3-4 shift on a 4l80e Q?

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01-14-2006, 01:56 PM

#11

moregrip

what a rush!

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Quote:

Originally Posted by James B.

I used 0.086" for Second (C) and Third (B), and used the 0.096" drill bit for Fourth (A).

You might consider drilling hole (A) out to 0.120".

gotchya, thanks, I need another tranny fluid bath anyway

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01-14-2006, 06:39 PM

#12

parish8

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Quote:

Originally Posted by James B.

The 4L80-E can do WOT shifts. On my truck the WOT 3-4 takes place at about 99mph, so I have frequent opportunities to do it.
My trans was rebuilt with a Level 10 PTS kit before I installed it. At the time there were no 3-4 clutches available with high performance friction material. I'm just running stock replacements on it. I made the fourth orifice larger to make up the difference. This worked well. Another guy that rebuilt his own 4L80-E did the same thing based on my experiences and got good results also.
There are now Blue Plate Special performance clutches available for Fourth and its overrun packs. This goes for about $75. The next time my trans is apart it will be getting a set of these.

what gears do you have in that thing? i dont think i would need 4th till 150+

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01-14-2006, 07:51 PM

#13

James B.

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Quote:

Originally Posted by parish8

what gears do you have in that thing? i dont think i would need 4th till 150+

Gears are 4.56:1 with 30.4" tires. I'm shifting at 5300RPM limited by the supercharger redline, already exceeded by 10%. It's still a 100% stock bottom-ended Vortec 350.
I have a Gear Vendors Overdrive behind the 4L80-E and use double-overdrive on the highway going over 60mph. Trans ratio in double-OD is 0.59:1 and engine to axle ratio is 2.71:1 in double-OD. It actually cruises at about stock RPM.
I do worry about my driveshaft RPM. I have been to 125+mph a few times but it's hard not to think about the driveshaft doing 6300RPM at that speed.

Last edited by James B.; 01-14-2006 at 07:58 PM.