Issues with 2nd gear

[Echo]

I have a 4WD 2002 Chevrolet Tahoe with a 5.3L V8 and a 4L60E transmission.

My issue is this.

About a month ago, my transmission started shifting oddly into 2nd gear, I would have to go well over the normal RPM shift range and let off the accelerator for it to shift properly. I'm getting no codes whatsoever, and it seems to shift into 2nd gear from the column, and drive just fine. My first instinct was to do a flush and change out the filter, but the fluid looks nice and red.

I haven't done that yet because I wasn't completely sure that would fix it. I was hoping to gain some insight from the forum and those more experienced with these transmissions before I pulled the trigger on any solutions.

Any ideas?

 

[Miami-Dade]

I have a 4WD 2002 Chevrolet Tahoe with a 5.3L V8 and a 4L60E transmission.

My issue is this.

About a month ago, my transmission started shifting oddly into 3rd gear, I would have to go well over the normal RPM shift range and let off the accelerator for it to shift properly. I'm getting no codes whatsoever, and it seems to shift just fine into third gear from the column. The transmission fluid is a deep brown color, so my first instinct was to do a flush and change out the fluid.

I haven't done that yet because I wasn't completely sure that would fix it. I was hoping to gain some insight from the forum and those more experienced with these transmissions before I pulled the trigger on any solutions.

Any ideas?

Moved you here from 2021+section.

 

[Echo]

Moved you here from 2021+section.

Ah, thank you, didn't realize where I had posted it.

 

[rockola1971]

Your 2-4 band is likely slipping and you arent getting 2nd but actually it is shifting into 3rd since 2nd was skipped. Thats why the rpm's are jumping up. Smell the fluid.

 

[NickTransmissions]

I have a 4WD 2002 Chevrolet Tahoe with a 5.3L V8 and a 4L60E transmission.

My issue is this.

About a month ago, my transmission started shifting oddly into 2nd gear, I would have to go well over the normal RPM shift range and let off the accelerator for it to shift properly. I'm getting no codes whatsoever, and it seems to shift into 2nd gear from the column, and drive just fine. My first instinct was to do a flush and change out the filter, but the fluid looks nice and red.

I haven't done that yet because I wasn't completely sure that would fix it. I was hoping to gain some insight from the forum and those more experienced with these transmissions before I pulled the trigger on any solutions.

Any ideas?

Do you have 4th gear/overdrive? Any issues with reverse?

If your band's fried/shot you wont have either 2ns or 4th gear. If your sun shell fractured/broke, you'll lose 2nd, 4th and reverse.

If your 2nd gear servo piston's sealing rings are worn/flattened, you wont have second but will have fourth assuming the 4th gear servo apply piston's sealing ring is still functioning.

 

[Echo]

No issues with reverse, or 4th. Just shifting into second from first. If I shift directly into second it doesn't do anything out of the ordinary.

 

[NickTransmissions]

No issues with reverse, or 4th. Just shifting into second from first. If I shift directly into second it doesn't do anything out of the ordinary.

Ok...That doesn't quite rule out the band but you can check for excessive servo travel due to a worn band. When the band begins to go, it usually shows up with 2nd gear shortly before 4th goes out. Go underneath with a pry bar and position the pry bar so that the back of the pry bar is on the servo cover and end is anchored on the inside diameter of the trans tunnel so that you can lever the pry bar to push in the servo cover. Servo should only move around 1/16" to 1/8" of an inch. If it's noticeably more than 1/8" the band is worn and it would be best to pull the trans and rebuild it as the 3-4 clutch pack going out is likely the next thing to fail (most of these come in for overhaul due to a burnt 3-4 clutch pack).

I would also drop the pan to inspect the fluid. Just looking at the dip stick won't often tell you much as it doesn't to the bottom where all the sediment and other matter settles out. The fluid can look red on the dipstick but once drained, actually is very dark/black and bottom full of burnt friction material. If you see lots of burnt clutch material, put the pan back on and pull the unit for overhaul.

Having to let off the accelerator to get an automatic transmission to upshift is a common tell-tale sign of worn applied friction elements (clutch discs, bands) in the trans.

Please quote my post in your reply to the thread if you have questions on anything I've mentioned.

