4L60E Shifting issues?

[wlwarnke]

Just recently, after an engine swap (L31 with 411 pcm to 5.3 with green/blue pcm) my 4L60e has started acting up. Specifically, the 2-3 shift seems delayed. It's not slipping, flaring, or anything like that. It just doesn't shift when it is supposed to. For instance, I had the WOT shift set to occur at 6400rpm and 81mph and saw almost 6600 on my tach and 87 on the speedometer.

I lowered the mph down to 75mph and still see the delay. Sometimes at full throttle I just feels late, so I data logged today on a quick drive home from the gym. Nothing full throttle, but just fairly normal driving.

I see the the 2-3 shift commanded, and solenoids transition from off/on to off/off and the "trans current gear" go from 2 to 3 at the correct TPS/MPH but the RPM and Timing (Torque Management) don't respond until seconds later. When it shifts, it's nice and firm and feels normal.

Any insight?

Trans has about 50k miles on it since I built it, and was serviced last summer, fluid is and was clean.


K5_LS_26_ShiftSched.hpt
shift.hpl

[kingtal0n]

All the ECU does is kick the solenoid. The delay afterwards is all internal to the transmission, based on valve movement, pressure, volume flow rate, mods etc..

Delay also depends on rate of change of RPM. For example with 400hp my 4l80e commands 3rd at 5800rpm but the shift happens around 6000. With the boost turned up to 600rwhp the solenoids kicks at the same 5800 but the engine can reach 6200rpm instead before the shift actually happens.

edit adding: Solenoid itself could be weak. Low voltage maybe increase the delay for moving a valve.

[wlwarnke]

For the 2-3 Shift, A solenoid is already off, and B turns off.

What gets me the most is the TM not reducing the timing at the time of the solenoid changing state, instead you see TM when the actual shift occurs.

I want to be absolutely sure that its not a tuning issue before I have to drop the pan.

[wlwarnke]

This was a longer drive with some more data and using HPT to command some shifts.

It seems like there is a fairly consistent delay of 850ms or so, which doesn't sound like a lot actually, but when watching the commanded gear toggle from 2 to 3 on the log, and waiting to feel the shift occur, it's weird.

Maybe I just need to adjust my 2-3 shift curve a little flatter so it feels right, then tweak the WOT tables as required to make the shift happen AT 6400.


shift.hpl

[kingtal0n]

The way TM works is it looks for RPM drop. This is how it knows when the shift actually happens and it can give an error if there is a high stall converter which hides the rpm drop.

You can tell by the 'time of latest shift' stuff. If its reading correctly then the shift is correctly being identified.

850ms seems like a bit of waiting. What is the shift plate drilled to for that gear. What was the clutch pack clearance. Are the filters clear when was the last filter swap. AFL, PR valve, boost valve, all new?

[TheMechanic]

If I had to guess it is a bypassing 2-3 shift valve but you need a good trans guy to do an accurate diagnosis.

[LS ROB]

I could be completely off here as i have never adjusted an automatic transmission but i checked out the log and tune. IF i looked in the right area in the tune, ([ECM] 15110 - Desired Shift Time vs. Torque - Normal: Normal Mode desired shift time) from 2-3 @ 270lbft, shift time showing 0.150 in the tune and your log shows 1.255s in the log, which is over 850ms. IF i've looked at this correctly, your late shift is a little over 1 second. Someone more knowledgeable; please set me straight if i am not on the right track here.

Or was this more so about the TM not pulling the timing until after the shift takes place?

[SiriusC1024]

4L60e's get damaged above 6200rpm. Technically they are only rated to 6000rpm. The input drum distorts due to centrifugal force. This could be affecting the ability of the transmission to shift, especially with that retardedly low shift time.

I clicked through all the trans settings. If you don't know what you're doing it's best to reference a Corvette file. If it's good enough for a Vette it's good enough for your pick em up truck.

[wlwarnke]

I don?t feel like the ?desired shift time? is used for anything unless you have adaptives enabled and I don?t see that enable option in my 2003 tune.

When you said the log showed 1.255s for the shift, that want the recorded shift time, that the time you calculated based on commanded and RPM drop?

My approx .850s was calculated based on commanded and seeing rpm start to drop.

