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I'm building a specification sheet for a 700R4 rebuild.
I've got the usual list of upgrades on the list.
But after talking to my (potential) builder, when asked about the 3-4 clutch pack, he said he likes the Raybestos Z pack. While I'm familiar with the name, I had no idea that they were one-sided clutches and work without any steels.
Pro-Built Automatics (Hey Dana. Are you listening?) has them listed in the 700R4 section. No horsepower or torque rating though.
I just forwarded your post to my buddy/trans builder. I'll post back when I hear from him. I know he used the Z-pack at one time, but I thought they became unavailable, maybe just temporarily?
His 4L60E builds last for several seasons behind his and my 600+ hp motors.
Thanks for that 86. Yeah, I had read that the z pack disappeared for a while. I think maybe 5 or 6 years ago. It seems they're back. Of course the internet is full of good and bad things to say about them. By builder mentioned them in our pre-build conversation and it peaked my interest.
Let me know what you hear.
Here's what my guy says: "I have used them all and prefer 10 to 1 the Z Pak. I set them up at .010 to .015 (dry measurement) and then soak em before install. Under severe shifts, they last and last and shift and shift."
Well, that's encouraging news. Seems like my guy and yours are on the same page.
I'm going to have it built this way rather than buy one complete because I think there's some value added. From what I've worked out in terms of parts, I can get an equivalent transmission built to my specs for about half of the cost. Keep in mind that I take it home in an untested condition and there's no warranty (per se) but I'm willing to take that "risk".
Thanks for that. Much appreciated.
My thinking too. Plus, local means that I don't have to deal with a 30% premium on the U.S. dollar. That's a big hit when you get into the thousands of dollars. I also get about 45% off at the GM parts counter so that's a real bonus. A lot of the upgraded components are ACDelco.
With the parts list I've put together, about the only thing left out of the ultimate build are the various shafts that could be hardened or cyroed. There's a limit though.
The Z-Pak "as is" does not work well in performance applications with more than 475HP - 500HP from what I have heard from other builders and what I have seen on these. I add an additional two clutches and this helps a lot, in terms of longevity. Quality is not consistent with Raybestos as with the Borg Warner clutch material. I prefer Borg Warner Hi-Energy clutch material in the 3-4 clutch setup. I use 8 or 9 clutches here depending on horsepower and application. In a 700R4 using my modified TransGo Shift kits I setup the 3-4 clutch clearance at .035" - .055". In a 4L60E using my modified TransGo Shift kits I setup the 3-4 clutch clearance at .020" - .035". The 4L60E uses a shorter apply ring #7 than the 700R4 does, #4 apply ring and requires different clutch clearance depending on which apply ring is being used.
Last edited by Pro Built Automatics; Nov 26, 2016 at 06:00 AM.
The Z-Pak "as is" does not work well in performance applications with more than 475HP - 500HP from what I have heard from other builders and what I have seen on these. I add an additional two clutches and this helps a lot, in terms of longevity. Quality is not consistent with Raybestos as with the Borg Warner clutch material. I prefer Borg Warner Hi-Energy clutch material in the 3-4 clutch setup. I use 8 or 9 clutches here depending on horsepower and application. In a 700R4 using my modified TransGo Shift kits I setup the 3-4 clutch clearance at .035" - .055". In a 4L60E using my modified TransGo Shift kits I setup the 3-4 clutch clearance at .020" - .035". The 4L60E uses a shorter apply ring #7 than the 700R4 does, #4 apply ring and requires different clutch clearance depending on which apply ring is being used.
Thanks for that Dana.
At about 450 hp/ 450 tq, I suppose that puts me on the edge of what the Z-Pak will handle. My builder mentions that he likes to use them and I had heard conflicting stories. Seeing as he is the builder, I can't challenge his selection too vigorously. I haven't discussed with him how he sets the other clutch packs. I suppose I shall find out.
Last edited by skinny z; Nov 26, 2016 at 11:42 AM.
