2DMNFST

iTrader: (16)

Hey guys, I know its not an F-body but I have a 2000 S10 ZR2 with 154k miles and am having some transmission issue with the 4L60E with no SES light or any other cluster lights illuminated. I read through the sticky on trans issues and have been researching this all evening but cannot seem to find anyone with the same symptoms. Basically the truck is my daily and unless I can get it back on the road by Friday I'm going to need to throw the TA together to get to class..

Basically, I was coming home from class this afternoon and it was snowing a little bit so upon pulling into a side street near my house I wanted to see just how slippery if at all the roads were. So I layed into it a little at about 15 MPH. The trans down shifted to first like normal but never up shifted back to 2nd untill I let out completely. Now the trans seems like it is stuck in first, sometimes I can nurse it into going into second but manually shifting does no good and the speedo seems to work fine. The fluid is clean and full, and reverse works as it's supposed to.

Before this issue I had absolutely no trans issues, the truck always shifted smooth with no hesitation or hard shifts and has been well taken care of. From my research it seems that it could be a number of things such as VSS (which I believe is doubful due to the speedo working), a shift solenoid (which is also doubtful due to it being stuck in first, from my understanding a shift solenoid will cause it to stick in second or third), the 2-4 band (which I really can't imagine as I have never had a problem with the trans slipping in any gear), the last thing I recall reading about is the 1-2 shift valve (but again mine is a 2000 and supposedly in 2000 they recieved the updated shift valve, and did not have the issues the 99 and older 4L60E's had).

I tend to believe it is a VSS sensor or maybe even a TPS sensor, I unplugged the battery for the night to let everything reset and will further investigate tomorrow but if anyone has any idea what the issue may be, please do not hesitate to offer a solution.

2DMNFST

iTrader: (16)

Ok I took it out this morning and the truck does indeed shift through all four gears, however, it will not shift out of first until around 2900 rpm and then you must let off of the gas completely (0% throttle input) for about a second and it will shift into second, the same thing happens for third, and simular for fourth. Except with fourth if I give it any noticable throttle, I'd say above 5% or so, it will downshift strait to third. Im starting to think it is a TPS issue, if you guys have any ideas let me know.

Thanks.

99427camaro

iTrader: (1)

sounds like a throttle position sensor

Gilbert@Ace Racing

Well that's a good thing. Indeed a faulty TPS can and will affect shift points. Get a scanner on it and check yours for proper operation... or you can get a digital voltmeter on the signal wire that sends tps info to the pcm. If you go that route, look for a low voltage reading somewhere around .5v -.9 v at 0% throttle and somewhere around 4.7v - 4.9v at WOT. Sweep it slowly to see that it has a very linear increase or decrease in voltage.

I would also suggest taking a long hard look at the speed sensor.

If you can get a scanner on it that would be the way to go. It might even be worth it to find a tranny shop who will diagnose it for you. Most shops do not charge a fee anymore.

Keep us up to date with what you find.... good luck with it!

g

2DMNFST

iTrader: (16)

Well I changed the TPS today with no change in transmission performance, it still does not want to shift until higher in the rpm's with no throttle. So I dont really know where to go from here, I am now leaning towards a shift solenoid being bad, but am not really sure of what the symptoms of a failed shift solenoid are. I may just have to take it to a trans shop tomorrow after class and see what they have to say. Anyone know what a bad shift solenoid will do? I'd really like to figure this out myself, but the trans shop may be where I end up..

Gilbert@Ace Racing

In order for the PCM to command a shift it only needs to see engine rpm, and outputshaft / vehicle speed. The key now is to know whether or not it is indeed commanding those shifts. Unfortunately you need to get that information and determine if it is commanding the shifts. I recommend spending time and money on a proper diagnosis rather than time and money on parts that just might not fix it... ie: the new tps.

Hope that helps.... let us know what the diagnosis is and we can take it from there!

g

2DMNFST

iTrader: (16)

Alright, well I took it to a reputable trans shop in the area and they told me what I kinda figured but didn't really want to hear. The 2-4 band is shot and I'm going to have to have the trans rebuilt to the tune of $2200. I'm thinking about maybe trying to rebuild it myself, are there many special tools needed? How difficult of a job is it? Can I get away with just replacing the 2-4 band or is a full rebuild necessary?

