First thing is get rid of that adapter and just try the memcal alone, Those are a HUGE failure point regardless of brand. Report back ;)Originally Posted by boba
First thing is get rid of that adapter and just try the memcal alone, Those are a HUGE failure point regardless of brand. Report back ;)
-Carl
I found and ordered a replacement DRAC, my testing approach today to start with will be to put my scope on both trans output speed and VSS input to see what I get.
Question on ditching the adapter though, you say the BAMM is for a 3.73 gear, so if I remove the adapter it will control the trans, I'll just be getting a different speed input?
I changed back to the original AWUM memcal, still had a MIL & low idle, re-seated the chip but didn't bottom it out in the receiver and it was suddenly all good.
I don't know what to think of this now, except it's going to be hard for me to trust it. I'd do more if I had a work environment where I could, but that isn't the case for me right now.
I should get the DRAC in a few days, I have no idea now if that will change anything.
Wasn't able to get any scope patterns out of the current DRAC today, but that might be my fault - I need some more working time with the scope I have.
Hiya,
I'm not sure if you have internet on your vacation. How's everything going?
-Carl
I'm full time in this thing In-Tech, it sucks to have my house break down on me, but I'm doing the snowbird thing so at least I'm in good weather.
Yes I do have internet (most of the time) I've had to learn to adapt on that like everyone else who does this. It's workable.
Updates since I've posted last - the DRAC module I ordered was a kerfuffle, seller sent the wrong part so I couldn't compare it to the one I had. He does have the correct unit and he's a good guy so if do end up needing the part I'll know where to get it.
I've also had a chance to open up the rest of the wiring harness and can say it's been thoroughly checked out and I haven't found any damage, some discrepancies compared to the schematics but I'm sure that's due to manufacturing changes that GM made during production, and it has been working fine up 'till it didn't.
Long & short is that I'll be putting it in a trans shop ASAP and getting the 4L80 rebuilt.
It's still going into limp mode, even though it's running better - and I don't want to drive 1200 miles back to home base in 2nd gear.
What really bugs me about the whole thing is that when It throws the MIL and goes into limp mode I get a no com with the ECU, can't read a darn thing, no codes or data all.
That and it doesn't store any codes either. This is consistent with both PCM's that I've had in it over the last six weeks and I have no idea why.
I get an MIL and the PCM totally sh*t's the bed. It's frustrating at levels I probably shouldn't try to describe, but you get the picture.
Other symptoms that lead me to suspect the trans are my speedometer needle is now pulsing at low speeds. I don't remember that from any time in the previous five years I've owned this thing.
In looking through some 4L80E rebuild videos I've seen rebuilders point out weak sprag clutches and torque converters along with everything else a manufacturer does to make their stuff just good enough to get through warranty, so my best guess is a failed rear sprag and a cracked drum that may have deformed the output tone ring.
This rig weighs in at a lithe 6 tons and it's got 125k miles so I'm probably due anyway.
I'll put that all on red and take it with me to the transmission shop casino.
'Cause baby needs a new pair of shoes!
Hiya boba,
The next thing I would do is a replacement internal harness for the 4L80E(another notorious fail). You're going to want one for the rebuild anyway(as well as all solenoids during rebuild), so, money well spent. Easily can be causing all your trans and comm issues.
-Carl
I have one, I ordered it when I replaced all the trans solenoids early on, I didn't know it needed an external adapter piece because of the connector style change and the parts supplier didn't tell me, so the old harness is still in there.
I dropped the pan once out here in the dessert, I don't want to do that again - I'll let a shop look at it & if it's just a harness I'll be grateful.
Well I'm ready to be done with this adventure.
I've poured all the blood sweat tears and resources into this POS that I care to. It's still f*cked and there doesn't seem to be any way the un-f*ck it.
I got my transmission external wiring harness adapter (for $117) yesterday and very carefully went over every wire before I installed it.
Dropped the pan and replaced the internal harness and got all of that squared away.
There is no damage to the original harness that I can find, and the result is the same, MIL and limp mode.
I'm so mad I can barely type this out.
The tech info I've been able to get is horrid and the build quality is worse.
At this point I either put a haltech on this thing or burn it, but GM can kiss my ass.
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