How to Reset Transmission Control Module?

[ShookieJay]

Hey guys, sorry for the dumb question, but I've searched the forum several times as well as Google and haven't found an answer.

Can anyone tell me how to reset the TCM, hopefully without a scan tool? I just installed a shift kit and corvette servo, as well as replaced the shift accumulators in the 4L60E on my 03 Tahoe. The instructions that came with the shift kit say you should reset the TCM so it can re-learn shift points, but I have no clue how to do that...

 

[89Suburban]

@NickTransmissions

 

[Doubeleive]

You need a tool like a tech2

 

[NickTransmissions]

Hey guys, sorry for the dumb question, but I've searched the forum several times as well as Google and haven't found an answer.

Can anyone tell me how to reset the TCM, hopefully without a scan tool? I just installed a shift kit and corvette servo, as well as replaced the shift accumulators in the 4L60E on my 03 Tahoe. The instructions that came with the shift kit say you should reset the TCM so it can re-learn shift points, but I have no clue how to do that...

Not a dumb question....What shift kit is this?

I've installed thousands of them into 4L60Es over the years and never had to do a relearn. The 4L60Es and 80Es don't need it; the adaptive relearn requirement after trans service didn't arrive until the 6L transmissions where the TCM (TEHCM) is part of the transmission assembly and not integrated into the PCM or otherwise off-board of the transmission.

What was your servo travel once you installed the corvette servo? Should have been something in the neighborhood of .050-.090...Did you use Sonnax pinless accumulators for the forward, 1-2 and 3-4 or just the springs that came in the shift kit? Did you replace the 3-4 accumulator piston with a new one (that should always be done as those wear aggressively at the piston pin bore)?

 

[Scottydoggs]

unhook the battery for 30 minutes. your tcm is not stand alone module. its in the pcm, so taking power from it resets everything and it all relearns.

 

[Mudsport96]

unhook the battery for 30 minutes. your tcm is not stand alone module. its in the pcm, so taking power from it resets everything and it all relearns.

It would work, but really don't even "need" to do that. Couple days of driving and it will work itself out.

Not a dumb question....What shift kit is this?

I've installed thousands of them into 4L60Es over the years and never had to do a relearn.

Ditto, what kit.
And not thousands, but enough to know a relearn isn't necessary.

 

[Mudsport96]

Hey guys, sorry for the dumb question, but I've searched the forum several times as well as Google and haven't found an answer.

Can anyone tell me how to reset the TCM, hopefully without a scan tool? I just installed a shift kit and corvette servo, as well as replaced the shift accumulators in the 4L60E on my 03 Tahoe. The instructions that came with the shift kit say you should reset the TCM so it can re-learn shift points, but I have no clue how to do that...

So did you find anything damaged when it was disassembled? I remember that you had a thread about bad shifting a couple months ago. I am guessing that is why you went with the parts you installed.

 

[ShookieJay]

Not a dumb question....What shift kit is this?

I've installed thousands of them into 4L60Es over the years and never had to do a relearn. The 4L60Es and 80Es don't need it; the adaptive relearn requirement after trans service didn't arrive until the 6L transmissions where the TCM (TEHCM) is part of the transmission assembly and not integrated into the PCM or otherwise off-board of the transmission.

What was your servo travel once you installed the corvette servo? Should have been something in the neighborhood of .050-.090...Did you use Sonnax pinless accumulators for the forward, 1-2 and 3-4 or just the springs that came in the shift kit? Did you replace the 3-4 accumulator piston with a new one (that should always be done as those wear aggressively at the piston pin bore)?

Ngl, I have no clue about the travel lol I just put it in the same way the other one was. Now that you mention it tho, that sounds important. Where do I measure this travel? And as for the accumulators, yes I used Sonnax.

It would work, but really don't even "need" to do that. Couple days of driving and it will work itself out.


Ditto, what kit.
And not thousands, but enough to know a relearn isn't necessary.