Damage above 6200rpm? I?ve heard that too. I rarely run her up that high. Not a race truck. She?s big.

Fluid and Filter changed last summer, maybe 2500miles. All was clean

When rebuilt (40k or 50k ago) all valves were removed, cleaned, inspected, screens were replaced. I don?t recall which feed holes were drilled. It was a Transgo HD2 (perhaps) kit.

Since the delay to ?initiate? 2-3 shift is consistent, I wonder if it?s always been then and only noticed now because the higher rpm, more powerful, faster revving engine?

At faster acceleration rates, .850ms can be a few mph and several hundred rpm.

I?d love to see a log of someone else?s 4L60e to compare

[LS ROB]

I don?t feel like the ?desired shift time? is used for anything unless you have adaptives enabled and I don?t see that enable option in my 2003 tune.

When you said the log showed 1.255s for the shift, that want the recorded shift time, that the time you calculated based on commanded and RPM drop?

My approx .850s was calculated based on commanded and seeing rpm start to drop.

Damage above 6200rpm? I?ve heard that too. I rarely run her up that high. Not a race truck. She?s big.

Fluid and Filter changed last summer, maybe 2500miles. All was clean

When rebuilt (40k or 50k ago) all valves were removed, cleaned, inspected, screens were replaced. I don?t recall which feed holes were drilled. It was a Transgo HD2 (perhaps) kit.

Since the delay to ?initiate? 2-3 shift is consistent, I wonder if it?s always been then and only noticed now because the higher rpm, more powerful, faster revving engine?

At faster acceleration rates, .850ms can be a few mph and several hundred rpm.

I?d love to see a log of someone else?s 4L60e to compare

I must have misunderstood what the issue was. I was looking at the time from when the shift happens vs when the timing gets pulled and it happens after your rpms start to drop. My apologies.

[kingtal0n]

The calculated shift time is probably after the shift is finished. The start of the RPM drop is where the clutchs may start to drag into the next gear as they come on. So if we figure .850 starting to come on and 1.255 finished that is quite a long time for clutches to drag and a long time waiting for them to come on. Somebody said leaking 2-3 and there are many circuits which can leak to create this symptoms. I would be looking at the trans line pressure before making any radical assessments though.

[wlwarnke]

Looking at the 2-3 shift that occurred at 7:19.361.

From 3rd commanded to seeing rpm start to drop took 880ms
From rpm starting to drop to rpm starting to rise again took 340ms.

That's 1.220 seconds from being commanded to completion.

The shifts themselves feel nice, clean, and snappy. Average Joe, not seeing data, and just driving a vehicle that someone else tuned for them wouldn't even notice something was off.

Since I know MPH and RPM settings, I know, and it freaked me out.

The 1-2 shift just before it was delayed basically nil, and the 3-4 shift directly after, had a 170ms delay.
The 4-3 shift has no delay
The 3-2 shift has no delay
Don't haveany 2-1 shifts due to throttling on this log.

I don't see line pressure being an issue as all the shifts themselves feel snappy. Although I havent had a gauge on it since the initial start up.

Since the 2-3 shift valve doesn't have a spring to return it, I'm guessing it relys stricly on AFL pressure both ways?

From what I understand about the 3-2 valve, which isn't much, is that it makes a small change to how fast it can release 3rd and grab 2nd. It seems to be ON anytime the commanded gear is 3 or 4? I recall this solenoid was different, maybe didn't have a spring in it or something.

For now, I took the 2-3 shift table from 31% and up and started multiplying by .99 until i lost 4 mph on the WOT cells. Then adjusted the WOT tables to match. I have not made any hard pulls yet, but NOT looking at a scanner, and just driving, it feels normal.

Does anyone have a log with the pertinent data to see how their 4L60e shifts?

