LI Steve

My 4-speed auto was feeling a little lazy, so I installed a parallel kickdown switch yesterday. Can you say "Dr. Jekyll & Mr. Hyde"?

I was under the impression that it would just hold each gear a little longer while under mild throttle (maybe 4k RPM while at 30-50% throttle), but it seems to hold each gear (well - 1st and 2nd at least) all the way to redline.
Does anyone know what other factors are considered (e.g., throttle position, load, etc.) in determining an upshift?

Thanks!

Thaddeus

They work nice, don't they?

IcemanG17

Steve
So with the switch "on" and about 1/2 throttle..it will hold 1st and 2nd all the way to redline, even at the 1/2 (or less) throttle? I thought it was just supposed to make the kickdown happen faster, especially in less than full throttle situations? Maybe your bowden cable is too tight? Did the trans shift/kickdown normal before the parallel switch?
Brian

pappy92651

A lot depends on the valve body and model year. My (not MY) 89 holds all gears until redline. If I manually select 2nd it will stay in 1st from a standing start until I hit the rev limiter. Some of the 87s will shift to second automatically before redline. The kickdown will occur earlier and hold longer if the bowden cable has more tension. It is also possible to retune the valve body to down shift early into 1st gear at speeds up to 45 MPH. If you change the shift program by any of these means you should consider using synthetic ATF to reduce temperatures and wear. If you are slamming the gears a lot you should consider installing AMG hard parts ($7000.00). Damaging wear occurs during forced downshifts and extreme engine braking. The stock AT design is extremely robust when used for sequential up shifts.

Tony

cool picture!
do you have any more of the 4spd guts for giggles

pappy92651

I'm sure I do. If we were to hold a blow up your AT contest I'm sure I would place. It's an expensive club to join and you have to be dedicated.

I'm putting the new side plates on the intake soon. Louie says that my 1st torque peak will come on real strong. Ahhhh, I can smell fresh parts on the way.

My big speeding ticket was dismissed. I'm back!

LI Steve

Brian - Yup. Even if I am only at 15% it will not upshift out of 1st or 2nd with the switch on. When I completely let off of the gas, it seems to go into neutral (revs drop to about 900), and as soon as I get back on the gas, the revs shoot up. I guess I will have to check my bowden cable, but I am not sure what 'normal' is, since this is the only auto 928 I have ever driven. I can tell you that when the switch is off (and before the install), the trans would upshift very soon at partial throttle, and was quite reluctant to downshift at all until I hit the switch under the pedal. Is that 'normal'?

Apoc

Hmm, in my 3 speed 79, under partial throttle 50%-75% I usually go all the way up to 4000-4500, but to get it to kick down by itself once its changed up at anything like above 3000 it's usually a fairly heavy push on the throttle. However later MY will behave very different, being a 3 speed mine always starts off in 1st, unlike later MY AT which start off in 2nd. If I hold it in 2nd and take the revs up to a decent level (say 3000-4000 again) and take my foot off the gas it will do as yours and seem to go into nuetral and idle around 800, leaping up as soon as I put my foot back on the gas, so in that way it is identical.

Don't know if this helps much, being a much earlier MY.