Shift Flare on brand new rebuild + MaxLife

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I just put in a newly rebuilt 4L60e in my 06 Chevy Suburban - all kinds of excellent updates, including Borg Warner clutches, aluminum pistons, updated TCC regulator valve, and much more. Filled with MaxLife ATF, and it has a Hayden 679 cooler (bypassing the radiator).

... and yet I'm getting a p0894 "transmission component slipping" on the very first test drive, with noticeable RPM rev when upshifting. WHAT. THE. !@#$ ?

My understanding is that flare is usually caused by incorrect fluid, low fluid, high fluid level, wrong pressure (blocked cooler), or worn out transmission. Clearly not the last item, and the fluid level is perfect. That leaves only "incorrect fluid", or it is a pressure/flow issue.

I am completely puzzled on BOTH fronts here:

1) MaxLife is supposedly great stuff, many 4L60E owners running it with great results.
2) Hayden 679 cooler is also run by 4L60E owners, no issues.

Sure, the Hayden cooler is not advertised as LPD (Low Pressure Drop) like the TruCool has, but still... could this be the problem? Or is full synth really an issue here? The shop that did the rebuild says they use plain Dex III, which is lame considering you can't even get that anymore! I could painstakingly change the MaxLife out for Dex VI... but I seriously do not see WHY I should need to do that, as it is listed as Dex III and Dex VI compatible.

So confused, and very frustrated given the thousands invested here!
 
How far did you drive it on the test? It's possible that there's air bubbles in the torque converter or valve body causing the slipping.
I'd run it through all the gears including reverse, and see if the problem resolves itself...
 
Could be a bad transmission. It is a rebuild, which are normally great, but bad ones can happen. Maxlife should be fine in this application, and when running a rebuilt or remanufactured transmission I would install one oz per qt of lubegard red. Rebuilt is not as good as remanufactured.
 
Maxlife works great in 4L60E's......In fact, 4L60E/700R4 transmissions are NOT in the slightest picky about ATF!!!!

If you have flares on EVERY upshift & setting Component Slip codes......The line pressure needs to be checked like......YESTERDAY!!!!

DO NOT drive the truck 'til Line Pressure Rise is verified!

This is not a Torque Converter filling or Air Bubble problem & most certainly NOT a ATF problem ASSUMING the level is correct....It takes @13 quarts to fill a dry 300mm converter 4L60E with a empty/flushed Rad cooler + stock auxiliary.

The cooler circuit has a internal bypass.....Even if the cooler/s were completely blocked, The trans would behave normally 'til it overheated to the point ATF vented.
 
Thanks for the ideas folks. I will check line pressure next. @clinebarger I am guessing this means you are suspecting a flaw in the rebuild somewhere?

FYI, it locks perfectly fine in gear, it shifts ok when going easy, but when pushing a bit hard (not WOT, but still pretty heavy acceleration) is when the flare will be noticeable.

I didn't install the torque converter but will ask my tech about his install procedure - he should know to fill with fluid first. As for how far was my test drive, it was about a mile down the street.
 
Filling the converter is NOT necessary. The pump will fill the converter through the Regulator Valve.

Without a "charged" converter.....The vehicle will not move.
 
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Originally Posted by roachslayer!


FYI, it locks perfectly fine in gear, it shifts ok when going easy, but when pushing a bit hard (not WOT, but still pretty heavy acceleration) is when the flare will be noticeable.


Even more reason to check Line Rise!
 
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It's been a long time since I've had a GM trans under my care, so I will definitely defer to clinebarger on what you should be checking. But I routinely use MaxLife ATF, and considering it is a Dexron fluid from the word go, will concur that the fluid is not the root cause of your problems. Unless you want to be installing another trans... I'd check and correct the line pressure ASAP. Low line pressure will quickly lunch those 4L60s!
 
When are you getting the flare? All shifts or certain ones?

The only time I experienced flare on my 4L60E was around 160K when one of the check balls was pushing through the separator plate, would flare at the 2-3 shift.

New plate and all is still good at 291K.

Granted this was a pressure loss like others are suggesting, hard to say where it's happening at. But definitely get this sorted ASAP, doesn't take much to smoke the clutches.
 