[HATEHPTUNERS]

If it's only an issue on the 2-3 upshift.. there are several things that come into play here... On a 2-3 upshift, you are using part of the line pressure to push the band servo OFF, and also bringing on the 3-4 clutch pack simultaneously... Part of bringing on the 3-4 clutch pack involves filling the chamber under the 3-4 piston as often the fluid is pushed out the bleed hole by centrifugal force from high RPM while you were spinning the motor up in 1st and 2nd... You are also over-coming the load release springs that are on the perimeter of the clutch 3-4 pack. So, again MULTIPLE things happening on that 2-3 shift. You are also over-coming the spring pressure of the 2-3 accumulator which is on the underside of the band servo. Then... if the 3-4 clutches have started to burn they are going to take longer to actually apply and hold. It's normal that the 2-3 shift is going to be a little later shifting than the other shifts because of the transitions taking place. Also, what was the clearance of the 3-4 clutch pack at time of rebuild.. So many things going on that affect that shift. Also, what did you drill the 3rd feed hole size to on the plate, and what did you drill the band release hole to on the plate? Those 2 feed holes will have a dramatic affect on 2-3 up-shift time. Did you use a boxed shift kit? HD2 or something? For now, for simplicity, just lower your shift MPH, and also your RPM for that specific shift, and/or modify your 2-3 upshift pressure to help reign it in.

[wlwarnke]

Thanks so much for the info!

Boxed kit. Was a Transgo 4L60SK or something along this line. Plate was drilled per instructions.

I set the 3/4 clearance at the low end of the tolerance but don?t recall exact. Again. Years and miles ago. 3/4 set was Alto Power Pack maybe. Had like 8 or 9 steels and clutches and came with some selectable steels to get the stack right. Plus I replaced the top plate because mine was warped slightly. Don?t recall if it was thicker/heavier or of that was an option.

Thanks again for explaining a little more about that particular shift. I knew the band released and the clutches applied but never thought about the actual mechanical process down to the rpm slinging oil out of the drum.

[HATEHPTUNERS]

You did not mention if this has been happening since you rebuilt it, or if it is just a recent thing... If just recent-there are other things to look at... there is a 2-3 ball capsule in the case behind the 2nd and 4th servo. After many years/miles of abuse that metal stamped capsule housing can begin to leak.. When it leaks, it can cause a delayed 2-3 upshift, and if it is leaking a LOT it may cause a 2-3 flare. Just one more thing to think about.

You also do not mention what updates you did to the valve body... That shift kit is sorely lacking what a 4L60E valve body is going to need. Specifically, did you vacuum test the TCC isolator valve, 1-2 accumulator valve, and AFL? What about vacuum testing the lock up solenoid in the pump and the pressure regulator valve? These things are quite often needed/necessary. Lots of reaming and over-size valves, and O-ringed end plugs to get a 4l60E valve body ready for another 100K miles.. What about the 3-2 control valves? Sonnax 2-3 sequence valve? I applaud you home builders who want to tackle these things yourselves, but it is a large investment of capital to buy all the reamers, and over-size valves, and experience, to really make these things last... a line pressure test on the unit could really help point you in the right direction. Specifically what is line pressure doing at the moment the 2-3 shift is commanded? That could really help you figure out if this is an internal issue-or something outside the unit.

Let us know what you find.

[wlwarnke]

Capsule was replaced. No vac testing done. Just basic air checks.

This morning it def seemed to not want to shift above 6k. Had to let off to let it shift.

Not promising feeling.

So, go into it again and try to see what?s up?
Send it out for a proper build?
Order one from reputable builders?
Swap to 80e assuming they don?t have the same issues?

What do you recommend?

I?m not making a ton of power, but these LS engines love rpm.

[kingtal0n]

4l60/700R4 is a more difficult build. 4l60e is Far superior to 4l80e in terms of economy and weight but that is it.
4l80e is much easier to rebuild, large parts, easy snap rings, basic kits, few mods needed. But they are heavy and will reduce economy. And difficult possibly even dangerous to turn the kind of RPM above 6k without expensive lighter parts and other mods. Some people do it but I won't risk it without proper mods, like the scattershield bellhousing and light direct drum and so forth. I would stick to the 60e if you can afford to get a proper unit and intent to keep the RPM higher than 6k.



The builder for 4l60e is
A. Clinebarger
B. Dana at probuilt automatics (700r4l60e.com)

For 4l80e you could probably do yourself if you know the 60e already. Its much easier than the 60.

I would go into your unit and at least pull apart the valve body, see what is going on in the circuit. Could be done from under the car type of stuff. Just looking at the valves might give you some clues. Perhaps the gasket will show you something is condition of check ball orifices etc... inspect carefully. Look for leaking areas.

