3-4 harsh shift 4l80e

[AuroraGirl]

This is for my 2005 with 6.0 but has anyone had any experience with the 3-4 shift being harsh? I expect the shift to be harsher under a situation such as WOT and letting off the throttle (letting it shift up to 4) but if i take off from a stop and accelerate with 25-50% throttle till it wants to shift to 4 it usually is harsh. warmed up and cold. It still has the TAP values from my step dad owning it (transmission adaptive pressures) and I was going to throw my scan tool on it and clear it so it learns my throttle usage. Maybe he had a lead foot? all other shifts appear fine including downshifts while stabbing the throttle (such as to pass)

I was wondering if anyone with 4l80e experience have had this or can say if its characteristic? Since squares came with 4l80e's in 1991 I put it here lol

 

[bucket]

How harsh? I've got two and they both have a delayed 3-4 shift when cold, along with being slightly more positive feeling. When warmed up, I'd say the 3-4 shift is still slightly more noticeable than the lower gears.

 

[AuroraGirl]

How harsh? I've got two and they both have a delayed 3-4 shift when cold, along with being slightly more positive feeling. When warmed up, I'd say the 3-4 shift is still slightly more noticeable than the lower gears.

enough that it causes my foot either back off or slam on the accelerator noticably
Its quick tho, I wouldnt describe it as delayed.

 

[bucket]

enough that it causes my foot either back off or slam on the accelerator noticably
Its quick tho, I wouldnt describe it as delayed.

Maybe delayed wasn't the best description. It's not a sloppy shift at all, 3rd gear just holds longer.

 

[NickTransmissions]

This is for my 2005 with 6.0 but has anyone had any experience with the 3-4 shift being harsh? I expect the shift to be harsher under a situation such as WOT and letting off the throttle (letting it shift up to 4) but if i take off from a stop and accelerate with 25-50% throttle till it wants to shift to 4 it usually is harsh. warmed up and cold. It still has the TAP values from my step dad owning it (transmission adaptive pressures) and I was going to throw my scan tool on it and clear it so it learns my throttle usage. Maybe he had a lead foot? all other shifts appear fine including downshifts while stabbing the throttle (such as to pass)

I was wondering if anyone with 4l80e experience have had this or can say if its characteristic? Since squares came with 4l80e's in 1991 I put it here lol

Copy paste of my response to your post on gmt400:

Check for codes, issues with other sensors like the throttle pos sensor, MAF or equivalent and clear the adapts as a first step. If that still makes no difference, drop the pan and remove the valve body. Unbolt the accumulator housing and see if you have a broken 3-4 acc spring...also check the 3-4 shift valve for drag. While it's apart, Id install a Sonnax TCC valve, 1-2/2-3 shift valve spring kit and a Central Valve Bodies drop in oversized AFL valve. Those will address common valve body related issues with the 4L80E.

Note that when you drop the valve body, there will be some check balls that will fall out so you'll need to use assembly lube or petroleum jelly to hold in place for reinstallation of the valve body.

Let me know if you plan on doing this and ill link my 4L80E rebuild video here that covers valve body installation.

 

[AuroraGirl]

resetting the TAPS and driving it mith foot let ups between the 2-3 and 3-4 and I have really frankly not had any hard upshifts. the fluid was changed before as i mentioned and maybe its doing a little cleaning inside? otherweise ive done nothing to it lol. I still need to try to clean the MAF (get a maf code) But .. yeah. when i say smooth i can floor it on a pavement and the 2-3 and 3-4 are smooth

 

[Matt69olds]

I would expect slightly delayed shifts when cold. GM programmed the shift characteristics like that for a reason, they want the oxygen sensor and catalytic converter to get to operating temp as quickly as possible.

 

[AuroraGirl]

I would expect slightly delayed shifts when cold. GM programmed the shift characteristics like that for a reason, they want the oxygen sensor and catalytic converter to get to operating temp as quickly as possible.

yes, when cold it defintiely does that but we havent had a lot of cold weather lately but when it was it would

 

[bucket]

I would expect slightly delayed shifts when cold. GM programmed the shift characteristics like that for a reason, they want the oxygen sensor and catalytic converter to get to operating temp as quickly as possible.

Ok, that's good. It's right in line with both of my 4L80's. Shifting to 4th definitely takes longer when you drive off cold, and it seems like converter lockup doesn't happen until a certain temp is reached.

