shifting problem 4l60e

[dian]

this is on a 99 c5 running 1 bar of boost.

i had the 2-3 upshift set at 6200/124 kmh last year. i took the car out the second time this year and it wouldnt shift, i ran into the limiter set to 6400 and saw over 6600 rmp. i did two logs like that and quit (i didnt like the 6600 at all). i lowered the shift point to 5800/118kmh and the trans shifted. i raised it to 6100/118 and it shifted. the next day it wouldnt shift any more. im sick of running into the limiter, the belt jumps a rib.

so, is the trans giving up the ghost or can that be some programming issue? (the first outing this year was just to check on the mixture, i made one pass to 5600, so i dont think it killed the trans.)

[joecar]

Post tune file.

Is tire/gear/speedo all correct...?

[dian]

i did the transmission tuning two years ago and didnt touch anything since then except the 2-3 rpm. it always worked. in the meantime i lowered it to 6000/118 and it shifted. it almost looks like it shifts after a change and then quits shifting after a couple of passes.

frankly, i forgot how to post files, i will try and remember.

[dian]

so i managed to post the file. you will see some weird things in the trans tune, thats how iv had it set up for two years.

so yesterday i set the 2-3 wot shift to 6100/118 and it shifted. today i made another pass and it shifted below 5900, 5929 being the highest rpm recorded.

[joecar]

Are you saying it was shifting ok for 2 years and then now it suddenly does not shift after a few times...?

[joecar]

Try this:
- lower D0935-7 from 130 mph to 120 mph.
- lower D0908 last cell (TP 100%) from 130 mph to 120 mph (same as D0935-7).
- set D0920-2 to 133 mph (same as high cells in D0902).
- set D0960-2 to 100% all cells.


Your WOT 3->4 upshift MPH is close to 6000 rpm... try pulling it down to say 125 (do this in D0920-2 and D0902), and then creep up on 133 mph.


Are you running a shift kit, if so, which one...?

[dian]

exactly, trans did what i wanted for two years and quit shifting properly from 2-3 the first time i made a pass this year. no shift kit, everything stock. i will look into the stuff you mention. (i dont worry about the wot 3-4 shift, i have never done it and probably never will, unless i take the car to germany, but thats a long drive and another 100 km or so until the autobahn opens up. 120 kmh on the freeway here.)

edit: i see the first 3 points concern the 3-4 shift. my values are the same as a stock tune. i never touched them. should i do all this to the 2-3 shift perhaps? d0960-2 are 100% in the stock tune indeed. the problem is my tp only goes up to 99.6%.

what i will do is set all trans values to stock and see what happens.

[joecar]

Ok, try the same concept on the 2->3 shift.

Also try stock, like you said.

Log these pids:
SAE.VSS
GM.ETCTP
SAE.RPM
SAE.ECT
GM.TFT
GM.TOS
GM.TIS
GM.TCCMODE
GM.TCCSLIP
GM.GEAR
GM.TFMPRS
GM.TRQENG
GM.SHIFTLAST
GM.SHIFTDELAY
GM.TPSSHFT

[dian]

so im back to this.

while i had no problems tuning the engine (it still lives) i know nothing about transmissions or converters. my research has yielded the following (and please correct me if im wrong):

- my transmission is very marginal behind 1000 nm of torque
- the converter clutch is constantly slipping. thats hard to believe but seems to be the case
- the max line pressure (if thats the correct expression) cant be increased with the software, its 90 psi.

http://www.sonnax.com/tech_resources/214-20-years-later-what-s-new-with-4l60-e-pwm-modifications

so the clutch has been slipping for two years behind 1000 nm now and may very well be toast. i had relied on the "base tune" i got and because the part time shifts firmed up somewhat i was led to believe it was o.k. at wot also. not so apparently. so i took off the blower and decided to get a hold on the trans n/a first.

here are two loggs, the first one (7) has tos and tis in it. i dont know what to make out of it. tcc slip is negative at wot. so either the input shaft speed is incorrect or my converter not only multiplies torque but the speed by some miracle as well. what am i missing? how can slipp cross zero during a wot pull?

i understand "release" and "apply" are essentially the same, its the state of slipping clutch. why do they occur when d 1001 and d 1004 are set to max? how to get ridd of them and keep the converter off all the time? or at least during wot? 1002 is set to 80% throttle. the 1-2 shift happens under apply.

i see a lot of inconsistencies in whats happening. I probably need a lot of education on this.

[joecar]

I'll look at your files and report back.

What is the color and smell of the fluid in the trans...?

~ posted by phone ~

[dian]

no idea about the fluid. i will suck out some next week.

i see that release occurs when there is a transition from lock to apply. i see instances where it goes directly from lock to apply, however. i have also been thinking that d1004 is wrong at 412 and should be zero or below apply, but then ist set to 412 in the stock tune. d1007 is 100% stock, btw.

what i would do first is to set d1007 to max from 400nm. but for boost that probably is irrelevant, because torque is higher. well, i was not logging engine torque i dont know where it comes from. is it a calculated value using the ve table as one of the inputs? then it would be based on values you put in there. now its pretty close, engine is rated 480 nm at 4200 rpm. i was logging rwhp on boost and it was a little low but not unrealistic. but maybe that gets calculated from the real acceleration?

anyway, here is a couple of logs boosted:

looking at 9.1 at the last two passes, it stays in apply until 5500 and is off in the other. the same in 8.2.