Thank you all for the comments.

The flare mysteriously disappeared, apparently.

The shop that did the rebuild has my Suburban and said they could not detect a flare (after a test drive). So I came to the shop and rode with them, taking turns driving. Indeed, the flare is gone, at least for the 1-2 and 2-3 shift. I will have to test the 3-4 shift on the freeway later.

How?

When I first posted this, it was maybe 5 miles of test driving after the newly rebuilt trans. Now it's got over 40 on it. The only 2 possibilities I could come up with are:

  • Air was in the system, now purged?
  • Computer had to "relearn" the tolerances of this transmission vs the prior?


This shop told me it takes 500 miles for the computer to completely adjust itself for this. Forgive me if I don't believe in computer relearning... just seems that makes Chevy look way too smart. But the fact is... the flare has subsided after driving it more.

Next Steps:
I will be clearing OBDII and checking for new thrown codes and any human detectable flares and slipping again. Open to other ideas too.
 
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9 times out of 10 if you have flare on the first drive you have a low fluid level. Fluid has to be checked after the fluid is hot so fluid should have been checked AFTER the first drive (shop should have made the first drive and actually tested their work before you got it). I bet all they did was check/add fluid.
 
@stanlee thanks, good to know. I remember checking it before and after I detected the flare, while hot, but not after driving several more miles to the shop... so if it was a purging issue of fluid not getting into some place it was needed right away, that could make sense.
 
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Sadly, this is still unresolved. The transmission shop looked up the p0894 code and of all the resolutions for it, they saw the ECU/PCU was listed. So naturally, being the only thing on the list that is NOT the transmission itself, they pointed at my ECU to blame so as to avoid any responsibility. I obliged, and got a new ECU, and... yep, same codes, same issues. So I am no taking it back to them with the new computer and they will need to take the transmission out and give me a new one. Ugh.

For my own sanity and curiosity, take a look below and tell me what you think. I'd like to understand what is happening so that I can address it with YET ANOTHER REBUILD.

The transmission shifts so smooth you can't even tell it happen. UNTIL, that is, it gets up to temp! Once up to temp (like after 20 min freeway driving), if I immediately go back to stop-n-go in city traffic, I can then feel it "buck" or kick me when shifting from 1-2 or 2-3. But even in town, it goes back to smooth as glass perfect shifting after the trans cools down (no longer on freeway). So it only has an issue at higher temp. What might that mean? FYI: I have a Hayden 697 fin and plate cooler on this, bypassing the stock radiator cooler - the Hayden is big enough to cool a huge rig, so this should be plenty.
 
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Originally Posted by roachslayer
I just put in a newly rebuilt 4L60e in my 06 Chevy Suburban - all kinds of excellent updates, including Borg Warner clutches, aluminum pistons, updated TCC regulator valve, and much more. Filled with MaxLife ATF, and it has a Hayden 679 cooler (bypassing the radiator).

... and yet I'm getting a p0894 "transmission component slipping" on the very first test drive, with noticeable RPM rev when upshifting. WHAT. THE. !@#$ ?

My understanding is that flare is usually caused by incorrect fluid, low fluid, high fluid level, wrong pressure (blocked cooler), or worn out transmission. Clearly not the last item, and the fluid level is perfect. That leaves only "incorrect fluid", or it is a pressure/flow issue.

I am completely puzzled on BOTH fronts here:

1) MaxLife is supposedly great stuff, many 4L60E owners running it with great results.
2) Hayden 679 cooler is also run by 4L60E owners, no issues.

Sure, the Hayden cooler is not advertised as LPD (Low Pressure Drop) like the TruCool has, but still... could this be the problem? Or is full synth really an issue here? The shop that did the rebuild says they use plain Dex III, which is lame considering you can't even get that anymore! I could painstakingly change the MaxLife out for Dex VI... but I seriously do not see WHY I should need to do that, as it is listed as Dex III and Dex VI compatible.

So confused, and very frustrated given the thousands invested here!


Did the shop put the MaxLife ATF fluid in or did you?

Did the shop road test this transmission until the fluid was up to operating temperature?

