Another 2-3 flare question..
Another 2-3 flare question.. Ive searched around a seen a few things but would like to see if someone could answer a couple things for me.
I have a 2003 Chevrolet Tahoe LT 4x4. Stock with 236k on it. Trans recently slipped 3-4. The guy I bought it from gave me another transmission from a 2wd 2005 Silverado. I had the output shaft swapped and a couple things done internally. I was told the trans only had around 50-60K on it and the trans guys told me it was a very clean piece inside and all should be fine. I wanted it to hold a little more power so they said I would be fine with a beast sunshell, new borg warner band, and a raybestos z pack for 3-4.... so I said okay. He said it would be better for towing capacity if I decide to due to the fact that they dissipate heat better. They assembled it and off I went. I put the trans in and got it going. Drove fine for a couple days them I noticed it had a somewhat rough 1-2 shift then it had a 2-3 flare. Wasn't too noticeable at first but then I started to notice it more. Ive only put 75-80 miles on it. Had the builder drive it and he said it needed a couple things. He suggested a sonnax boost valve in the pump, the sonnax 2-3 shift valve install, and a shift improvement kit with different separator plate.
I've read some threads that say it should fix the problem but here is a big question I have. I've read that 3-4 clutch pack clearance can cause a 2-3 flare... or at least that's my understanding. I was there when they assembled my trans and they put the raybestos z pak in and checked it by just pushing down, no feeler gauges.... He said they include another thin steel plate for tighter clearance but he didn't use it. I believe he said they say .050'' or something like that. It makes me wonder about it due to the fact that others have said to set the z pak at a tighter clearance than raybestos suggests.
I don't have a lot in the transmission right now (less than $400 with the new parts he suggested for the 2-3 flare) but don't want to keep putting a lot of money and parts in it hoping to fix it. I should have just ordered a complete rebuild kit to begin with.
Any help will be greatly appreciated.
Thanks,
Eric
I have a 2003 Chevrolet Tahoe LT 4x4. Stock with 236k on it. Trans recently slipped 3-4. The guy I bought it from gave me another transmission from a 2wd 2005 Silverado. I had the output shaft swapped and a couple things done internally. I was told the trans only had around 50-60K on it and the trans guys told me it was a very clean piece inside and all should be fine. I wanted it to hold a little more power so they said I would be fine with a beast sunshell, new borg warner band, and a raybestos z pack for 3-4.... so I said okay. He said it would be better for towing capacity if I decide to due to the fact that they dissipate heat better. They assembled it and off I went. I put the trans in and got it going. Drove fine for a couple days them I noticed it had a somewhat rough 1-2 shift then it had a 2-3 flare. Wasn't too noticeable at first but then I started to notice it more. Ive only put 75-80 miles on it. Had the builder drive it and he said it needed a couple things. He suggested a sonnax boost valve in the pump, the sonnax 2-3 shift valve install, and a shift improvement kit with different separator plate.
I've read some threads that say it should fix the problem but here is a big question I have. I've read that 3-4 clutch pack clearance can cause a 2-3 flare... or at least that's my understanding. I was there when they assembled my trans and they put the raybestos z pak in and checked it by just pushing down, no feeler gauges.... He said they include another thin steel plate for tighter clearance but he didn't use it. I believe he said they say .050'' or something like that. It makes me wonder about it due to the fact that others have said to set the z pak at a tighter clearance than raybestos suggests.
I don't have a lot in the transmission right now (less than $400 with the new parts he suggested for the 2-3 flare) but don't want to keep putting a lot of money and parts in it hoping to fix it. I should have just ordered a complete rebuild kit to begin with.
Any help will be greatly appreciated.
Thanks,
Eric
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Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Based on the feedback from many builders, I am not a fan of the Z-Pak as they tell me it won't hold 400+HP as well as other setups. However it should also not flare (fail?) as quickly as yours did. A builder who says he installed hundreds of Z-Paks (before switching to 8x BW HiEnergy) said that the .050 clearance was a MUST; if you tried to install with less clearance, the frictions would quickly wear (out) until the .050 clearance was achieved.
Everything your builder is now suggesting (Sonnax boost valve, HD 2-3 shift valve, new separator plate drilled according to a shift kit) are all good and recommended. I do fear that the Z-Pak is already damaged, but perhaps that additional parts will cure the flare. I find it a troublesome that the builder did not measure the clearance, especially when the Z-Pak instructions emphasize the importance. Personally I believe that most almost-immediate 3/4 clutch failures are due to leaks in the 3/4 apply circuit due to hasty assembly.
Everything your builder is now suggesting (Sonnax boost valve, HD 2-3 shift valve, new separator plate drilled according to a shift kit) are all good and recommended. I do fear that the Z-Pak is already damaged, but perhaps that additional parts will cure the flare. I find it a troublesome that the builder did not measure the clearance, especially when the Z-Pak instructions emphasize the importance. Personally I believe that most almost-immediate 3/4 clutch failures are due to leaks in the 3/4 apply circuit due to hasty assembly.
