Mooseman
Moderator
Yes, you need either a tech 2 or other scanner capable of resetting the trans adapts.
The shifts sound about right to me for towing. The 4.2 is a higher revving engine so it's torque curve is higher.
JayArr's 4l60E Rebuild Thread
- Thread starter JayArr
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The shifts sound about right to me for towing. The 4.2 is a higher revving engine so it's torque curve is higher.
FWIW, the TAP parameters are stored in data blocks. When a Tech 2 clears these learned values all it does is write zeroes to data blocks 41 through 49. The Tech 2 will caution the operator that this is only to be done after an 'internal repair' of the transmission.
Given proper instruction of how to do it one can even do it with the current version of Torque Pro using the direct control option in the Torquescan OBD Terminal feature.
I confirmed this today with a 2005 PCM here in my corral of parts.
Given proper instruction of how to do it one can even do it with the current version of Torque Pro using the direct control option in the Torquescan OBD Terminal feature.
I confirmed this today with a 2005 PCM here in my corral of parts.
OK, I've got a tech II (clone) so i can do this.
Next question: Should I clear it and drive around with no trailer for a week before my trip so it learns daily driver conditions or should I clear it with the trailer hooked up on the day I leave and let it learn with the heavy load.
Or can I do both and clear it whenever I change the conditions?
Next question: Should I clear it and drive around with no trailer for a week before my trip so it learns daily driver conditions or should I clear it with the trailer hooked up on the day I leave and let it learn with the heavy load.
Or can I do both and clear it whenever I change the conditions?
Well before clearing it I would be certain to read and save the current values for all the cells. Maybe take pictures of the Tech 2 screen(s) with all the TAP Cell data for 1-2 adapt and 2-3 adapt screens. There will be 4 screens of data total. There may be good diagnostic data in there. You might also find the values in there may be practically nil anyway, though I suspect this is unlikely.
I would be cautious about repeatedly clearing data that suggests significant corrections are in force. In other words I would evaluate what I saw before randomly clearing this learned data.
Yes, definitely good to save the data.
If you were doing this would you 'learn' with or without the trailer?
If you were doing this would you 'learn' with or without the trailer?
I sort of wonder if it matters. The learned adjustments are saved in different cells based on things like engine load, torque and so on. Cell 4 is the lowest torque load and the highest cell number would be for the highest torque loads. So it seems like the cells adjusted would be different with the trailer load vs without?
Sort of like if I learn with the trailer it'll adjust and fill the top half of the map with new data and when I run with no trailer it'll adjust and fill the lower half?
I guess I'll just record what's there and blank it out tomorrow.
I guess I'll just record what's there and blank it out tomorrow.
I have read a few descriptions of how the system should work and it leads me to believe that these values don't change rapidly. For one thing, it is said that for each shift the system evaluates whether or not that particular shift is a valid one to judge with. Like if the trans temperature is not up to a threshold value then that shift is not used. And if maybe the AC compressor kicked in during the shift then that shift data is tossed out. Things that may affect engine rpm that are not transmission shift related can get a shift tossed out of the running.
Reading about the temperature threshold makes me wonder what that threshold is? And if we add auxiliary coolers might we end up with a temperature that's too low and the adapt system then rarely actually gets a shift it feels is valid for consideration? Who knows!
Seems like long term monitoring of the values is about the only way to see if the system is actually doing its job.
I am going to tack this question here since it is somewhat related.
Does anyone know for certain what year the transmission adaptive feature began on our GMT360/370 platform?
When I use my Tech 2 and select model year 2002 there is no menu selection for reading or resetting the TAP values. If I select the 2003 model year then there are selections for reading and clearing these values. However, looking at my 2002 (built in 2001) TrailBlazer all locations where TAP values would be are zero. Seems unlikely for a trans that was rebuilt in 2014 and approaching 70000 miles ago.
Is it possible the 2002 model years did not have the adaptive feature?
My 2005 Yukon was rebuilt 3 years ago and shows maybe a dozen cells where the pressures are backed off varying amounts from the standard model. I have another scan of this data from 2 years ago and can see the same cell pressures were backed off a little further back then so there is evidence one would expect to see as the trans wears.
Does anyone know for certain what year the transmission adaptive feature began on our GMT360/370 platform?
When I use my Tech 2 and select model year 2002 there is no menu selection for reading or resetting the TAP values. If I select the 2003 model year then there are selections for reading and clearing these values. However, looking at my 2002 (built in 2001) TrailBlazer all locations where TAP values would be are zero. Seems unlikely for a trans that was rebuilt in 2014 and approaching 70000 miles ago.
