4L80E lockup issue when towing
07-15-2018, 08:52 AM
#1
4L80E lockup issue when towing
I did a 4L80E swap on my 08 avalanche 5.3, ported 862, 208/212 cam, headers. I have a used Circle D 3000-3200 economy converter in it. Trans is a 5 pinion from an 05 Express. Everything is fine without a load, I adjusted the shift points to match the converter, took out the TM, and increased the lockup speed so it’s not dragging on lockup. The base trans tune is an 08 express from the HPT repository.
The issue lies when I’m towing something heavier than 2000lb or so. It will be ok for the first 20min of loxked up highway driving at 70mph but then maybe when accelerating, it will unlock and never lockup again. Then it throws the “transmission component slipping” code. Can’t rememebr what it is. Is my lockup clutch toast or am I asking too much of this smaller torque converter?
Thanks
Dan
The issue lies when I’m towing something heavier than 2000lb or so. It will be ok for the first 20min of loxked up highway driving at 70mph but then maybe when accelerating, it will unlock and never lockup again. Then it throws the “transmission component slipping” code. Can’t rememebr what it is. Is my lockup clutch toast or am I asking too much of this smaller torque converter?
Thanks
Dan
07-15-2018, 01:14 PM
#2
I did a 4L80E swap on my 08 avalanche 5.3, ported 862, 208/212 cam, headers. I have a used Circle D 3000-3200 economy converter in it. Trans is a 5 pinion from an 05 Express. Everything is fine without a load, I adjusted the shift points to match the converter, took out the TM, and increased the lockup speed so it’s not dragging on lockup. The base trans tune is an 08 express from the HPT repository.
The issue lies when I’m towing something heavier than 2000lb or so. It will be ok for the first 20min of loxked up highway driving at 70mph but then maybe when accelerating, it will unlock and never lockup again. Then it throws the “transmission component slipping” code. Can’t rememebr what it is. Is my lockup clutch toast or am I asking too much of this smaller torque converter?
Thanks
Dan
The issue lies when I’m towing something heavier than 2000lb or so. It will be ok for the first 20min of loxked up highway driving at 70mph but then maybe when accelerating, it will unlock and never lockup again. Then it throws the “transmission component slipping” code. Can’t rememebr what it is. Is my lockup clutch toast or am I asking too much of this smaller torque converter?
Thanks
Dan
It could be anything from the TCC valve installed incorrectly, the oring on the input shaft is mugged up or a converter issue.
I would not think it's a converter issue.
07-15-2018, 01:56 PM
#3
Ok. So under load even without a trailer it breaks loose on the interstate. But then I go get gas, about 15 minutes off the road, and now it’s fine again. Does this clear anything up? Ha. Trans was at 187* unlocked and 160* locked at 85mph. I have a 40k post radiator cooler.
08-03-2018, 12:35 PM
#4
My neighbor is a GM trans tech. His thoughts are when it unlocks under load, it immediately throws a code because the deviation from stock stall is so great and doesn't lock back up. Swapping for a K1 or B82 converter this weekend. Will post results.
09-12-2018, 10:13 AM
#6
Ok. So took it to a trans shop because after swapping converters, lost reverse. Or at least it engages but if I hit the gas it’s like it’s dragging. With the stock high stall K1 converter, it still does it. Trans shop told me low pressure issue 75 at idle 150 in reverse I think. So the band may not be engaging because the low pressure.
Trending Topics
09-12-2018, 03:54 PM
#8
I suppose. Dropped the VB and a bolt I’m pretty damned sure I didn’t touch (I would’ve removed it all the way) was loose near the reverse servo for some reason. I ordered new gaskets and gonna stick it back together. Took it apart to check the reverse servo. I’ll check back tomorrow evening and see what happens.
Thread
Thread Starter
Forum
Replies
Last Post
jmgak47
GM Drivetrain & Suspension
7
01-25-2014 01:57 PM