 

[Doubeleive]

No issues with reverse, or 4th. Just shifting into second from first. If I shift directly into second it doesn't do anything out of the ordinary.

You might get lucky with just changing the servos I have before.

 

[Echo]

I made it easy on myself, ordered a new performance 4L60E from JEGs for the Tahoe. This will give me an opportunity to get familiar with working on these transmissions, as I will have the old one to bench and work on.

Should I succeed in rebuilding it, I can swap the one in my S10 for the rebuild, and have a spare on standby or to sell.

Any tips, tricks, or links to some transmission swapping tutorials would be greatly appreciated. I've done plenty of motor work, but never messed around with swapping out a transmission.

 

[NickTransmissions]

I made it easy on myself, ordered a new performance 4L60E from JEGs for the Tahoe. This will give me an opportunity to get familiar with working on these transmissions, as I will have the old one to bench and work on.

Should I succeed in rebuilding it, I can swap the one in my S10 for the rebuild, and have a spare on standby or to sell.

Any tips, tricks, or links to some transmission swapping tutorials would be greatly appreciated. I've done plenty of motor work, but never messed around with swapping out a transmission.

Swapping the transmission is easy...In addition to the usual tools, you will want to have a transmission jack (you can make a regular floor jack work but it's not ideal), either a few 12" 1/2 drive extensions or a long 36" extension and wobble 15mm socket for the bell housing-engine block bolt at the 12 o'clock position. Make sure you index your drive shaft(s) before you remove as they have to go on exactly the same way that they came off. Otherwise you'll have a horrible vibration at each differential (not sure if you have a 2wd or 4wd). Lastly, you'll likely need a heat gun to melt all the dialectic grease that has turned into a glue like substance so you can disconnect the MLPS (the large black thing bolted to the transmission and splined onto the selector shaft) from its dual connector. You will want to purchase a new OEM one (if you reinstall your old one and it fails (both P and N) you won't be able to start your truck.

Watch my 4L60E tear down video a couple times shortly before you begin messing with your existing one so you know what to look for, how to inspect the various parts and sub-assemblies as well as what to expect once you begin tearing it apart. PM me if you need any help if/when you cross that bridge. I also have a complete rebuild series on the 4L60E as well as several topical videos covering high performance parts, mods, etc...

ETA: No computer programming or "fast adapts" are necessary. Just fill it up with 12-13 quarts (you wont get all of it in until you actually put it in gear so fill the converter with a quart, pan with 5-6 then fire it up and idle it...DO NOT PUT IT INTO GEAR AT THIS TIME. Check level and add until it wont take any more. Now put it in gear while still up on all four jack stands so you can cycle it through all the gears and enable it to take up the rest of the fluid. The engagement into each gear should be positive and firm but not harsh or jarring.

At this point you should be a quart or two low. Top it off then take it for a test drive.

 

[nonickatall]

If the oil look red, is not burned and there is only that issue with the shifting into second gear while accelerating, while you can shift to second gear manually without problems, i would first look for other electric or control related problems, like a gas pedal or throttle sensor.

I am not common how that is at the gmt820, but i know that from other cars. If you have a dying throttle or gas pedal sensor wich has areas where there is no proper signal then the automatic transmission control unit does probably not know, that it would be the right moment to shift. But if you change acceleration pedal position it knows and shift. And that would probably make as well no error, because the system can not detect that as a false accelerator position.

That is only an idea. But i would check something like this, before i swap the unit.

There is nothing more angry than spend a loz of time and work to find out that it was a simple sensor...

 

[Alex_M]

Unless I'm mistaken, and I don't do a lot of tranny diagnosis so I may be, but it sounds like a stuck check ball in the valve body separator plate to me. If so, ordering a new separator plate and a set of torlon check balls would cure the problem without dropping the trans. I'd put a shift kit and block off the PWM solenoid while I had the valve body out.

 

[NickTransmissions]

Unless I'm mistaken, and I don't do a lot of tranny diagnosis so I may be, but it sounds like a stuck check ball in the valve body separator plate to me. If so, ordering a new separator plate and a set of torlon check balls would cure the problem without dropping the trans. I'd put a shift kit and block off the PWM solenoid while I had the valve body out.

