Completed my first transmission rebuild.

[pwtr02ss]

I've heard a lot of conflicting stories in regards to the Z-Pak. Some like it and some did not. like you I decided to go with the 6 high energy frictions. A website called "RigidAxle" sell rebuild kits and for their 4l60e kits they switched from the Zpak to Alto red eagle frictions stating that they had better customer luck with those.

Zpak works great in applications that are not heavy or doing towing. I have a zpak in my Camaro. It's great for that. The issue with them is you lose material thickness to gain the extra stacks. That doesn't do well when you combine heat. The steels warp much quicker. Warped steels equals uneven clamping area.

During my research in the past, I've yet to hear much good about alto (3/4 pack) frictions. I say that but I've never used them. @Just Fishing mentioned that he had good luck so that's one person that I know of personally. I do always buy the red stuff band and I think it may be made by alto. I just thought if that as I was typing. So maybe they aren't as bad I had read, lol. I prefer borg frictions. Side by side with Raybestos, the Borgs held fluid better. My own testing btw

 

[chevrol8t]

Zpak works great in applications that are not heavy or doing towing. I have a zpak in my Camaro. It's great for that. The issue with them is you lose material thickness to gain the extra stacks. That doesn't do well when you combine heat. The steels warp much quicker. Warped steels equals uneven clamping area.

During my research in the past, I've yet to hear much good about alto (3/4 pack) frictions. I say that but I've never used them. @Just Fishing mentioned that he had good luck so that's one person that I know of personally. I do always buy the red stuff band and I think it may be made by alto. I just thought if that as I was typing. So maybe they aren't as bad I had read, lol. I prefer borg frictions. Side by side with Raybestos, the Borgs held fluid better. My own testing btw

Understood. I went with Raybestos only because it was part of the rebuild kit through transmission bench hopefully I will get a long life out of them. I don't drive crazy, but I'm not light on the throttle either. I have no qualms about having the pedal meet the floor at times. I'm really enjoying this info it will help in the future!

 

[pwtr02ss]

Understood. I went with Raybestos only because it was part of the rebuild kit through transmission bench hopefully I will get a long life out of them. I don't drive crazy, but I'm not light on the throttle either. I have no qualms about having the pedal meet the floor at times. I'm really enjoying this info it will help in the future!

I have raybestos frictions in my avalanche. Nothing wrong with them at all. They are both excellent

 

[pwtr02ss]

Ok, read the thread from the start. Didn't realize last night that it was already together. Sounds like you covered all the bases very well. IMO, you've got a solid transmission and congratulations on the successful build! I personally feel that if they work out of the gate, they will keep working.

 

[SuperOldSchool]

Nice job! Great satisfaction and learning doing stuff like this on your own.

 

[Timbers68]

Hat's off to you OP for tackling a 4 speed autotrans. Are you an engineer?
Since it's already together and running down the road (congratulations) I'll only comment a couple of things.

Personally I've never used a Zpak since the ones I've seen are putting many thin frictions in place of OE. The ones I have seen have been smoked on tear down. I have not had good luck with long term durability of any Red Alto frictions except Dodge Diesels Autos 46/47/48re. The only reason I used them is because the shop owner liked them. Alto makes some nice red bands for Dodges and they used to make some high energy friction for different units.

Every 700-r4/4L60e I build gets (7) .080" high energy borg warner 3/4 friction with .078" steels. IMO the trick is to get the 3/4 clearance right and not use friction or steels that are too thin (.060"ish) because they can't take the heat. Never used the wide bands on 60/60e's because I've never had a stock width high energy fail. Band disclaimer- not built one of these that was behind much more than 600hp. Using 6 friction with .100" steels is good to go.

I do know that just because I haven't had good luck with a product doesn't mean there's not 50 guys saying the opposite. My .02c

OP, don't through out your case. From the picture I believe you were worried about the indentations that the lo/reverse steels made. Most likely you can clean that up so that the steels won't catch on an edge and use it or sell it.

 

[chevrol8t]

Hat's off to you OP for tackling a 4 speed autotrans. Are you an engineer?
Since it's already together and running down the road (congratulations) I'll only comment a couple of things.

Personally I've never used a Zpak since the ones I've seen are putting many thin frictions in place of OE. The ones I have seen have been smoked on tear down. I have not had good luck with long term durability of any Red Alto frictions except Dodge Diesels Autos 46/47/48re. The only reason I used them is because the shop owner liked them. Alto makes some nice red bands for Dodges and they used to make some high energy friction for different units.

Every 700-r4/4L60e I build gets (7) .080" high energy borg warner 3/4 friction with .078" steels. IMO the trick is to get the 3/4 clearance right and not use friction or steels that are too thin (.060"ish) because they can't take the heat. Never used the wide bands on 60/60e's because I've never had a stock width high energy fail. Band disclaimer- not built one of these that was behind much more than 600hp. Using 6 friction with .100" steels is good to go.

I do know that just because I haven't had good luck with a product doesn't mean there's not 50 guys saying the opposite. My .02c

OP, don't through out your case. From the picture I believe you were worried about the indentations that the lo/reverse steels made. Most likely you can clean that up so that the steels won't catch on an edge and use it or sell it.

Thank you! No actually I'm not an engineer. Just good with my hands. I always loved cars and quickly learned how to maintenance my own vehicles back in the day. Also thank you for your input in regards to your experience with clutches. I opted for Raybestos replacement in my build but did consider the others you mentioned. Yup. Still have the case. She'll stick with me!

 

[chevrol8t]

Nice job! Great satisfaction and learning doing stuff like this on your own.

Thank you! This is a first and I would be lying if I said I was not worried! Glad so far it's working out!

 

[Timbers68]

Thank you! No actually I'm not an engineer. Just good with my hands. I always loved cars and quickly learned how to maintenance my own vehicles back in the day. Also thank you for your input in regards to your experience with clutches. I opted for Raybestos replacement in my build but did consider the others you mentioned. Yup. Still have the case. She'll stick with me!

Raybestos are a great factory replacement clutch too, great choice. I use them regularly.

 

[chevrol8t]

Update: Been driving the Tahoe getting more and more miles under her belt. So far, no issues but I did notice something when I starting getting a lot more aggressive in my acceleration.

I am getting a low vibration when I floor it. It’s a low vibration that increases with speed. The best way to describe it would be like driving on rumble strips but very, very muffled. Normal driving, I don’t feel anything, cruising…nothing but as soon as I mash the accelerator to the floor, I can feel that odd low vibration, like something is out of balance?

A few things to note that after I replaced my transmission, I did replace the torque converter so it’s not factory. It’s a TORCO GM 12.5 300mm reman. Also, I did not change the flex plate. Still the factory 22-year-old flex plate. After popping the inspection plate on the transmission and letting her idle, I did notice a very visible “wobble” during rotation of the flex plate I figure maybe the old flex plate might be the issue Or the replacement converter is not balance correctly?

Not a tranny expert so this is all my speculation. With that said a few things I can confirm;

• Transmission is still shifting great.
• No performance issues…none. No slipping, surging, hesitation. No red flags or concerns (other than the low vibration during hard acceleration).
• No overheating.

Will keep you all posted. personally I don't think it's anything to be concerned about at the moment.