 

[AuroraGirl]

Ok, that's good. It's right in line with both of my 4L80's. Shifting to 4th definitely takes longer when you drive off cold, and it seems like converter lockup doesn't happen until a certain temp is reached.

the last couple days the temps dropped while at work and it definitely hangs in 3rd and is much more willing to down shift to 3rd from 4th when cold. My trip from work involves a lot of uphill and curves, mild tho not steep, and just the change in load from starting to curve might make it downshift keeping a constant speed
But it wont do that warm

interesting

 

[Blackbeard44]

i know the 4l60's in my trucks wont lockup until transfluid hits 75 degrees, not sure if a 80e is programmed the same tho.

 

[AuroraGirl]

Ok, that's good. It's right in line with both of my 4L80's. Shifting to 4th definitely takes longer when you drive off cold, and it seems like converter lockup doesn't happen until a certain temp is reached.

so I took air box lid off to get maf offf..... I was told the air filter should be Fine LOL! This thing is PACKED. How wwas this truck making power?

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Thats insulation from the firewall, which is almost all gone lol. Mice.

Anyway,.. the MAF i cleaned and it had a lot of dirt on the honey comb and the sensor elements, perhaps poorly sealed filter in housing. Will try driving after new filter lol...

Also,. do you know where this ground strap on the right of the firewall was supposed to go? mine is missing.

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[bucket]

so I took air box lid off to get maf offf..... I was told the air filter should be Fine LOL! This thing is PACKED. How wwas this truck making power?

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Thats insulation from the firewall, which is almost all gone lol. Mice.

Anyway,.. the MAF i cleaned and it had a lot of dirt on the honey comb and the sensor elements, perhaps poorly sealed filter in housing. Will try driving after new filter lol...

Also,. do you know where this ground strap on the right of the firewall was supposed to go? mine is missing.

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The ground strap used to go to a stud on the hood.

 

[AuroraGirl]

The ground strap used to go to a stud on the hood.

Yeah, wonder why thats gone :O
I decided to just air gun the air filter and wait till tomorrow so i can stop at the store and get a new one and then pick up my scripts. And boy did the truck wake the hell up after cleaning that mAF and the air filter. no idea which was the most, probably the air filter (it was BAD) but the MAF is definitely making it more responsive because i took it for a short spin, got it to temp. It fixed my bank lean codes (for now) and my long term fuel trims are under -3 and below 1 which is considered well in spec for a vehicle. Will give it more time, might reset TAPs again if I notice weird behavior.

Also , I have a camshaft code p0342 for the sensor having no signal when its expecting it to, ive heard connectors can be the problem. anyone know where this is on a 2005 vortec 6.0

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also what I assume is my ps oil cooler appears to be pretty rusty and that hose is slipping off. I might replace that since the fluid in the pump is looking gross. I only imagine what that does to hydroboost. can you put an inline filter on the return "output" to the cooler (magnetic) on a hydroboost? Because 160k miles and prob original or basically original Dexron III (Dex VI was yet to be introduced, and Hydroboost definitely was re-spec'ed to GM Power Steering Fluid as was the PS systems)

At least, Im assuimg thats a PS cooler. If its not I dont know what the hell it is lol! Passenger side by rad

 

[AuroraGirl]

@bucket @NickTransmissions

I forgot, I fixed this about a week ago but i figured out why I thought it as a 3-4, then realized it was 2-3

It wasnt the shifts, my TCC Lockup occurs at the same time as the shifts(according to scan tool)
Lightly holding the brake confirms the shifts are actually beautiful(since doing the TAPs reset)

I also finally nailed down the MAF as being bad, I couldnt get proof of it being irrational on my live data or on my freeze frames, but during some accels one day I got to see the value plunge during large throttle openings usually at speed , they would occur so fast and go back but I finally saw it.

So i replaced the MAF with a Delphi. Not an OEM part number Delphi, but a Aftermarket Delphi. Still cost a decent amount (100$) but it was locally in stock.

That made the shifts even softer. However, TCC lockup is still harsh and it has no pattern. It still slips a few RPM which is designed to , not an issue. But my next best guess would be my step dad used some cheap universal ATF last he did it. WHen I can ill do a DEX VI and filter and address the either leaky pan or gasket or whatever lol!

The part that got me about all this is that the TCC lockup occurs DURING 2nd gear and it doesnt wait a second after the shift before applying?