It's a long read, but I promise it's all relevant information.This one has me banging my head against the wall. Not a first time builder, but don't run a shop either.

Did a trans for a buddy of mine. The plan was to put it behind his turbo 5.3 pickup. 2002 silverado 4wd, 4l60e.

Rebuilt it to the same (or better) specs than my camaro got. 8 clutch bw Hi energy 3/4, .500 boost valve, transgo hd2, 5 pinion planets, extra wide carbon 2/4 band, "corvette" servo, deep truck pan (stock), etc.

After rebuild the truck would start in 2nd, and flare the 2/3 shift when under decent load. Very light throttle and it will shift ok but anything over about 1/4 and it flares. No 1st, no 4th. Reverse is fine.

Hooked up fancy snap on scan tool and checked that the computer is commanding gears...it is...so the typical fix would be shift solenoid "A"
So, drop the pan to check, voltages across the solenoids look fine, so i figure it could be the screen, so we replace it anyway. Use the scanner to force the solenoids and I can hear them click if i hold a stethoscope to the bottom of the pan. truck acts the same anyway...next step

Buy a brand new ac delco pressure switch and install it...same story, truck still hates us.

Read through the forums, scour the tech manual, and decide that pulling the pan one more time is no big deal. Check the accumulator for cracks or leaks and all looks good. Change up the springs in there to the "stiff" shifts anyway just to try a new change. Truck STILL hates us ughhhh

So, screw it, pull the whole trans. Tear it apart and the spring in the low/reverse clutch piston has coned the snap ring surface of the spring, clutches are wiped out. Go through the whole thing and nothing else is out of line. Buy new piston, spring, clutches, steels, snap ring, and seals.

Double check everything in the valve body, every piece gets washed, new paper rubber kit through the whole thing. So, now it's a whole new trans.

Double check all electrical connectors, fill with fluid, say short prayer (ok it was a long prayer), take it for a drive. Pull out of the shop in what felt 100% like first gear. This is a heavy truck and 2nd gear starts are pretty noticible, and for once, it didn't do it. So, hopes are high, but i'm not gonna get ahead of myself here. Take it down the road nice and easy, get 2nd, 3rd, and a late 4th gear. seemed about 500rpm after it should've...but I got it none the less. Hit the first corner I come to, pull off to check fluid, all is well. Back up to turn around, reverse is good. Go to leave in OD...no 1st.

Put it into manual 1 on the column (linkage is properly adjusted) and still, it starts in 2nd. put it in 2nd, starts in 2nd. Put it in D(3), starts in 2nd. Make it the mile or less back to the shop, park the thing, curse a few times, decide to leave it alone.

WHAT IS GOING ON?? Been through more then 50 of these and there was obviously a learning curve on the first 2 or 3, but they've all ended up reliably on the road, and the rest have been smooth sailing. I find it hard to believe it was something I did 2 times in a row with this one. Not trying to throw blame elsewhere, I just want to get the thing fixed, its a mission at this point.

The truck was previously tuned by Black Bear via email but has since been flashed back to factory tune by them as well.

I'm at a loss for what to check, what to change, what to fix, and I'm hoping someone on here can be my saving grace. pic of the spring that broke. The 4 little tabs the retainer ring catches on arent holding because the entire face is coned out.

 

The low/reverse clutches are the ones that fit directly into the case, right?

Is it possible the case got nicked/bent/etc when the low/reverse clutches originally went out and that's preventing them from properly applying in 1st?

Can reverse still work if the low/reverse clutches don't apply, only the reverse clutch? Because that's the only commonality and difference between 1st and reverse I see in the 4l60e service manual. If the reverse clutch to give reverse despite the low/reverse clutch not working, that could explain why you have reverse but not 1st due to a low/reverse clutch issue.


But now that I think about it after typing that out, I have no idea how to explain why it starts in second in OD, manual first, and manual third.

 

I just built a 4L60E last weekend and had almost the same symptoms. 2nd gear starts, it would shift into 4th though. I was testing with the truck still on jack stands so there was no load on the trans. My dyslexia kicked in on assembly and I installed the 1-2 shift valve and spring backwards. I remove the valve body installed the spring first and then the valve and all is good now.

 

Im no internal trans guru but I know there is a no 1st 4th lockup limp mode that can be induced by the computer. Is it throwing any codes?

 

The first time the issue arose, it threw a code for the 1/2 shift solenoid. Used the snap on scanner, tested it with the pan off, finally replaced it to no avail. It has not thrown any codes since that 1.

 

This raises a red flag. Why did that happen? There shouldn't be enough travel in that clutch to ruin the spring retainer.

Most of the time a second gear start is caused by low pressure. You didn't say anything about checking pressure.

Could have the wrong 1-2 shift valve spring (too stiff)

Blocked or clogged solenoid feed holes. Should be 1/32" no bigger, no smaller.