Ok, ill disconnect the battery just for hahas. I have no complaints with the way it's shifting now, but I wanted to be on the safe side. And I went with the basic kit from transgo. I don't need anything crazy, just wanted to address the sloppy 1-2 shift.

So did you find anything damaged when it was disassembled? I remember that you had a thread about bad shifting a couple months ago. I am guessing that is why you went with the parts you installed.

Wow good memory. Only damage I found was a broken spring in the 1-2 accumulator. Everything else looked good. Fluid was very clean as well, granted, I changed the fluid/filter a little over a year ago. I'm kicking myself for not doing this sooner lol the shifts are prompt and firm. I have peace of mind now not worrying about burning the clutch on the 1-2.

Thanks everyone for the answers, I appreciate y'all

 

[Mudsport96]

Was it the transgo kit?

 

[NickTransmissions]

Ngl, I have no clue about the travel lol I just put it in the same way the other one was. Now that you mention it tho, that sounds important. Where do I measure this travel? And as for the accumulators, yes I used Sonnax.

Ok, ill disconnect the battery just for hahas. I have no complaints with the way it's shifting now, but I wanted to be on the safe side. And I went with the basic kit from transgo. I don't need anything crazy, just wanted to address the sloppy 1-2 shift.

Wow good memory. Only damage I found was a broken spring in the 1-2 accumulator. Everything else looked good. Fluid was very clean as well, granted, I changed the fluid/filter a little over a year ago. I'm kicking myself for not doing this sooner lol the shifts are prompt and firm. I have peace of mind now not worrying about burning the clutch on the 1-2.

Thanks everyone for the answers, I appreciate y'all

Measure it at the servo cover. At this point all you need to do is take the head shield off and press in on the cover until the travel stops and see how far it travels. For reference take a pair of dial calipers and set them open .050 and compare that distance to your servo travel and see if they're similar.

Was it the transgo kit?

Yep, he used the SK4L60E and no where in the instructions does it call for any tcm resets.

 

[Mudsport96]

Measure it at the servo cover. At this point all you need to do is take the head shield off and press in on the cover until the travel stops and see how far it travels. For reference take a pair of dial calipers and set them open .050 and compare that distance to your servo travel and see if they're similar.


Yep, he used the SK4L60E and no where in the instructions does it call for any tcm resets.

Yeah I see that now. Not sure how missed it... oh may have been the "eggnog".
Yeah even the HD2 kit doesn't say anything about resetting the shift tables( on the vehicles ive done), so I can't see why the base kit would.

 

[ShookieJay]

Measure it at the servo cover. At this point all you need to do is take the head shield off and press in on the cover until the travel stops and see how far it travels. For reference take a pair of dial calipers and set them open .050 and compare that distance to your servo travel and see if they're similar.


Yep, he used the SK4L60E and no where in the instructions does it call for any tcm resets.

OK thanks, I'll check that this weekend. The servo kit came with 2 shims and I installed 1. I kinda breezed thru the servo install because it was a long day doing the shift kit and I was burned out lol

Yeah I see that now. Not sure how missed it... oh may have been the "eggnog".
Yeah even the HD2 kit doesn't say anything about resetting the shift tables( on the vehicles ive done), so I can't see why the base kit would.

You both are right, after reading through the instructions, the kit does not say to do that. I had watched a video on installing the shift kit and the guy had said to do it. (though he didn't say how to do it) He said especially if you had the bump on the 1-2 because it would have learned to try and compensate for it. I didn't read the entire instructions, mostly followed the video and referenced the instructions for the valve body stuff (that part made me nervous, having never gotten into one before). I ended up leaving the battery disconnected last night, figured it couldn't hurt.

 

[Mudsport96]

Did you set it up for a firm shift?

 

[ShookieJay]

Did you set it up for a firm shift?

