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2006 4L80E Issue

JoeP1450

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Messages
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Location
Winchester KY
Sorry if I'm duplicating another thread,,, but I'm not seeing an issue similar to mine.

I have 2006 SILVERADO 6.0 gas, 4L80, 207,000 miles, 2nd owner. The truck shifts exactly as it should when start up cold. However,,, once truck gets up to operating temperature, it shifts "BANG" extremely hard!! All gears. Just like an old Turbo 350/400 with vacuum line off the modulator.

If I let off gas when it's time for shift (to let it shift soft/normal) it shifts even harder. If I am gassin on it kind of hard when shifting, it "seems" softer,,,, but of course it's still shifting hard.

Fluid level is good, fluid appearance is good, no burnt smell, I've drove truck about 30,000 miles and have not serviced trans. The only mod to the truck is SUPERCHIPS FlashPaq,,,, that is in 93 octane (I think that's what it's called) tune. I've put about 3500-4000 miles on it with the tuner on it.
 
Tuners like harsh shifts so you can "Feel the power" and not cook the trans by slipping so much with butter soft clutch burning shifts. Remove the tuner and see if the shifts are still hard. Check for codes as anything out can trigger a limp mode that shifts hard.
 
Thanks for your response Warwagon! I took the program out and returned to "stock tune" Ill find out in the morning what happens. My ignorance tells me, the tuner may not be the problem. I've ran the tuner 3500-4000 miles (quite possibly more) before I started having the issue.

Now,,, this doesn't mean the tuner didn't create the problem, because maybe it did. Again, my ignorance tells me, the slamming and banging when shifting with the programmer has caused damage with an already high mileage transmission. I was hesitant to run a programmer on a truck with high mileage to begin with.

Even before I put programmer on, a few times the tranny seemed to be a little flaky. Occasionally, after coming to a stop at a red light, it would seem to be taking off in a higher gear. But,, it did it so few times, I really ignored it,,, I guess I really didn't want to acknowledge the possible issue.

This truck is my daily driver that carries my air cooled MILLER welder, oxy/acc tanks, grinders, tools/etc and occasional tandem trailer hauling whatever.
 
Sorry Joe, I think the transmission is on it's way to a rebuild. A little bump in power from your tune just sped up the process a little. As Eddie Murphy would say "Time to show the tranny a little love and money."
 
Pull codes 1st and see if theres a slippage code. In case of slippage, the pcm reverts to max line pressure(banging shifts). Next up is check your maf sensor. Get some maf cleaner and clean it. Newer trucks base shifting off the maf sensor primarily, and many hard shifts are a dirty maf. Next step is get a pressure gauge on the trans. One thing that occurs espescially on high milage trucks that don't get serviced like they should is clutch material can build up in the pressure control solenoid. If the electrical side is working, the pcm won't code as theres no pressure sensor in the trans. If the pcs sticks, it can go to max pressure with no codes. The only way you'll find it is with a trans pressure guage hooked up. Your trans very well could be fine with the exception of a $30 PCS as I've seen many 4l80e's run 300K+ miles, a good example is my uncles 05 has over 400K on it, and is still going. They really are a good trans if you take care of them.
 
Thanks gentleman for your input!

As I stated last, I removed the programmer and returned back to "stock" tune. Drove truck this morning and as usual, shifts just as it should when cold. By time I get to town (11 miles) of course truck is up to operating temperature and all through town, at stop lights, stop signs, etc,,,, it shifts HARD,, BANG,,, WHAMM!!! Just as I figured, removing the programmer made no difference.

Drove to my buddies shop who has a scanner and had him scan codes. P0894 was the only code given.

Now again,, remember,,, I compared my 4L80E problems to a TURBO 350 or 400 trans problem,,,, so maybe this tells you how "out of date" I am. I used to work that era of vehicles and was NEVER transmission knowledgable!! So,,, give me a code,, add GOOGLE,,,, and I still know nothing.

I have read a little on this code, my ignorance tells me, it may be possible, to spend $125 on a master solenoid kit, change fluid and filter (which I certainly would do myself),,,, and this "MAY" or may not fix this issue. Certainly appreciate any ideas on this problem!

Call me "cheap" call me "poor" call me whatever you want,,, I'm in first year self employed, one man operation and not in position to drop $1000-$2000 into a trans repair/rebuild. However, I do have appointment next Tues to have local, reputable trans shop to drive it, scan it, analyze it.

Thanks again in advance!
 
Talk to your accountant. It may be better tax wise to finance a new truck and write it off vs. dropping $2k fix an old high mile truck. Figure loss of use from downtime that old high mile vehicles have. Having the pink slip (no payments) for slow times is also something to consider.

Note fluid change is best around 25K miles on this transmission to avoid the above mentioned problems.
 
Note fluid change is best around 25K miles on this transmission to avoid the above mentioned problems.
Working for the DOT, complete and full PM-2s were performed every 20,000 miles.
The transmission pans were dropped and a new filter installed, then topped up with fresh fluid.
that seemed to keep the fluid in the transmissions fluid fresh and bright.
 
P0894 is bad news. P0894 is trans component slipping, aka your torque converter is slipping. When the pcm detects slippage, it codes, enters trans protection mode, and kills the power to the pcs/epc giving max line pressure. Me thinks your trans has seen better days.
 
To bring this up to date,,,,,, couple weeks ago, I took my 2500HD to local shop. Of course he scanned codes, found the P0894 code.

His suggestion was to try a torque converter solenoid with around 60-70% chance this would work. So,,,, that's what he tried. Unfortunately,,,, I fell into the 30-40% range of "not fixing" the problem.

So,,,,, he now suggest, dropping trans, go through clean and inspect (repair whatever's needed) the valve body, flush trans lines and replace torque converter.

I have to say, for parts and labor, I was somewhat surprised. I won't have to refinance the grand kids!!

So,,, that's what we do. I will let you know the next step. Thanks again for past and future help!
 
To bring this up to date,,,,,, couple weeks ago, I took my 2500HD to local shop. Of course he scanned codes, found the P0894 code.

His suggestion was to try a torque converter solenoid with around 60-70% chance this would work. So,,,, that's what he tried. Unfortunately,,,, I fell into the 30-40% range of "not fixing" the problem.

So,,,,, he now suggest, dropping trans, go through clean and inspect (repair whatever's needed) the valve body, flush trans lines and replace torque converter.

I have to say, for parts and labor, I was somewhat surprised. I won't have to refinance the grand kids!!

So,,, that's what we do. I will let you know the next step. Thanks again for past and future help!

Why? Just completely rebuild it. I bet warranty is different (None) as well for a patch job. They have to tear up internal seals to get anywhere in the transmission and it doesn't save much in parts to skimp/skip replacing them. I get my 4L80E transmissions completely rebuilt for ~$1200 and that includes pulling it out and shoving it back in. (Frictions/seals included. Hard parts like gears are extra of course.) Got to shop around including the shops reputation.

FWIW the TCC clutch is also a weak design that doesn't hold well. Last transmission I patched wasn't coding, but, was slipping the TCC bad enough to drop out and try locking again while pulling a hill. I replaced the TCC and front seal with a triple Disc Yank and the problem went away. You may have something else slipping in yours, but, IMO a better TCC clutch is one of the few needed upgrades available for the 4L80E. The Diesel Torque that you don't have is why I make this suggestion so YMMV.
 
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