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4l60 problems

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Old 02-28-2008, 07:49 PM
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Default 4l60 problems

99 Z28 4l60 trans. 3rd gear slipps

1,2,and od are ok, when it shifts into 3rd rpm goes up???
new built trans, think prob is in trans but want to make sure.
any help or input would be greatly appriciated
Old 02-28-2008, 07:51 PM
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Freshly rebuilt ? Like low milegae rebuild ? Wonder if someone left out the springs in the 2-3 pack and its been chewing it up with centrifigual apply ?
Old 02-28-2008, 07:54 PM
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it's my brother's car, he blew third gear out about 6months ago, and
the trans hasn't worked since, about 50 miles on trans, i'm a car guy if you will, but know very little about this trans. and don't want to take it apart for
fear that the shop that built it will blame the problems on me
Old 02-28-2008, 08:01 PM
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Originally Posted by LS1curious
Freshly rebuilt ? Like low milegae rebuild ? Wonder if someone left out the springs in the 2-3 pack and its been chewing it up with centrifigual apply ?
There is no "2/3 pack".

There is a 3/4 clutch pack that is applied when the unit is in 3rd and 4th gears respectively.

Does it flare at all throttle positions... meaning normal driving and at Wide Open Throttle? If so, then I am afraid there is an inssue in the 3/4 clutches themselves or an issue with the 3rd gear accumulation losing hydraulic pressure.

Either way, it is internal. The unit needs to come out and be gone through by a professional who knows these transmissions.

g
Old 02-28-2008, 08:04 PM
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od/4th gear is ok, if that helps
Old 02-28-2008, 08:12 PM
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For some reason I am thinking of a different unit. Yes there is no 2-3 pack . Would sure as hell go a long way to fixing that unit to. I agree must come out and be gone through .

Originally Posted by Ratchthed
There is no "2/3 pack".

There is a 3/4 clutch pack that is applied when the unit is in 3rd and 4th gears respectively.

Does it flare at all throttle positions... meaning normal driving and at Wide Open Throttle? If so, then I am afraid there is an inssue in the 3/4 clutches themselves or an issue with the 3rd gear accumulation losing hydraulic pressure.

Either way, it is internal. The unit needs to come out and be gone through by a professional who knows these transmissions.

g
Old 02-28-2008, 08:13 PM
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It does help and thanks for that comment.

Here is why it can feel good in 4th but slip going into 3rd..... During the 2-3 upshift the Band is released and the 3/4 Clutches come on. During the 3-4 upshift the Band comes back on, the 3/4 Clutches stay on and the Input Sprag releases.

So, The idea is that if there is excessive clearance in the 3/4 clutches or there is poor hydraulic feed during the 2-3 upshift we will not feel a difference in 4th gear. We might see a problem in 4th over time if the clutches are not stacked corretly.

Hope that helps.

g
Old 02-28-2008, 08:29 PM
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thanks for the help, seems like i need to get a manual for this trans.




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