Typically, a stuck #8 check ball (the 1-2 check ball location) results in a very late, harsh 1-2 shift where I believe he's experience a neutral condition in second until the RPMs prompt the 2-3 shift (though @Echo can clarify if need be). Broken 1-2 accumulator springs can also produce that condition as can a worn PWM reg valve, which if that's the cause, DTC P1870 will usually set after two consecutive drive cycles where the condition manifests.

That said, your post is still a great call out as the plate can be repaired via installation of a metal sleeve from Fitzall's plate repair kit and many aren't aware of that check and fix.

I do this all the time on otherwise serviceable spacer plates. If he ends up dropping the pan, VB and spacer plate, he can proactively repair the plate via a sleeve from that kit (if it's not already worn) and install the larger torlon check ball that comes in Transgo's SK4L60E shift kit as well as convert the PWM to 'on-off' using the Transgo PWM valve. Another thing that can be done is blocking the 3-2 downshift valve for much crisper 3-2 downshifts. The SK4L60E doesn't provide a spring for that (the 4L60E HD2 kit does but it's a lot more expensive) but he can use an extra boost valve spring (the small inner spring) or even an aluminum or steel spacer if he's got the tooling to make one. He can also install the Corvette second gear servo to further bolster the 1-2 shift.

He can perform an air check on the 2nd apply once the VB and plate are removed - I show this in one my 4L60E rebuild videos at 4:57.

If none of those things work, its time to pull and overhaul it.

 

[Alex_M]

Typically, a stuck #8 check ball (the 1-2 check ball location) results in a very late, harsh 1-2 shift where I believe he's experience a neutral condition in second until the RPMs prompt the 2-3 shift (though @Echo can clarify if need be). Broken 1-2 accumulator springs can also produce that condition as can a worn PWM reg valve, which if that's the cause, DTC P1870 will usually set after two consecutive drive cycles where the condition manifests.

That said, your post is still a great call out as the plate can be repaired via installation of a metal sleeve from Fitzall's plate repair kit and many aren't aware of that check and fix.

I do this all the time on otherwise serviceable spacer plates. If he ends up dropping the pan, VB and spacer plate, he can proactively repair the plate via a sleeve from that kit (if it's not already worn) and install the larger torlon check ball that comes in Transgo's SK4L60E shift kit as well as convert the PWM to 'on-off' using the Transgo PWM valve. Another thing that can be done is blocking the 3-2 downshift valve for much crisper 3-2 downshifts. The SK4L60E doesn't provide a spring for that (the 4L60E HD2 kit does but it's a lot more expensive) but he can use an extra boost valve spring (the small inner spring) or even an aluminum or steel spacer if he's got the tooling to make one. He can also install the Corvette second gear servo to further bolster the 1-2 shift.

He can perform an air check on the 2nd apply once the VB and plate are removed - I show this in one my 4L60E rebuild videos at 4:57.

If none of those things work, its time to pull and overhaul it.

Awesome info, thanks Nick!

 

[NickTransmissions]

Awesome info, thanks Nick!

You're welcome, Alex!

 

[Mudsport96]

Sounds much like the 60e in my Silverado. Would take 2nd with a manual selection and 4th was okay. But the 2-4 band was shot. Just enough grip that the extra apply for 4th would hold while cruising.

 

[rockola1971]

Sounds much like the 60e in my Silverado. Would take 2nd with a manual selection and 4th was okay. But the 2-4 band was shot. Just enough grip that the extra apply for 4th would hold while cruising.

But the minute you leaned into the throttle even somewhat moderately 4th(OD) would turn to neutral and the RPM's would skyrocket, right?

 

[Mudsport96]

But the minute you leaned into the throttle even somewhat moderately 4th(OD) would turn to neutral and the RPM's would skyrocket, right?

Believe it or not it would hold fine under moderate tip-in. And just kick down to 3rd with any more throttle.
This truck has always shifted odd. To the point that the very reputable shop that installed the new Trans kept it an extra day trying to troubleshoot a perceived issue that 3 different 4l60es have had in it. So I am confident it is a programming issue. I could go into more but not wanting to pirate a thread.