum. I am speaking of the direct drum, there are several reasons for a bleed on this drum.
You won't gain firmer shifts by leaving the center seal out of the forward drum except on initial forward clutch apply when you shift from park, reverse, or neutral to any forward gear and drive oil goes to the forward clutches. The fwds are not a shifting clutch pack.
If you have reasonable line pressure at idle, stock levels are fine here, then the seal isn't mandatory in the center of the fwd drum.
You can go either way on this.
I agree. I was refering to the direct drum. The forward clutch is the holding clutch and does't require a firm engagement, for clarity. All the harsh engagement will do is brinell parts.
Teching In
Joined: Jul 2013
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Ok I'm new to this site, I hate to bring back a dead thread but, I have an 02 4l80e that fried the forward clutch, just was wondering if its ok to leave out that center seal using the molded piston. The seal was pressed or appeared to be, I had a doubly hard time removing it because when the clutches burned up it really fried that rubber. I'm not using any shift kits or anything else I'm just going for a stock rebuild. Any help would be greatly appreciated.
