3/4 clutch pack Clearance

Dynamic396 said:

Although there is quite a bit more to the 3-4 system that needs to be attended to than just the clutch itself, I have literally built thousands of 4L60E's with that 7 disc stack. It's the best setup I've found. It works and it lasts. Not so with the other "fancy" kits with their cheesy backing plates, single-sided clutch plates, or whatever their "claim to fame" happens to be...

BTW, I would box up that Transgo kit and send it back. You do not need a "shift kit" to make that transmission shift well. Plus, it will save you the hassle of broken accumulator springs and such in the future.

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hobbby3 said:

Will the 4l60e apply plate work in a 1989 700r4 or would I need to change other components? I see that it is now one piece which is where I'd have to pickup the extra clearance to make a 7 pack stack work.

https://www.gmtransmissionparts.com/3-4-clutch-apply-plate-4l60e-1993-up/

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Lucknow said:

They will normally also cause a 4L60E to bang the rev limiter on the 2-3 shift because the shift doesn't occur quick enough. 7 high energy frictions and 6 Kolene steels seems to work best. The Alto and the Z-Pak both suffer the same issues. The material is too thin and they warp.

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hobbby3 said:

Just to follow up the newer style apply plate worked just fine my 1989 700r4. Came out to .025 - .028 with a 7 friction setup but I had to use the .062 snap ring.

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Dynamic396 said:

Yeah, I'm not a giant fan of the Alto 9 disc stack, either. Sure, you get 9 frictions in there, but you have sacrificed too much thickness on both the frictions and the steels to make them much good at tolerating heat. The Alto kits measure .062" on the frictions and .060" on the steels - pretty thin... A 700R4/4L60E 3-4 clutch is kind of an anomaly of sorts. It's such a weak clutch design that convention kind of gets thrown out the window to make them last, but shift well. The thing that comes into play is not only lubrication and cooling of the plates (more clearance is better), but the quality of the 2-3 shift (less clearance is better). During the 2-3 shift, the transmission is releasing the band and engaging the 3-4 clutch simultaneously. When the valve body commands the shift, pressure is sent to the back side of the 2nd gear band servo and to the 3-4 clutch piston at the same time. The band begins to release almost instantly, so during the time between the release of the band and the engagement of the 3-4 clutch, you're, quite literally, in first gear for a fraction of a second. This is why it is so critical for the 3-4 clutch clearance to be as tight as possible, while still allowing the plates to lubricate and cool acceptably. The tighter the clearance, the less time it will take for the 3-4 piston and apply ring to travel the distance necessary to begin clamping down on the clutch plates. In either case, .107" may as well be a mile... That's WAY too much clearance. You're right in that conventional thinking provides appx. .010" per friction in the stack for good lube and cooling. But, even .090" (9 x .010") is way too much clearance. Your 2-3 shift will be a bit of a lazy, slide-shift at low throttle and, under heavy acceleration, you're likely to have some flare, especially as the plates begin to wear and the clearance increases even further. When I use a 9 disc setup (not often), I use the red frictions and kolene steels and shoot for .030-.035", and definitely no more than .040". Transgo recommends .015-.020" in their shift kit instructions, but that's for a stock 6 disc stack. You won't get away with that using 9 thin discs for very long. At the risk of giving away trade secrets, my preferred stackup, starting at the piston, goes like this: -Bonded steel piston -"7" apply ring (a "4" will work if that's all you've got, but pretty much all 4L60E's came with "7"s) -Stock return springs -Factory NEW 3-4 apply plate (OEM AC Delco only) -7 Borg Warner high energy frictions (factory 4L60E plates) -6 700R4 .076" steels (stock or kolene, your choice) -Factory NEW 3-4 clutch backing plate (OEM AC Delco only) -.093" snap ring -This stack almost always comes out between .022-.025". -On a high RPM application, I'll drill a .035" relief hole in the input drum at outer edge of the 3-4 piston bore to prevent centrifugal apply, thus dragging the plates unnecessarily. One more thing... I ALWAYS use the load release springs in the 3-4 clutch. These are important when running a tight stack because they force the apply and backing plates apart when the clutch is released, minimizing drag on the plates between them. If yours are missing, or have lost their tension, get new ones and put them in... Sorry for the novel...!

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stephx0609 said:

was this in regards to a 4l60 or 65

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