Kano

iTrader: (3)

logging transmission for slipping


what do you log and what do you look for after
you log?


Ive seen the fluid
dark and burnt
dust caked all up on the magnet

Im sure its seeing its last days of life

just wanna know what to log and what #s the problem is at
for future reference

Kano

iTrader: (3)

TTT

this ? should be simple for some of you

horist

you can log
input shaft speed
output shaft speed
Torque Converter Slip Speed
Current Gear
TCC Mode

you can then calculate transmission slip by taking the input speed, and figuring out what the output speed should be (assume 0 converter slip right now) (depends on current gear)

Now you subtract converter slip from that and you should see how much the actual trans is slipping... would be even easier when the TCC Mode indicates the converter is locked in 3rd gear since it's a 1:1 relationship (3rd gear w/torque converter locked, you should have identical input and output speeds)

If a trans is toast or slipping bad enough you'll also notice WOT that it'll bounce the rev limiter since the clutches can't engage (usually 2-3 shift on 4L60Es)

also you can monitor trans temp... a slipping trans generates alot more heat...

Burnt fluid though... trans is definetly on borrowed time... bottom of trans pan most likely has a coating of clutch material on it as well...

Kano

iTrader: (3)

ok what does tcc mode mean
it says off thru 1 and goes to --3-- in second + third

when you say calculate
do you
example... input rpm/3.06
for 1st gear
how about tcc slip I see 80 to 157% slip
or 200 to 1000rpm slip

Kano

iTrader: (3)

is it
input rpm/trans gear ratio-tcc slip
or
input rpm-tcc slip/trans gear ratio

calculate this for me if you dont mind
input=1667.8
output=545.3
tcc slip=607.8
1st gear
tcc mode off

Kano

iTrader: (3)

oh and thanx for the responce

horist

trans receives input speed (aka engine RPM)

Torque converter is either locked (0 TCC slip RPM) or slipping (slipping anytime it isn't locked)

you apply gearing and result in an output shaft speed


output shaft speed depends on input shaft speed , torque converter slip... and gearing.....



3rd gear?
gearing - 1:1
if TC locked then slip = 0
input shaft = 6000RPM .. output should be 6000RPM .. if the converter is slipping 50RPM while locked then output should be 5950RPM

part throttle... converter unlocked... it can slip a ton...

input 6000RPM.. TC slip =2000RPM... output shaft speed should be 4000 RPM


to determine WOT slip %


Rear tire height = Pie D (same as 2PieR) as a circumference ... this is inches per revolution...


output shaft speed /rear gear is speed per 1 revolution .... so output/rear gear * Pie D is the distance travelled in x time .. since RPMs are in minutes... then x is minute...

so inpout speed vs max theoretical output speed vs actual theoretical speed compared is your % slip ....