4l60e no gear at wot?? Other issue too..
02-08-2012, 04:44 PM
#1
4l60e no gear at wot?? Other issue too.. been having a constant issue where if i floor it , it acts like it looses the gear, BUT at 75 80% throttle its there.
Not a slipping feel either..just acts like it looses the gear or pressure.
Also most of the time will not go into any gear unless shifter is pulled down to eithr 1st or 2nd and then will upshift correctly after up to speed in 3rd and 4th!?!
I also noticed it takes off in 2nd gear unless i manually put it in 1st.
Trans has all aftermarket clutches pistons and servos and boost valve.
This is a 94 4l60 e with a vigilante 2600 stall with a 02 pcm running the show.
I would liketo hear any advice and likely causes. I dont even no where to start.
I have not rebuilt the valvebody and all sensors are stock 94 stuff so this is the only thing i can think of.
Not a slipping feel either..just acts like it looses the gear or pressure.
Also most of the time will not go into any gear unless shifter is pulled down to eithr 1st or 2nd and then will upshift correctly after up to speed in 3rd and 4th!?!
I also noticed it takes off in 2nd gear unless i manually put it in 1st.
Trans has all aftermarket clutches pistons and servos and boost valve.
This is a 94 4l60 e with a vigilante 2600 stall with a 02 pcm running the show.
I would liketo hear any advice and likely causes. I dont even no where to start.
I have not rebuilt the valvebody and all sensors are stock 94 stuff so this is the only thing i can think of.
02-08-2012, 07:59 PM
#2
The WOT issue could be related to low fluid. Not sure though....
The rest, can't say as I've heard of or experienced that set of symptoms before. I would recommend getting a scanner on it and see what the pressure manifold switch is reporting vs. the manual valve position.
Is this a new unit and hasn't been happy simce it was insatlled or one that was fine and now you have these symptoms?
g
The rest, can't say as I've heard of or experienced that set of symptoms before. I would recommend getting a scanner on it and see what the pressure manifold switch is reporting vs. the manual valve position.
Is this a new unit and hasn't been happy simce it was insatlled or one that was fine and now you have these symptoms?
g
02-08-2012, 11:10 PM
#4
If it's reporting the proper gear when it's selected and commanded as well then the issue is internal. Be sure to check the speed sensor operation diligently as well... code or no code.
It's not abnormal to have to add nearly a full quart to keep the filter saturated at WOT. Maybe not that much, but don't be afraid to go past the full mark on the stick. Just don't get carried away.
Has any trns DTC reporting been deleted? What software are you using to datalog and tune with?
There are actually quite a few possibilities that come to mind... most of which are all internal to the valve body or rotating assembly. But with proper details we'll solve it or at least get you on the right road....
Is this a new unit or one that has been on the road a while? Is this either of the vehicles in your sig? If it's the Chevelle, what controller are you using to manage it?
g
It's not abnormal to have to add nearly a full quart to keep the filter saturated at WOT. Maybe not that much, but don't be afraid to go past the full mark on the stick. Just don't get carried away.
Has any trns DTC reporting been deleted? What software are you using to datalog and tune with?
There are actually quite a few possibilities that come to mind... most of which are all internal to the valve body or rotating assembly. But with proper details we'll solve it or at least get you on the right road....
Is this a new unit or one that has been on the road a while? Is this either of the vehicles in your sig? If it's the Chevelle, what controller are you using to manage it?
g
02-09-2012, 06:17 AM
#5
Yes this is the 70 Chevelle in Sig. I rebuilt the 4l60e last year and shortly after threw a rod in the old setup(94 lt1/4l60e)..sat for 7 months before swapping in a 6.0 but still using the 94 4l60e.
The trans was good for the first week before running into the issue.
Im using hptuner 2bar SD setup on a 02 truck pcm. Line pressure was raised and shift pressures were modded for propper shifts and turned off the code(s) and adjusted the tables for the stall.
The trans was good for the first week before running into the issue.
Im using hptuner 2bar SD setup on a 02 truck pcm. Line pressure was raised and shift pressures were modded for propper shifts and turned off the code(s) and adjusted the tables for the stall.
02-09-2012, 09:55 AM
#6
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Take a look at a couple of things in the trans tune. Start
with the force motor table, rightmost column. If that has
a high value, while the neighbors are 90mA or some such,
then a very high commanded line% number will make the
PCS blow off all pressure.
People like to change the max line% limit field, which is
what prevents the factory setup from stepping in that
hole. But if you raise that, you would allow the rightmost
column to be indexed, meaning it wants zero or low
current values (full pressure) like the other high-load
columns.
Does your scanning show force motor current? That's
the real deal, as far as delivered line pressure goes
(since we don't have an actual pressure, go by the
PCS current to see line pressure intention).
with the force motor table, rightmost column. If that has
a high value, while the neighbors are 90mA or some such,
then a very high commanded line% number will make the
PCS blow off all pressure.
