First post, yay.

So I guess the best thing to tell you guys first is whats in this transmission:

2000 4l60e
9.5" Yank 3600 Converter
Sonnax Smart Shell
5 Pinion Front and Rear Planets
Kevlar Wide 2-4 Band
Sonnax 2nd Gear Super Servo
Sonnax 4th Gear Super Servo
Sonnax HD 2-3 Shift Valve (over run clutches on in D3)
Sonnax Performance Pack (Accumulator Springs and Pinless Pistons and Servo Check Valve)
All Clutches are Raybestos Stage 1's with kolenes except 3-4
3-4 Clutches are Raybestos Blue Hi-Energys @ .050" clearance

This transmission has taken tons of abuse and held up well. When I first built it I was very satisfied but it never really shifted as firm as I wanted. So I drilled the separator plate and now the shifts are all f'd up haha.

Feed holes which worked but weren't firm enough:
2nd: .093
3rd: .093
4th: .093

Here is what I drilled them to with hopes of tire barking shifts:
2nd: .125
3rd: .125
4th: .125

So now it shifts crisp and firm in all gears but only at 1/4 throttle. As soon as I go into 1/2 or more throttle the shifts become slow and soft. So tell me why drilling the plate resulted in firm shifts only at part throttle?

NOTE: This trans has the Sonnax check valve which I drilled the orfice to .125" per instructions.
EDIT: Forgot to add it also has transgo Hi RPM 3-4 release springs.

 

Check Line Pressure! 2nd should thump pretty hard with a .093" 2nd feed & Sonnax 2nd Servo.

 

Right. You need to make sure line pressure is going up with throttle position.

 

Did some testing today and the 1-2 at WOT is delayed and some what firm, the 2-3 at WOT is instant and very firm. Have not had a chance to test line pressure yet because I need to get a hose and guage.

 

Checked line pressure and it was consistently 150 psi at WOT, it would spike to 200 psi at 1/4 throttle but as more throttle was added line pressure dropped to 150 psi maybe lower on hi rpm runs. Before I got home it lost 3rd gear.

 

Pressure shouldn't drop, 200 is adequate....But should stay there at WOT.

Fluid level is OK???? I fill too the Max Hot mark with the unit Cold. 1/2 Quart over.

Did you install the "Pump Parts"?? Boost Valve & Primer Spring.

What shape was the Pump in??

What pan are you running? Good/Correct Filter installed? I use OEM SPX/Filtran.

Data Log the EPC, TPS, MAP, MAF.

 

Fluid level is exactly the same as you run your transmission.

The pump has the .490 boost valve and spring, heavy pump slide spring.

Pump is in excellent shape.

The pan is a deep pan from trick flow, comes with an aluminum extension tube to run stock filter which is brand new. Every time i pull the trans i replace the filter.

I am suspecting the tune has some issue or the EPC is fouled up.

Also the truck has a speed density tune on it.

 

I like to see 235psi. - 240psi. Max. at WOT, with 220psi. the absolute minimum. Disconnect the wire connector from the transmission and see what pressures you have. This will put it into limp mode and you should see maximum pressure here. If the pressure is close to what it should be, then the computer is telling the pressure to drop, and you need to find the reason in order to solve this. Once the computer problem is solved and if the WOT pressure is still a little low, then you can adjust the EPC solenoid to get the right needed pressure. If it is way off (not common) then the SPC solenoid should be replaced.

 

This is a good thread showing the importance of testing with a pressure gauge.
Especially when a newly built trans (whether by the owner or a shop) is acting up.

Clinebarger and PBA (both pros) have you well covered.

 

As soon as I got home I disconnected the wiring harness main plug and hello pressure. I was seeing a full 230~240psi, sucks I have to pull the trans back out now to replace the 3-4 stack.

PBA, I was thinking when I tore into the trans this next time taking the input drum and removing the input shaft to apply some sleeve retainer. I already have the input drum reinforcement kit from sonnax.

What are your thoughts on the Smart-Tech Input Drum? I like the thought of more clutches with thicker steels to dissipate heat, but I read in another thread where you said the friction materials ability to retain fluid is what keeps the clutch pack cooled down and also you said that coning of the clutch pack isn't as bad as everyone makes it out to be. Thoughts?

 

Purchased a Sonnax smart tech input drum, got some sleeve retainer. Frictions and steels will be here next week so I will probably start a new thread with pictures of the rebuild, who cares right? But I figure some people would like to see because this input drum is sexy

 

I'm game for a rebuild thread