1-2 solenoid clip in the wrong groove, leaking o-ring. Causes 2nd start and no 4th.

Somehow the 3-2 and pwm solenoids could be swapped.

Converter regulator valve installed wrong.

Low valve body bolt torque.

Mismatched VB plate/gasket.

Rare, but could be a broken wall in the case worm tracks near the manual valve.

Reverse abuse roll pin not installed in hole in the divider.

 

So what did you end up finding?

 

I never read this thread before.
I am curious, as there are multiple possibilities for a cause or multiple causes...

Is this unit long gone by now?
I would have to ask a ton of questions otherwise to troubleshoot.

 

Oh man do I remember this trans. Up to this point I had a mixture of good luck, and mainly stock units. I hadn't had many issues at all but I'm actually very greatful for this issue because it catapulted me into a huge learning curve. I stopped focusing all my energy on the "hard parts" and turned the focus to the oil. Since then, I've definitely learned alot and have so much better of an understanding on how the 4l60e works.
Anywho...
Really was banging my head against the wall. Built a new valve body, swapped it in, and all was well.
This was before I had my own shop, thus I had no vacuum tester. So, I took it to a shop and had them check it.
Turned out just being a GARBAGE afl valve.
Wouldn't make enough AFL pressure to stroke the 1-2 shift valve against spring pressure even when the solenoid was on.

t would start in 2nd because 1st gear solenoid strategy is to have both solenoids ON and 2nd gear has the 1-2 OFF and the 2-3 ON.

Since the 2-3 doesn't have to stroke against spring pressure, it could still move, but the 1-2 wasn't moving. So the VALVE strategy was 1-2 OFF and 2-3 ON aka 2nd gear valve positions.

the 3rd gear shift was soft because with no AFL pressure, you aren't getting adequate line rise.

Didn't have 4th gear because the 1-2 solenoid is ON for 4th...and again, there wasn't enough pressure to stroke the valve against the spring.

I've actually seen this same set of symptoms come from another local guy and had to diagnose/fix and did the exact same thing, confirming my thoughts. Turned out just being a GARBAGE afl valve. Wouldn't make enough AFL pressure to stroke shift valves when the solenoids were on. Reamed that one and all was fine.

For anyone reading in the future, if you're unable to Vaccuum test, here's a couple things you can try.
1. Find a local trans shop and ask if they will vacuum test it for you. This is always better than shooting in the dark. If it tests bad, they likely can do the Sonnax Valve setup for you for a fee. (don't expect them to gaurantee/warranty anything)
2. Transgo will soon be releasing a ream and fix kit for this valve...should be quite a bit cheaper than the sonnax setup.
3. If you want to just bandaid the issue, you can force some extra AFL pressure. Easy way to do this is to remove the spring and Block the 3-2 downshift valve inboard. I make an aluminum spacer but using a 7/8" long piece of 3/8" brake line would work fine. Take the spring you just removed, and put it Inside the AFL spring.
4.You can also use a 5/64" drill bit to open up the holes that feed the shift solenoids. This will supply them with more oil if the pressure is still too low. I would not do this unless you've already tried #3 and still have issues. If you have adequate AFL pressure and drill these holes, you could supply more oil than the solenoids can exhaust, and you'll just cause other issues.

Options 3 and 4 are not really fixes. They make get your vehicle down the road for a while, but it is just masking underlying issues.

 

Thank you for the explanation Maroon Monster.

Very good recommendations as usual!

Interesting news regarding TransGo... I am happy with the bulk Sonnax repair sets though.

Actually #3 is some what commonly done.
I am not a fan of #4 but you stated why it is a bad idea at the end of your post.

Also, I PMed you some questions about your library needs.

 

Agreed. #3 is commonly done. Transgo actually has you do it in every kit (I think...I haven't used one in a while)
But, it's still just covering up the fact that the AFL is leaking.

Now, I still do it even after reaming, but that's because I wan't more feedback at the boost valve for any given epc amperage.

 

I totally agree.

Honestly the 4L60E valve-bodies are leaky junk once a relatively low amount of miles are on the unit.
Later valve-bodies are not as bad, but...
The amount of circuit leaks in these units are ridiculous!
DIYers have no clue just how badly and how many locations leak. We are lucky that most of the leaks are very easily fixed (mostly due to Sonnax).

I am soo happy that I was on the 4L80E crew. The repair engineers for the 4L60E have permanent nightmares about the transmission.

Even though the 4L80E valve-bodies still have some leaks as well... It is no comparison to the 60 units.
The 80 valve-body is by far my favorite GM design!

 

Thanks for the nearly useless accumulator control valve in the 80e. It's been "conveniently re-purposed"

Also...shame on you for not using the full apply area of the direct piston

 

LOL! best dis I have heard in a very long time!

Me =