trans pressures
need some advice on setting trans pressures d0701,d0702,d0703
pressures weren't an issue until i herd strange noises from my 4l60e i got the box stripped and found all clutches buckled and worn including 2nd band?
so $4500 dollars later my trans repairer thinks it could be the maggie or through program i haven't altered any pressure settings. still factory settings only shift at vss due to 3.91 installation
Last edited by drdarthinvader; November 24th, 2009 at 02:08 AM.
Ouch that repair bill does hurt...
The clutches got buckled from being overheated... they got overheated from slipping... they got worn from slipping...?
How much torque/power can your engine make...?
How many km were on the trans when this was detected...?
Either:
- engine makes more torque the trans capacity,
- PCM is not calculating the correct engine torque.
The 2nd item above becomes important when the MAF and/or VE tables are too low... in your case, the PCM is running in SD... you have to monitor GM.DYNCYLAIR, GM.TRQENG, GM.TFMPRS... the PCM uses the 1st to calculate the 2nd, and uses the 2nd to calculate/lookup the 3rd...
Tables D0701,2,3 are active during shifting... at other times the PCM calculates/looksup the in-gear base pressure based on TRQENG (but I never seen those tables in any calibration).
Your D0701,2,3 do appear low to me... I like to make a staight line from zero to 80 psi, at 369 ftlb, and then continue on up to 90+ psi...
Reduce your shift times to 0.25s.
Increase shift torque reduction, this will also help to protect your trans from breakage and sudden slipping during a shift.
The PCM calculates/looksup TFMPRS to control the PCS solenoid... the PCS solenoid regulates Torque Signal pressure which assists (via the boost valve/spring) the pressure regulator valve in increasing line pressure... if there's any problems with line pressure (i.e. problems PCS solenoid, the boost valve/spring, pressure regulator valve, the pump and slide mechanism, or if line pressure is internally leaking) there will be slipping.
When being rebuilt, your transmission needs upgraded parts, including a performance band and clutch plates, and extra clutch plates. If you have a stall TC then you need a suitable cooler.
Also, religiously check your fluid level and colour/condition everyday, and change fluid/filter every 15K miles.
i just found out the forward clutch piston seal had a large nick in it and had rough machine work from factory,the clutches buckled from slipping but no clutch material in the bottom of the pan and no worn hard components ?
the engine produces around 400hp std cam ls1,heads maggie boostin 155kpa and the transmission has done 105k with regular oil changes and large trans cooler installed plus had a stage 2 b&m shift kit installed ..
i dont put too much faith in std 4l60e to handle any significant engine mods but will respond well with tougher parts installed.
Ouch... poor OEM quality control...
The nicked seal would have let the forward clutch slip (in all forward gears)... if the clutch friction plates are high quality then they glaze without breaking off... hence no friction material in pan... the plates glazed without wearing thru (i.e. no metal-metal contact), hence no metal in pan...
Also the filter was not clogged with friction material, so lube was good to all bearing surfaces and gearsets, hence no signs of wear on hard parts.
When the clutch plates slipped they generated heat which glazed the plates, which in turn would allow more slippage, which in turn generates more heat... when the heat became excessive the plates would have progressively warped... also the fluid would have looked/smelled burnt.
Would you say the noise was the forward clutch slipping (whining) or the clutch rattling (warped plates)...?
400 rwhp... would that be about 460 fwhp...?
400 fwhp is the upper limit (non-conservative) for the stock 4L60E.
Yes, the 4L60E has available many performance parts and responds well to mods.
defiantly clutch rattling (clutch shuddering),the engine would prob produce about 400fwhp..
also i would like some advice on setting tcc lock up stages for normal mode and performance . ive got this order> downshift, tcc rel, upshift, tcc app would this be correct? just wondering if the trans xls can be altered to incorporate another graph with all shift points and all tcc stages on the one graph would be handy,
If you have plenty of low end torque you can allow:Originally Posted by drdarthinvader
- PT upshifts to be early,
- PT downshifts to require large TP,
- PT TCC to lock early (better fuel economy),
- PT TCC to stay locked longer;
You can set the upper end of those tables to do the opposite (upshift/lock later/shorter)...
The WOT tables will take care of WOT (and TCC is unlocked at WOT).
Start with the stock PT up/down shift and TCC lock/unlock tables and adjust up/down from there to get good "feel"... i.e. avoid hanging on to a gear or short-shifting into the next gear, and TCC should lock when cruising or accelerating below medium load...
I'll play with with the spreadsheets next week.
ive just installed the new trans but im getting large plateau in tfmprs during up shifts and also shuddering during acceleration ive disabled tcc for now till i get the shift pattern more stable any help would be appreciated
Log GM.TRQENG instead of GM.TRQTRANS so you can see the link into the pressure tables.
You might have adaptive shift learning kicking in... you can try setting the shift times to zero.
i found out the problem a fouled spark plug..it was creating a shuddering effect on the drive train which i thought that the new transmission was to blame. ive o all desired shift times and applied tcc only on normal cruze 4 gear only.changed the whole vehicle.
Last edited by drdarthinvader; December 26th, 2009 at 10:56 AM.
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