Another 4L80E Question from a GMT400 Newbie

[TR185]

I've had my truck for around three weeks now, and it's the first vehicle I've ever owned with a 4L80E. I've owned a couple S10 Blazers with the 4L60E but that's the closest I've been to one. Just came from a Dodge Durango with an automatic and it has some weird shifts to it. (What do you expect, it's a Dodge?)

Before that, mainly had manuals.

So now, my questions:

What should I expect with shifts as far as how they feel?

How does a Lock Up Torque Converter work?

First and Second feel pretty close together, then takes a little time to get to third (No slipping or high revs), then I assume fourth, then the lock up comes?

It seems like my fourth and lock up are kind of sporadic, they usually hit at the same RPM's, but speed varies. Lock up disengage when you hit the brakes?

Fluid looks and smells good. PO did a fluid and filter change about 5,000 miles ago. Any tips or am I just paranoid?

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[Jrgunn5150]

The 4L80 does kind of stack shifts, or shift quickly, mine does it and it's brand new lol.

It only locks in fourth, no third lockup like other models. It only locks above 58 mph, and will unlock if you hit the brakes, or throttle over 15%. I think your speed can drop to 45 or so in lockup however.

 

[TR185]

I think mine locks up before 58 MPH. I'd have to drive it and see. Could that be caused by a wiring issue or would it point to a straight torque converter problem?

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[TR185]

I think mine locks up before 58 MPH. I'd have to drive it and see. Could that be caused by a wiring issue or would it point to a straight torque converter problem?

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Actually, I'm positive that it locks up before 58 MPH because my ride to work is 55 MPH speed limit and it locks up. I can cruise 55-60 at around 1900 RPM's. Give or take a little.

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[Jrgunn5150]

I'll have to double check my manual, I've seen lockup at less speed on mine as well, but not much.

 

[TR185]

I'll have to double check my manual, I've seen lockup at less speed on mine as well, but not much.

My exhaust makes all my shifts sound weird too, PO had stock exhaust all the way to two glass packs with no tips on them or anything.

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[Jrgunn5150]

Here's the factory service manual for it, https://www.dropbox.com/s/h7ckb9edafc7cgd/4L80E.pdf

 

[MIHELA]

I have the BMHM tune in front of me in TunerPro and it says lockup can occur in 3rd at 42mph and same in 4th, at 0% TPS. 2nd is set at 127.5, an unattainable combination. In theory you could tune it to lock in 2nd.

 

[Justin S]

Nv4500 swap

 

[TR185]

Nv4500 swap

I wish... don't have the funds or the time right now

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