Is it possible the 2002 model years did not have the adaptive feature?
My 2005 Yukon was rebuilt 3 years ago and shows maybe a dozen cells where the pressures are backed off varying amounts from the standard model. I have another scan of this data from 2 years ago and can see the same cell pressures were backed off a little further back then so there is evidence one would expect to see as the trans wears.
I took pictures of all the TAP pressures and then reset them all to 0.
I've got a week to drive around and let it learn before I hook the trailer up for our vacation trip.
I'll pull the TAP pressures at the end of the week to see which ones have been adjusted with no load from the trailer and then I'll pull them again at the end of the trip.
Any other data I should collect?
TJ - anything I can do here that would give you data that would be useful?
I've got a week to drive around and let it learn before I hook the trailer up for our vacation trip.
I'll pull the TAP pressures at the end of the week to see which ones have been adjusted with no load from the trailer and then I'll pull them again at the end of the trip.
Any other data I should collect?
TJ - anything I can do here that would give you data that would be useful?
You have any interest in trying to use Torque Pro to see your TAP pressure values? And what TAP Cell is current? As you have seen with the Tech 2 there are a lot of pressure cells there. So it would take a bunch of screen room in Torque Pro.
As it turns out I believe I just worked out how to read these TAP pressure cell values. The behind the scenes details are thus: The Tech 2 reads these values from "data blocks" that are read with service $3C. We can also read them with Torque Pro. There are usually like 6 bytes in each data block though I have seen some with less.
I can whip up a file for import to Torque Pro in much the same way we import the "[GM]" PIDs there.
That would still leave having to place all those 'pids' onto Torque Pro dashboards, a tedious process for sure.
For curiosity sake, what sort of values did you see? Did any stand out as being considerably higher or lower than the rest?
After the reset,,,, did you display ALL the cells and confirm they were at zero?? Did you have values specifically in cells 12 through 16 for either of the 1-2 or 2-3 adapts??
I ask this because I just explored this clearing of TAP with my Tech 2 and a 2005 PCM. From the Tech 2 screen there were no error messages in the clearing operation. However TAP cells 12 through 16 in both 1-2 and 2-3 adapts were NOT cleared. In my data log I can see the error. And if I displayed cells 12 through 16 the previous values were unchanged.
I tried using different year selections and all of the 2003 to 2005 years show the very same error and fail to clear cells 12 through 16.
Using 2006 did successfully clear the values even though 2006 uses a different PCM. The TAP clear Tech 2 function for 2006 uses a different method than the 2003 through 2005 years.
I suggest having a look at your TAP cells 12 through 16 in both the 1-2 adapts and 2-3 adapts.
Fist of all, I don't see TAP cells 15 and 16, I also don't see cell 9 on the 2-3 screen
I checked after clearing them and I had all zeros after the reset.
My TechII is a knockoff
50 kPa = 7.25psi.
A lot of the 1-2 numbers didn't change very much, a few are a bit lower and a few are a bit higher. Cell 4 dropped from 53 to 4, 9 from 74 to 41 and 10 from 41 to 10. 6/7/8 all went up slightly. This is the shift where the band is engaged by the servo, maybe I need new springs in there? Maybe the new band hasn't bedded in yet?
The 2-3 numbers are sure a lot lower. I wonder if doing the Sonnax ream and sleeve of the PWM valve raised the pressure so that the TAP doesn't now have to turn it up to get a decent shift into third.
I now wish I could get a set of TAP data from a new 4l60e to see if my 1-2 numbers are a concern.
I checked after clearing them and I had all zeros after the reset.
My TechII is a knockoff
50 kPa = 7.25psi.
A lot of the 1-2 numbers didn't change very much, a few are a bit lower and a few are a bit higher. Cell 4 dropped from 53 to 4, 9 from 74 to 41 and 10 from 41 to 10. 6/7/8 all went up slightly. This is the shift where the band is engaged by the servo, maybe I need new springs in there? Maybe the new band hasn't bedded in yet?
The 2-3 numbers are sure a lot lower. I wonder if doing the Sonnax ream and sleeve of the PWM valve raised the pressure so that the TAP doesn't now have to turn it up to get a decent shift into third.
I now wish I could get a set of TAP data from a new 4l60e to see if my 1-2 numbers are a concern.
I need to sleep on this.