Gilbert@Ace Racing

If this vehicle needs to be up and running soon, I wouldn't attempt the build myself if I were you. At the miles you stated originally, it needs to be gone through completely. If you plan on leaning on it pretty hard, then I would suggest going with a nice performance unit from one of the Sponsors here. But, if it's a stock unit that won't see improved power ranges, then yeah let those guys do it if they have a good reputation in your area.

Glad to see you got it figured out, now you can focus on getting it back on the road!

g

mrvedit

It's unlikely that your trans is in great shape and only the 2-4 band is shot. As mentioned, most likely it needs a complete rebuild. There were several recent threads on the tools needed:

https://ls1tech.com/forums/automatic...-get-them.html

https://ls1tech.com/forums/automatic...lp-needed.html

While I am enjoying "rebuilding" my first two right now, I am doing it for fun, to experiment with the many different parts on the market, and documenting/photographing every step and option with the intention of creating a very detailed thread and perhaps even a video. I would not recommend a newbie rebuild one because they had to, or to save money. There are many things to learn, many parts to buy, options to consider, special tools to buy, and you need experience to determine what hard parts might need replacing.
I am fortunate to have a very friendly trans shop nearby help me out when needed. And I am fortunate to be able to afford the special tools, buy a new valve body, replace any questionable parts, try out three different sun shells, three different 3-4 clutch packs and many Sonnax parts.

The $2200 quoted to you is reasonable, but you might consider a performance unit from one of the sponsors for around $2000 plus perhaps $400 for your shop to install it.

There are many reasons why even the most experienced engine and auto mechanics won't touch a transmission.

Gilbert@Ace Racing

^^^ That's really good information from a novice builder. Glad you chimed in to help the OP make his decision!

g

2DMNFST

iTrader: (16)

Thanks for that info, I don't think I'm going to rebuild the trans myself at this point, but does it make sense for the 2-4 band to be shot but 4th still work fine? I pulled the pan over the weekend and the pan magnet was covered with metal shavings but it was very fine not chunks or anything and with the mileage (154 k) the shavings don't really surprise me. I don't know maybe I'm just a cheap *** and don't wanna put out the cash, I just don't see how my trans goes from performing flawlessly with no slipping, hard shifts, etc. To needing a full rebuild after a short 50% throttle burst in first gear. I'm no trans expert but it does seem kinda odd to me. Is there an actuator that implements the trans to shift 1-2 but doesn't effect the 3-4?

Gilbert@Ace Racing

The key is that if the band is worn or slipping the reality is that it is slipping because the 3/4 clutches have become severely worn. In 4th gear the 3/4 clutches and the band are applied. The band will ordinarily outlive the clutches. Meaning... once the clutches start slipping the band will too.

For that shop, or for us here to say exactly what's falied inside your transmission is absolutely not going to happen. How could we? We get to our diagnosis through experience and a keen understanding of the transmission and how it operates. Nobody has disassembled it for inspection, which is the ultimate diagnosis.

However, what nobody has explained to you yet, and only because of your last post will I add to the discussion that it is not smart for you to spend the money to have someone remove your transmission and make a "patch" repair when the whole unit has 154k miles on it. And with that "patch" repair you get no warranty, but spend many hundreds of dollars in having it torn down and having the band replaced and a few clutches tossed in while they're there.

Your transmission has outlived it's usefulness.

So, the question you really should be asking is where the value is in spending your money moving forward. Are you going to spend $2,200.00 on a ridiculously overpriced stock rebuild? Or are you going to spend your money on a well built transmission that is built by someone who has spent many years perfecting that transmission for similar or less money.

That is what you should be focused on buddy. Point is, your transmission is wounded because it has many miles on it. That's the nature of automatic transmissions. It is what it is my friend.

From here, it's all about budget vs. expectations.

g

2DMNFST

iTrader: (16)

I appreciate the help and all Gilbert but your making extreme assumptions. You make me sound like im some dumb *** or something just because I question the diagnosis of a trans shop unknown to you for believing its a 2-4 band. I simply asked if there is any shot in hell it could be an electronic issue due to how this problem randomly started. And, I get no response on that I just get more BS about a new trans... I know there is such thing as a 1-2 accumulator, and the servo also has some role in the shift. So to just disregard eveeything I have to say is kinda childish on your part.