Might be an easy fix. Without a line pressure gauge you won't know if its something like a clogged filter though which could be easy in the VB.
Also inspect or replace boost valve.

[wlwarnke]

I?ll rig up a gauge I can watch while driving.

When I rebuilt it originally, I used a new plate that was noticeably thicker than the one I removed. I believe it was also transgo along with a .500? boost valve. I def do not recall anything special about the pump rebuild such as a slide spring upgrade.

I?m torn between pulling it and going through it again vs pony up some coin and buy one ready to go. If I recall correctly mine was a 98/99 year model. Anything ?better? about a newer LS design?

Maybe buy an LS core and built it so I can keep driving my Blazer in the mean time?

I really appreciate you letting me pick your brain.

Where are you located? Seem like the type guy a fella could drink a beer with.

[kingtal0n]

Clinebarger is in texas he is the one you want to get ahold of for the type of information and unit you seek

https://bobistheoilguy.com/forums/me...ebarger.61139/

There are many knowledgeable helpful people on (these and other) forums, I believe by working together they can achieve a great success.

I believe that If you have the time and spirit to pursue details and possibly make a few learning mistakes and the space to rip things apart cleanly you can eventually conquer these units with enough time.

[HATEHPTUNERS]

Keep in mind that a 98-99 unit could be two completely different units.. You determine what 4L60E you have by input shaft length.. There is a 298 and a 300MM input shaft. You cannot simply just swap one in place of the other (without extra parts being replaced such as the flywheel for torque converter bolt spacing and the torque converter itself). Most 2000+ units are going to be 300MM (except *some* corvette, Colorado, Canyon, H3, S10's etc

I think this IS something that you can do yourself. I would not want to spend the kind of money that known builders are asking for on a 60E build... Keep that money in your pocket, and we can guide you on what you need to do to fix it... I can provide you a "bullet" valve body ready to bolt on with all of the reaming, and over-size valves done, with O-ringed end plugs, a pump with updated pressure regulator valve (over-size), increased pump pressure regulator spring, and an updated Sonnax TCC valve, and I can also give you guidance on other updates that MUST be done inside the unit for longevity.. However.... in the end..... there is not much you can do to over-come the inherent weakness of the design. You are limited by design with the space for 3rd and 4th clutches.. You can get the Sonnax input drum and put up to 10 (11 if you want to get crazy) 3rd and 4th frictions to try and over-come the lack of friction surface... and that may be the route you want to go. There are MANY known updates to put into the unit to help it last LONGER.. but there is NOTHING on God's green Earth that will ultimately prevent the 60E from coming un-glued over time, or when exposed to enough abuse... Think about that... if there were anyone on this Earth that could build a unit that would last under the most brutal conditions of abuse-that person would be a MUTLI millionaire, and would be retired by now from selling his secrets... You know why that person does not exist? Think it through..... If that person existed wouldn't the world know about him or her by now? If ANYONE could crack the code on building a 60E to handle BIG power and abuse for 10+ years.... well, you can see where this is going. I'm not trying to denigrate anyone who has a reputation for building these units... I'm not trying to bad mouth anyone... I'm just pointing out the facts that no matter WHO builds it.. no matter HOW MUCH you spend... you will still have a unit that IS going to fail... just a little longer down the line than what you currently have. How long? Who knows...

Also... before we go any further.. one of the KEY components to keeping a 60E alive comes back to the tune...... You can pay $10,000 for a "built" 60E and if the tune is stock, or TRASH... guess what happens to your expensive trans? Yep, it's DONE in no time.. You will then blame the builder but in reality-it's not his fault.. You put his product into a position that it CANNOT survive and that's not HIS fault.. IT'S YOURS! You can ask your tuner to tune the trans side and maybe.... maybe.... he has experience and the time to do that... but what does he care if he does not get it right and your unit smokes on the dyno? What does it cost your tuner when your trans goes up in smoke on the dyno? NOTHING... he just looks at you and says "gee, I guess your builder did not build it right"... That's how it happens.. and it's absolute BS!