People like to change the max line% limit field, which is
what prevents the factory setup from stepping in that
hole. But if you raise that, you would allow the rightmost
column to be indexed, meaning it wants zero or low
current values (full pressure) like the other high-load
columns.
Does your scanning show force motor current? That's
the real deal, as far as delivered line pressure goes
(since we don't have an actual pressure, go by the
PCS current to see line pressure intention).
02-09-2012, 10:06 AM
#7
Ok, i believe i have the Force motor current config added onto my scanners table. I will have to take a look at it.
Now speaking of the Force motor current table, the last column doesnt match whats next to it..say the send to last column on the right is down to 200ish but the last column on both the neg and positive tables are at 1200ish. This almost matches the first and second column on the left.
Correct me if im wrong, but the lower the value the higher the pressure should be on these tables correct? I believe these are stock settings but may be wrong. I just figured they are set that way for computer adjustment.
The max limit line you speak of, is that the one that is set to 90 from the factory? I did max it to 96
Now speaking of the Force motor current table, the last column doesnt match whats next to it..say the send to last column on the right is down to 200ish but the last column on both the neg and positive tables are at 1200ish. This almost matches the first and second column on the left.
Correct me if im wrong, but the lower the value the higher the pressure should be on these tables correct? I believe these are stock settings but may be wrong. I just figured they are set that way for computer adjustment.
The max limit line you speak of, is that the one that is set to 90 from the factory? I did max it to 96
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02-09-2012, 05:12 PM
#8
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This is what I'm talking about. At 96% commanded line pressure
you are into full blowoff and get none instead. The only thing
preventing this is the max line% value (been a while, I recall 95%
but might have lost a brain cell or two since).
I'd tamp that force motor column value down, just copy its
neighbor and see what comes of it. Now full power applied
across a min-line-pressure clutch may not have had a happy
outcome, but maybe you didn't varnish it up totally if you
quit the first time it happened.
you are into full blowoff and get none instead. The only thing
preventing this is the max line% value (been a while, I recall 95%
but might have lost a brain cell or two since).
I'd tamp that force motor column value down, just copy its
neighbor and see what comes of it. Now full power applied
across a min-line-pressure clutch may not have had a happy
outcome, but maybe you didn't varnish it up totally if you
quit the first time it happened.
02-09-2012, 08:24 PM
#9
That's very good information Jimmy! I believe you are on to something there regarding the EPC tables.
Like he said, if you didn't stay at WOT too long or too many times when it did not upshift then you just may get lucky. It might be wise to drop the pan and change the fluid and filter if the tune mods help it out.
g
Like he said, if you didn't stay at WOT too long or too many times when it did not upshift then you just may get lucky. It might be wise to drop the pan and change the fluid and filter if the tune mods help it out.
g
02-14-2012, 06:59 AM
#10
Hey guys i had no change in this issue at wot after changing that last column in that table.
Is it possible there is a seal blowing out at high pressure but sealing at lower pressure?
Im on the lookout for a good used valvebody or a cheap reman vb to replace the high mileage one thats in there. Has around 2k miles on it, with the exception of the billet forward piston.
What internal to you guys think this could be?
Is it possible there is a seal blowing out at high pressure but sealing at lower pressure?
Im on the lookout for a good used valvebody or a cheap reman vb to replace the high mileage one thats in there. Has around 2k miles on it, with the exception of the billet forward piston.
What internal to you guys think this could be?
02-15-2012, 10:37 AM
#13
On a side not..every once in a while, especially after it has sat over night, when shifting to 2nd it binds very bad and slows the car down till i downshift back to 1st then right back to 2nd and its fine.. something has to be going on with my valving or something.
02-15-2012, 07:29 PM
#14
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I have similar problems & talked to my crew chief (actually my supervisor at work) he told me to drop the pan and let it drain overnight, He will be over to change shift selinoids. I dont know I'm taking his word but he Was a GM mechanic for many years and specializes in trannys. If I find out before you I let you know. Mine started missing the 1/2 shift hit the rev limiter then shift, then it wouldn't down shift to first when I came to a stop unless i manually did it, Then one day I did a hole shot the RPM's went to 6000 I wasn't spinning but I was'nt going anywhere. i THOUGHT THE CONVERTER MAY BE SHOT ,OR Clutches,band ....if its not the selinoids he said we will drop it and rebuild it.
02-28-2012, 04:27 AM
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Might I suggest pulling this trans out of the vehicle and bringing it to Gil at Ace to have him go through it. It seems that something is being missed in the build here and I'm pretty confident that he will get you straightened out!
02-28-2012, 06:36 AM
#18
Ive been also having issues with the converter not locking up and thought it might had been the selenoid and changed it llast night but did not help.
P0740 code was thrown and came across a post about it being the pcm in one case...jeez i hope this is not the case..between hptuner 2bar credits and a cost of another pcm..
P0740 code was thrown and came across a post about it being the pcm in one case...jeez i hope this is not the case..between hptuner 2bar credits and a cost of another pcm..
