function of front and rear servo on 4L 80e

[Kick3500]

what transmission function does the rear servo controls

and the front servo?
front servo being the one above the valve body in the case

[transbuilderguy]

one applies the front band and the other applies the reverse band.

[PBA]

The rear servo also is the 2nd gear accumulator.

[Kick3500]

thats what I thought

does that accumulator spring affect the 1-2 shift feel.

I asked a separate question for Transbuilder guy (aka TBG) regarding the spring in the 2nd accu,ulator..... would going back to the stock spring instead of the spring supplied with the transgo kit soften the 1-2 shift on a 4l80e.?

[transbuilderguy]

stronger springs gives a softer 1-2 shift weaker spring gives a firmer 1-2 shift

[Kick3500]

thanx
thanx

think I will put the stock spring back in the accumulator..

trans had a intermittent problem with the TCC dropping out sometimes.... had pulled pan with intention of replacing TCC spool valve and PWM solenoid with a Sonnex kit with the upgraded spool valve... not knowing I had to pull the valve body in order to remove the roll pin... just replaced the PWM solenoid the first time..

to make along story short, I decided if I had to pull the valve body, I might as well put a Transgo shift kit in it.. set it up at the soft settings, but the 1-2 shift is a bit hard for my tastes.

its Ok at real light throttle angles and OK at half throttle or above but medium throttle it shifts harder than I like..

so I think I'll swap back in the stock spring and see what happens..

as it is I can live with it, but I'd prefer it was a bit softer on the 1-2 shift..

gotta say its amazing how much quicker it shifts ranges with the kit installed

also cant imagine why anybody would desire the higher shift settings..

[oldred95]

also cant imagine why anybody would desire the higher shift settings..
Me either but it depends on what torque converter your using. The higher stalls soak up the shift feel like a sponge. Mine stalls very very low and is very tight and I set mine with the "normal" settings and the 1-2 is just brutal but I like it that way. It hits so hard the whole truck torques to the right and it sling shots itself forward. At part throttle its a pretty nice firm nudge but past say 25% throttle it starts getting mean.

[transbuilderguy]

The 4l80e really doenst need less accumualtion as other units do to make a shift due to the hydraulics of the 4l80e and the th400 they have large apply the best thing to do is open the feeds to the clutch as in this case the intermediate clutches on the 80e