I've seen it where the customer buys an expensive trans, bolts it in, takes it to the dyno and it is KILLED within a few pulls on the dyno... You want to know how often that happens? A LOT!!!!!!!!!!! The reason is that the unit was NOT tuned properly BEFORE the first pulls on the dyno... that's why. Failure on YOUR part... or the dyno operator doing the tunings' part to properly tune the trans BEFORE the wheels hit the rollers is a HUGE issue. When the trans blows-you want to immediately blame the builder.. NO... NO.... NO..... If YOU did not verify the tune was right.. if YOU did not set up the proper cooling system for the trans. If YOU did not match the gears in the differential to the tire size... If YOU did not match the converter stall speed to the cam specifications.. If YOU did not break the trans in for several hundred miles BEFORE that first dyno attempt..... If the dyno operator tries to LOCK the converter when you have a standard single torque converter clutch inside and BLOWS your converter instantly... you can see where this is going... It's not just the transmission that has to be built right-it's EVERYTHING around, EVERYTHING touching, EVERYTHING controlling, the trans that MUST BE right or it's going to fail.

With that said.. if you want to know what things to put into a 60E to try and get it to last a while.. I can help you with that... As long as YOU understand that ultimately how long it lasts is YOUR responsibility to insure that EVERYTHING else on the car-the entire "SYSTEM" is set up properly to allow the trans to thrive is done... If you can't afford to make the entire SYSTEM right.. then expect the trans is going to continue to fail. Further, even when it is set up "right" the 60E is NOT going to last 100K miles when it is being abused.. Abuse is ANY time you are holding the gas pedal to the floor and allowing the trans to upshift into the next higher gear under FULL THROTTLE conditions.. that IS abuse and it IS going to take a toll on the trans over time.. In the end you are talking about trying to make a moped transmission last in an environment that it was NOT designed for... that's how you need to think about it... a MOPED transmission in a Hayabusa motorcycle.. Will it work short term? Sure.. Can you "beef it up" to last a little longer than a stock moped transmission would last when it is exposed to Hyabusa levels of power-sure you can... But the ending is ALWAYS the same... It is ALWAYS going to fail. If anyone could build one to NOT fail.... they'd be doing it. Jakes transmissions-one of the BEST builders in this country... talk to him about 4L60E's... Richard Holdener.. some love him, some hate him. Regardless of how you feel about him the guy has more time dyno'ing engines and transmissions than any other person I can think of... what are his opinions on the 60E? His exact words "a transmission made of glass". I've been building them for 21 years now and I REFUSE to sell "built" 4L60E's to ANYONE.. EVER... It's the fastest way to ruin your reputation as a builder... Do I know how to build them to last a little longer than a stock unit would last? Of course-the knowledge is widely known across the internet... it's not a big secret... But... getting someone who can set up the entire "SYSTEM" is where the ball gets dropped. Cooling system, tune, gears/tire size, right amount of fluid, converter clearance, stall speed in the torque converter.... it ALL has to be right.. if a single part of the "SYSTEM" is off-it's over.. you have pissed away a bunch of money... and you are going to blame the builder when it is absolutely NOT HIS FAULT.... I'd rather guide someone on their own build for just these reasons... if, or when, it fails... it was YOUR hands that put it together.. and it IS going to fail.. sooner or later, the end result is ALWAYS the same... just understand that going in.. it's the nature of the beast. Would you expect your air filter to last 100K miles? No? Then just understand that just like your air filter, your trans is getting F'ed up every mile you drive it and every time you beat on it and it IS going to need you to pull it out and go through it again more often than you want to. That's reality.

My feelings are that the 80E is a MUCH better candidate to start with-even though it has it's own set of limitations. Because of the heavy internal gear train-they don't like to spin at high RPM without coming unglued. 80E's are HARD on the drive line bushings as a result of this.. The gearing is also a little harder on take off as compared to a 60E. They eat up a little more HP than a 60E does.. Just like the 60E they are susceptible to failure due to INCORRECT/NO TUNING, and inadequate cooling systems. They are heavier over-all, and are just a little lazier on upshifting-both up and down-than the 60E.. Looking past those draw backs-they can be brutally strong when set up properly, unlike the 60E. If you need more information, or help, you can contact me through DM's.. I don't want to get in trouble here on the forums, so I'll stop here.