Yes, I drilled the 1-2 hole to .070

 

[rockola1971]

Wow good memory. Only damage I found was a broken spring in the 1-2 accumulator. Everything else looked good. Fluid was very clean as well, granted, I changed the fluid/filter a little over a year ago. I'm kicking myself for not doing this sooner lol the shifts are prompt and firm. I have peace of mind now not worrying about burning the clutch on the 1-2.

Thanks everyone for the answers, I appreciate y'all

Why would you have to be concerned about "burning the clutch on the 1-2"? The 1-2 accumulator spring is there to cause the shift not to be neck jerking. A broken 1-2 accumulator spring will cause the 1-2 shift to be firmer and quick which causes the exact opposite of being able to burn the 1-2 clutches. Less time for the shift to happen, less time for the clutches to get hot during slippage, especially if the throttle is mashed.
A broken 1-2 accumulator spring will NOT damage your transmission. It is quite common to find a broken 1-2 spring on a 700r4/4l60/4l60e when they are opened up for the first time ever with high miles. Its pretty much expected and has to be replaced whether its broken or not.

 

[ShookieJay]

Why would you have to be concerned about "burning the clutch on the 1-2"? The 1-2 accumulator spring is there to cause the shift not to be neck jerking. A broken 1-2 accumulator spring will cause the 1-2 shift to be firmer and quick which causes the exact opposite of being able to burn the 1-2 clutches. Less time for the shift to happen, less time for the clutches to get hot during slippage, especially if the throttle is mashed.
A broken 1-2 accumulator spring will NOT damage your transmission. It is quite common to find a broken 1-2 spring on a 700r4/4l60/4l60e when they are opened up for the first time ever with high miles. Its pretty much expected and has to be replaced whether its broken or not.

Hmmm... Well maybe it had nothing to do with the broken spring, but prior to doing this, the 1-2 was pretty bad. It would shift, then a second later it would jerk, almost as if it had just fully grabbed. I'm no expert, but to me it seemed like the engagement was pretty delayed.

 

[rockola1971]

Hmmm... Well maybe it had nothing to do with the broken spring, but prior to doing this, the 1-2 was pretty bad. It would shift, then a second later it would jerk, almost as if it had just fully grabbed. I'm no expert, but to me it seemed like the engagement was pretty delayed.

It is possible that the spring got all wedged up in the bore and cause that. Usually the symptom is just neck jerking 1-2 shifts which most people dont like but its awesome for a race car.

 

[ShookieJay]

It is possible that the spring got all wedged up in the bore and cause that. Usually the symptom is just neck jerking 1-2 shifts which most people dont like but its awesome for a race car.

It's funny you say that, because before, if I had it in tow/haul, it would BANG into 2nd, neck jerking as you say. But in regular drive it would be sloppy. The shifts now are firm and quick in a good way, but not as jarring as before if it was in tow/haul

 

[rockola1971]

It's funny you say that, because before, if I had it in tow/haul, it would BANG into 2nd, neck jerking as you say. But in regular drive it would be sloppy. The shifts now are firm and quick in a good way, but not as jarring as before if it was in tow/haul

Tow/Haul mode causes quicker firmer shifts. The last thing you want is to be giving moderate throttle and the shift to be loose and sloppy while towing. That causes extra heat, clutch wear and will burn up the 2-4 band during 1-2 and 3-4 shifts.
It really sounds like your 1-2 spring had the piston all wedged up in the bore. Do you remember pulling the 2 spring pieces? Did they come right out or were they all tangled up together?

 

[ShookieJay]

Tow/Haul mode causes quicker firmer shifts. The last thing you want is to be giving moderate throttle and the shift to be loose and sloppy while towing. That causes extra heat, clutch wear and will burn up the 2-4 band during 1-2 and 3-4 shifts.
It really sounds like your 1-2 spring had the piston all wedged up in the bore. Do you remember pulling the 2 spring pieces? Did they come right out or were they all tangled up together?

About a third of it broke off. It a came right out but the broken-off bit was tangled into the remaining spring. Miraculously, there wasn't any significant scoring on the cylinder wall