If the trans is shot then it's going to have to be rebuilt, the shop wanting to do the build will supply a 12 month warrenty. I keep hearing about these cheap 'built' transmissions that sponsers have but I'll be damned if I see any, I hear alot of talk but for a transmission guy maybe you should promote your product a bit. Or maybe its because we look up at the first post and realize oh ****, this is for an s10 why in the world would a car making less then 200 hp / 230 tq need a built 4l60e, and that is where I am at with it.

Look Gilbert I'm not trying to be a dick, it's just I honestly can't afford a to buy a trans nor rebuild my own right now. So if there is any chance it could be something electronic or if someone could expain what the symptoms of a failed accumulator or servo that would be most helpful. If its shot then its shot nothing I can do about it, i'm just looking for more of a response.

mrvedit

I'm no trans expert, but let me take a shot at it...

The accumulators are used to soften the shifts by having a spring loaded piston absorb some of the hydraulic fluid that is activating a clutch. The piston can leak over time, but I don't know if it can leak so much as to prevent a shift. In any case, that would happen very gradually.

The 2-4 band is activated by two pistons in the servo assembly. There is both a 2nd gear piston and a 4th gear piston. Again a severe leak could prevent the band from applying, but that would happen very gradually.

The servo has a shaft which pushes on the 2/4 band on a riveted bracket. I have head of the rivets breaking which would prevent the band from applying correctly. This would be a sudden failure.

My guess, and it is just a guess, is that you accidentally revved the engine/trans higher than ever before and this caused a failure in the trans. I don't see how a high rev could hurt anything electrical like the solenoids. Very likely it caused something to fail a few weeks earlier than it would have otherwise.

If you drop the pan, there is an access hole near the front for viewing the band. With a screwdriver confirm that it is not sloppy loose and can be pushed back and forth a tiny bit.

Also, under the servo is a test hole where you can apply air pressure via an air compressor with a rubber-tipped nozzle. This should apply the 2-4 band.
With the rear wheels off the ground, have a helper confirm that he can turn the drive shaft. Then apply the air pressure and confirm that the drive shaft can no longer be turned; if true the 2-4 band is working to some extent.
If not, the servo or band is shot.
IIRC this test hole applies pressure to the 4th gear servo piston; there could still be something wrong with the 2nd gear servo piston.

Hopefully a trans expert can confirm the accuracy of this post (or correct it).

Good luck.

2DMNFST

iTrader: (16)

mrvedit thanks for taking the time to post that, that is exactly the type of response have been looking for. If I get some time over the weekend I will try and test the servo and see where that leads me.

BuckyGMC

Gentlmen, I have a 2000 Yukon XL with the same exact problem. Took it to a tranny shop, Honest Freind, He hooked it up and said Electronics were fine (After I replaced the Solinoids) I had to be a Clutch issue.. So I pulled it and replaced all Metals and Clutches. replaced the Seals on the Servo as well,, I Put back together and it is doing the Same exact thing. Something in the Valve Body that I am missing?

lt1pwr1

iTrader: (1)

I don't think Gilbert was making the assumptions you accuse him of at all but I will

Maybe you shouldn't have "tested" how snowy the roads were by punching the gas and down shifting that trans. With that kind of mileage extreme downshifts on a 4l60E are not good. If you don't like his advice then pay another shop to diagnose it. Maybe by the third or fourth one you'll finally believe the trans needs to be rebuilt. Then again, maybe not.

94NDTA

Bump, having the exact same issue with a 98 gmc jimmy 4x4. Won't manually shift into 2nd, and has a rebuilt transmission that was just installed, and the issue remains. It is exactly as described. It was taken to a shop, and the suggested a rebuild. Did no good. Tps replaced, neutral safety switch, and to converter.

mrvedit

You say "won't manually shift into 2nd". Just to be clear, do you mean that with the shifter in [D3] or [OD] that it will stay in 1st gear and never ever shifts into 2nd? Or do you mean that when you manually shift from [D1] to [D2] that it will not shift?

If the trans never shifts out of 1st gear and just holds it right up to redline, this is likely an electrical problem. It could be a shift solenoid (A).
However it it seems to shift into Neutral, that is likely a mechanical/internal problem

I would take it to a trans shop and have them test if their scanner can command it into each gear. Does your speedometer work correctly?

got-a-ls1

iTrader: (12)

well this thread is old but i had a trans am with no 2nd gear. chased all kinds of ****. ended up welding a bit on the end of the servo pin and it fixed the problem. band was smoked. didnt slip at all in 4th gear, but apparently the 2nd gear piston doesnt travel as much as the 4th gear in the servo.