what exactly is a servo and is there one for the 4L80E?

 

The servo is a shift selenoid AFAIK and controls line pressure in the trans during the shift. There are two in a 4L80E. I am not an expert so maybe someone will confirm that my understanding is correct.

 

Ya I am also interested in this along with putting a transgo shift kit in my 4l80e. I haven't seen anyone who makes servos for these trannys, only the 4l60e.

Alex

 

i thought that the servo's were the part that applies the bands in the trannies. not a solenoid. they are on the side of the case. i dont think that updated servos are needed for an 80e. i have a built 80e and i believe that they are the stock servos in it. if you put in a hd trans go shift kit then go to the 96 on the holes or i beleive the 84 setting. mine are at 96 and when she shifts--SHE SHIFTS

 

I was under the impression that the 4l80e did not have an external servo like the 60 has on the side of the tranny. O, and on another note, actually how bad is the first gear ratio on the 80e, will it be noticablely slower taking off than a 60.

 

02's right ... the servos apply the band in the 60e. SInce the 80e doesn't have a band, it doesn't have servos.

Technically, it DOES have servos, but not the ones that your thinking of on the side of the 60.

 

flyer, did you notice a difference in the take off, or like loss of torque in first gear compared to the 60e? i've heard the first gear is a pig on the 80e, JW?

 

Actually, the 4L80-E has two bands exactly like a TH400. The front band is called the manual 2-1 band and it to prevent overrun. It is used only when the selector is in "1" or "2" and only when the trans is physically in second gear. The rear band is used only when the selector is in "1" and the trans is physically in first to prevent overrun. The rear band is also used for reverse.

In a 4L60-E there is only one band but it handles normal shifting (second and fourth) which is why changing those apply pistons changes shift characteristics.

 

yay that is what i was trying to say

 

I stand corrected.

Good info James.