I explored a little more about the absent 2-3 TAP Cell 9 and found my Tech 2 (clone) also has this missing. I experimented with using other year selections and they also showed no 2-3 #9. But here it got really weird. I know the memory blocks where the TAP values are read by the Tech 2 and in the 2006 PCM I have there is a value for 2-3 TAP #9!! But the Tech 2 does not display it!! Why would a PCM update a TAP cell if it were not used?? Is it a possible bug in the Tech 2 not displaying this cell?
I'm just trying to interpret the numbers to see if they point to anything.
Having shift 1-2 still require extra pressure to get to it's optimum time, I think, tells me the servo isn't fast enough applying the band to get into second or the band is slipping?
I've purchased the OTC kit to monitor the pressure from the side port so this weekend I'll be doing the test with the Tech-II and the pressure gauge to see if the pressure responds correctly to the adjustments.
I'll also drain the fluid and drop the pan and look for any metal that may indicate I missed something.
If all is good I'll change the u-joints and take off on holiday.
Having shift 1-2 still require extra pressure to get to it's optimum time, I think, tells me the servo isn't fast enough applying the band to get into second or the band is slipping?
I've purchased the OTC kit to monitor the pressure from the side port so this weekend I'll be doing the test with the Tech-II and the pressure gauge to see if the pressure responds correctly to the adjustments.
I'll also drain the fluid and drop the pan and look for any metal that may indicate I missed something.
If all is good I'll change the u-joints and take off on holiday.
I hooked up the 400PSI OTC pressure gauge to the service port today, it's a PIA. I had to drop the front propeller shaft and remove the cable and the electronic switchbox on the shaft to get to it. The hose barely fit but I got it in.
With the Tech II I was able to change the PWM signal to the EPC solenoid and read the resulting line pressure and sure enough all readings were in spec. At idle I was able to vary the line pressure from 62psi to 180psi in ten increments.
I'm happy with that, I think this trans is good to go.
With the Tech II I was able to change the PWM signal to the EPC solenoid and read the resulting line pressure and sure enough all readings were in spec. At idle I was able to vary the line pressure from 62psi to 180psi in ten increments.
I'm happy with that, I think this trans is good to go.
Climbed through all the Rocky mountain passes without any problems!
We went through some small passes the first day then through Rogers Pass the second and then Kicking Horse Pass and Bow Pass the third. (5000-6000feet)
The trans shifted from 3-2-1 as we climbed with the periods in 1rst being brief spurts near the top of some long climbs. I don't think we slowed below 50km/30mph even on the steepest slopes. The engine temp stayed at 100C/212F even in first at 5000RPM so while it felt like we were screaming and about to explode we really weren't, we were not even close to max rpm and the engine temp was perfect. We spend most of the long climbs in 2nd at about 3500rpm.
I've also learned that when you tow in 3rd the overrun clutch is engaged in every gear so the downhill slopes were easy to do with minimal braking required.
I couldn't be happier with the result.
We're now out on the prairie heading north so it's easy going for a week or so before we need to cross back through mountains to get home.
We went through some small passes the first day then through Rogers Pass the second and then Kicking Horse Pass and Bow Pass the third. (5000-6000feet)
The trans shifted from 3-2-1 as we climbed with the periods in 1rst being brief spurts near the top of some long climbs. I don't think we slowed below 50km/30mph even on the steepest slopes. The engine temp stayed at 100C/212F even in first at 5000RPM so while it felt like we were screaming and about to explode we really weren't, we were not even close to max rpm and the engine temp was perfect. We spend most of the long climbs in 2nd at about 3500rpm.
I've also learned that when you tow in 3rd the overrun clutch is engaged in every gear so the downhill slopes were easy to do with minimal braking required.
I couldn't be happier with the result.
We're now out on the prairie heading north so it's easy going for a week or so before we need to cross back through mountains to get home.
Mooseman
Moderator
Mooseman
Moderator
I usually use dials with a digital readout on the middle or straight up digital.
That's excellent temps especially while towing.
That's excellent temps especially while towing.
This is an area where the Car Scanner ELM OBD2 app shines. Enable data recording and then just select what you want to see when you start out, display it on a single combined graph and it will record all that you have selected and you can review the data later and keep your eyes on the road. The graphing is built right into the App.
I reconfigured one of the screens to have coolant temp and trans fluid temp as digital readouts with a large graph style box for the O2 sensor yesterday. This worked well as I can read it at a glance and the big graph is easy to see.
One mistake is that I thought my trans fluid was running around 60C but in fact it's about 80C/196F. I think that's still pretty good when towing 5000 lbs.
One mistake is that I thought my trans fluid was running around 60C but in fact it's about 80C/196F. I think that's still pretty good when towing 5000 lbs.