Did they use the same valvebody from the old transmission? Sometime the valvebodies have to have minor mods when upgrading components.

if the fluid level is correct (checked when very hot), then the problem seems to me to be one of pressures vs. temp. It could be the pump has leakage.

The rebuild shop needs to check pressures when hot and correct this situation.
 
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The trans shop did not do the labor, they only warranty their parts (t-converter and transmission), and they required a new cooler, bypassing the old, and recommended DEX-III or equivalent. I made the call to put MaxLife DEX-III/VI compatible fluid in.

I had a different shop do the labor and they didn't test anything. However, I am working exclusively with the trans shop at this point, including any further work.

The transmission was a rebuild from a different rig than my original (none of my original stuff was used) - not sure about the valvebody... but see below

Fluid does look correct when hot, we checked levels after freeway driving.

My main concern (and why it's worth me posting here) is that they wont check pressure or anything, they'll just grab another unit off the shelf and give it a go... but that's a pretty crude way to solve this, and doesn't answer what went wrong.


Here is everything they claimed went into the rebuild:

All New Gaskets, Seals Metal Clad Seals, Sealing Rings, Paper and Rubber

5 - New Borg Warner Low/Reverse Clutches
4 - New Borg Warner Reverse Input Clutches
5 - New Borg Warner Forward Clutches
2 - New Borg Warner Overrun Clutches
New Borg Warner High Energy 2-4 Band
Late model 3/4 Clutch One Piece Apply Plate
New Teflon Pump Bushing
New Teflon Extension Housing Bushing
New Bronze Front and Rear Stator Bushings
New Bronze Case Bushing
New Thrust Washers
New Pump Vanes
New Pump Guide
New Hardened Pump Rings
New Hardened Spline Sun Shell
New Borg Warner Low/Reverse (Late Model) Sprag
New or Remanufactured Solenoids
New Sonnax TCC Regulator Valve
New Reverse Input Capsule
New Aluminum 1-2 Accumulator Piston
New Aluminum 3-4 Accumulator Piston
New Bonded Pistons
Updates to the Transmission:
Updated TCC Regulator Valve
Sonnax TCC Regulator Valve #77754-04K/77754-03K depending on application, which requires a special reaming tool, that re-bores worn out aluminum 4L60E valve bodies
 
Never did figure out what was wrong with the transmission. I was warrantied a replacement unit and all issues are gone.

Funny, the shop tried to blame everything on me, my vehicle, my mechanic, even my ECU, etc. Nope, something went wonky with their build. My guess is it was either a bad solenoid, or bad valves that weren't actually replaced or upgraded as they claimed.
 
Originally Posted by roachslayer

...My main concern (and why it's worth me posting here) is that they wont check pressure or anything, they'll just grab another unit off the shelf and give it a go... but that's a pretty crude way to solve this, and doesn't answer what went wrong...



That usually tells you they are simply part swapers and don't understand the intricacies of AT's.

I won't deal with a shop that won't tap into the pressure tap points after a rebuild.

The two shops I work with (mainly for formulation testing) have motored test setups and test each rebuild on the test setup.
 
new transmission rebuilds are shedding it's friction materials from the new clutches 'teething in' see this article here:
https://www.trailerlife.com/tech/diy/tranny-filter-tech/

"John G. Eleftherakis and Ibrahim Khalil are not household names, but since the 1980s, they have tested hundreds of transmissions and analyzed thousands of oil samples. These two engineers broke ATF contamination into two categories: Type I and Type II.

Type I is created during manufacturing. Type II is formed during normal break-in and wear and tear. After about 70,000 miles without an oil change, the ATF is a slurry of Type I and II debris, containing approximately 263 milligrams per liter (mg/l) of contaminants that is 90 percent metallic. The particles range in sizes from 5 to 80

microns, about 82 percent of them larger than 5 microns. Most of that passes through the average filter. It can cause sticky valves, cumulative wear and internal leakage. When 100 mg/l was added to the fluid during a test, it took only 750 hours (about 40,000 miles of driving) to seriously degrade transmission operation."


some tranny rebuild shops do add an additive to prevent warranty claims per testimonies here:
https://www.lubegard.com/wp-content/uploads/2018/10/FINAL-FULL-testimonial-book_sm.pdf

smirk2.gif
 
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