(at this point im only really interested in the 2-3 shifts. first gear is useless when boosted and second takes me to around 150 kmh, 120 being the speed limit. i dont think the car has been above 4500 rpm in third, since i have it.)

desired times are zero, so tap (trans. adaptive learning) should be gone, at least i hope so. could i set p0101 to yes and make the trans run at full pressure all the time? didnt you say somewhere that setting shift times to zero and deleting torque reduction would make the shifts "brutal"? well, my shifts are soft, even n/a. under boost the 2-3 shift takes 0.6 sec. (measured from highes to lowest rpm, disregarding what actually happens in the trans).

[joecar]

1000 Nm (730 ftlb) requires a specially built 4L60E or 4L80E and a multi-disc TCC.

The line pressure would need to be increased by mechanical means in the special build.

[joecar]

TCCSLIP is meaningful only when TCCMODE indicates Locked

( when not Locked, the slip may not be updated properly, especially with the 4L60E which has no ISS sensor )


Negative slip means the transmission is going faster than engine... which is interesting as you have noted.


Yes, avoid locking the TCC at high throttle (say above 80% TP).

[joecar]

Set D1004 to a large (un-achievable value) below D1001.

TRQENG is calculated by PCM based on dynair and spark.

RWHP is calculated from vehicle mass and change in VSS.


Have you scaled VE/IFR...? If so then trans line pressure will be low... you can mechanically increase pressure by turning set screw on PCS say 1/8 th turn (mark it first).

Do you have a 300 psi pressure gauge to monitor the line tap on the side of the trans...?

Yes, shifts should be very firm and quick (should chirp and/or break tyre traction)... try setting shift times to 0.2 second.

[dian]

you mean to set shift times to 0.2 from 0? d1001/4 are at 412. so i set d1004 to 411?

what is iss? tis is larger than engine rpm during a pull. what do you make of that? o.k. iss = input shaft sensor? there is none? you made my day. so i dont worry about that anymore if its not there, right?

the real question is: how do i keep tcc off at all times? (i have read a lot of stuff and my head is spinning. a lot of controversial info too.)

[joecar]

Set D1004 to be lower than D1001 (not equal and not higher).

4L60E does not have input speed sensor (iss)... so in this case the PCM calculates TIS... so TIS only makes sense while the TCC is locked.

To keep TCC off simply set the apply curves to unachieveable speeds...

but TC generates a lot of heat while TCC is unlocked, you will need a bigger trans fluid cooler.


~ posted by phone ~

[dian]

so in the above tune i moved the 1-2 shift point from 4000 to 5800, set 2. release from 412 to 400, the 1-2 pressure to 600 above 400 nm and the 2-3 pressure to 662 above 400 nm. car went a little sideways during the 1-2 shift but 2-3 was not much different. tcc is unlocked and applies around 5300 in first and stays there during the shift and untill 5400 in second. in the x7 log in appied at 3600 and went off at 5800. so i dont know. it should not apply in second and in no gear at wot. since there is no table for first, i have to assume it never applies in first but it does. i have been reading on here and on other forums and everybody sais the same, work with the tp/speed tables.

i logged tccdc and its either 0 or 100 as expected but it has no correlation with tc mode. cant logg tccp.

either the logging is not correct or the trans is crazy. im tempted to wire the brake switch to see what will happen. thats the only way i can think of to gain controll over the tcc. its doing what it wants.

btw, i cant feel the tcc engaging and have yet to experience a chirp from the tires (275/49718). the fact that a lot of members complain about harsh shifts really gets me.

edit: i worked my way to h0102 (outputshaft revs per km). its 11.6953 in the tune. its different by 8% in the original tune and again that much off the other way in a 99 c5 tune i found. where do the fractions come from. mine is pretty close with 2.065 m per tire rev.

its dawning on me that the tc might be locked all the time exept at idle (tccdc) and tcmode is a ghost reading. is that possible?

[joecar]

...

its dawning on me that the tc might be locked all the time exept at idle (tccdc) and tcmode is a ghost reading. is that possible?Possibly...

I'm thinking about how to diagnose this...

[dian]

here is another logg, if somebody wants to have fun and study that. you see me stepping on the brake, like frames 3500-4000. tcc unlocks.

(the forum seems to have changed into an "ask joe platform" now.)

[joecar]

( lol, I'm an intense car guy )

I'm looking thru your log... I'm analyzing the ratio of TIS:TOS, RPM:TOS and RPM:TIS

( see attached calc_pids.txt, rename it to C:\users\<you>\Documents\EFILive\V7.5\User Configuration\calc_pids.txt ).


For next log:
- remove the pid GM.TCCP (this is not for 4L60E/4L80E)(it gives strange values)
- add the pid GM.BOXRATIO