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4L60E - broken 3-4 accum. spring & check ball question

42K views 21 replies 5 participants last post by  sabino56 
#1 ·
I dropped pan and removed valve body with tranny in truck on a 4L60E from a 93 Suburban. I found a broken spring in the 3-4 accumulator. Two problems & questions.
1) I kept 7 check balls in valve body, no problem. 2 check balls fell when I removed the separator plate from case. Problem is - both are the same size as all the others. I understand there should be a larger check ball from the 1-2 accumulator area -but I can't find it. I see that there are two check balls in case in holders #10 and #9 in pic attached. I can see that the ball is not in #10 but I read that it's not likely the ball in the holder in #9 will come out. Is this true? I can't easily see if the ball is there. Two possibilities - the small ball came from #10 location and the holder is broken/bad? and I lost the bigger ball - oR - the small ball cam from the 1-2 accumulator area instead of the larger ball. (doesn't seem likely..) I'd appreciate advice.

2) The 3-4 accumulator spring which is broken appears to be "plain" colored.
I have Helm shop manual which lists the color for 1-2, & 3-4 accumulator springs based on transmission model. Problem is - the code stamped on my transmission is "WRD" - it's not one of the models in the book. If I want to keep the stock/OEM shift - what spring color should I put into the 3-4 (& 1-2) accumulators.

Thanks for help
 
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#2 ·
OK, I don't think I'm crazy

When I posted this last night, I was tired & frustrated and I know it seemed kind of lame. "What happened to the bigger checkball?" - you lost it, idiot.
However, I don't think I did!
I knew there were checkballs above spacer plate which had to be accounted for and replaced so I was careful to have a pan to catch whatever fell. This is how I found the balls I did find - I heard them drop and found them.
This morning, I went out and got under car with better light and a magnifier to help the old eyes. I could clearly see that the checkball in the #10 location on the diagram below was not there - 1 checkball accounted for. The other was harder to see but I was able with a penlight and magnifier and a pick clearly see the checkball was still in holder and could move it up/down with pick. So the ball in the #7 location was still present in case. That leaves only the checkball in the #1 location which is supposed to be a bigger ball. I have pic below of the checkballs which dropped and they are same size.
I was very careful on removing the valve body and I've counted the checkballs over and over to make sure none are missing there (7). pic below.

I bought the vehicle new and only have had the transmission serviced twice. Once to change the transmission fluid and once to have a solenoid replaced. Both services were done by dealers.
So I'm confused - I don't think you have to pull valve body to replace solenoid so I doubt a mistake would have been made then.
Has anyone ever heard of a small balls being put in transmissions at position #1 from factor? Other ?
I appreciate any help/advice
 

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#3 ·
Well, there are only 7 check balls that go in the valve body against the separator plate. Then ON TOP of the separator plate between the plate & case, there is 1 check ball that you have to put back. There are 2 captured balls-1 in the 2-3 ball capsule up inside the 2nd & 4th servo housing which is accessible only with the valve body removed, and a 2nd ball capsule by the low/reverse piston feed. So you should only have had 1 check ball come out from between the separator plate & case. If you had more than 1 come out, then look carefully at the other 2 locations I've mentioned.

All check balls will be the same size. .250" or 1/4". There is no larger check ball for the 1-2 unless someone has rebuilt the trans and put a larger check ball there. That is the shade tree way of doing it as there are separator plate repair kits, and/or new plates can be installed from Trans-Go.

On your 3-4 accumulator, you do realize that you can eliminate that circuit right? When you eliminate the circuit you can leave out the piston, pin, & check ball (the one on TOP of the plate).
 
#4 ·
Thanks for answer. I found that one checkball came from the capsule by the low/reverse piston feed (the #10 location in the diagram). The other was still in place. My confusion was the HELM manual and some stuff online was saying the one checkball which you would expect to drop out should be a different size and the one I had was the same as the others. I stopped by local tranny supply and got same answer as yours - all the balls are the same size. So that confusion is now cleared up.
I didn't know about potentially eliminating the 3-4 accumulator. The reason I pulled it apart was I was having very hard shifts from 1 to 2. I expected to find the spring broken on the 1-2 accumulator. I didn't - but the gasket on the separator plate was sold old it chip/flaked off removing the 1-2 housing I had to pull the valve body to replace - and I found the 3-4 spring was broken. I don't know why this would cause or if it was the cause of the hard 1-2 shift - but I think I'll try to put everything back as stock and see what happens.
I only could find "purple" accumulator springs here. The springs that came out are plain. The transmission supply Transtar here said that's all they stock and all the local shops use. I'd have to order the plain springs. Any reason to care?
 
#5 ·
Check your separator plate carefully where the 1-2 check ball hits the plate. Common for the hole in the plate to be enlarged from continuous assault by the check ball. If the hole is enlarged, install a plate saver, or install a new plate.

Pull the piston out of the 1-2 accumulator housing and check the spring. If it is good, then look carefully at the fit between the pin and the bore in the piston. It's common for the bore in the piston to wear. I would highly recommend that you install a new accumulator piston if you think it has a lot of miles on it. Same for the 3-4 piston (unless you are deleting that circuit?).
 
#8 ·
Thanks I appreciate the help.
I'll check the plate hole at the 1-2 checkball and the clearances on the servo pistons. I did check when removing the pistons they moved smoothly with just a little drag. I was planning to just replace the o-rings on them if there isn't too much wear.

There is another piston/spring accumulator on the end of the valve body - in the manual I have it's called the "forward accumulator". While I'm to this point do you recommend pulling that off and checking? I wasn't able to find parts for it at local shop so I haven't pulled it off.

as far as 3-4 accumulator - just curious as to why you recommend deleting spring? For performance, tighter shifts? or however it modulates the 3-4 shift isn't worth the potential for it to break/fail?
 
#9 ·
The reason you want to delete 3-4 accumulation is it is a potential leak point. A leak point that can cause a failure, then a melt down, and then a costly rebuild. You will not notice any difference between a trans with 3-4 accum. deletion, compared to one that still has 3-4 accum. active. Further, if you are going to delete it, I would highly recommend that you BLOCK THE FEEDHOLE. The other methods of locking it out using washers, or just leaving the spring out still leave a potential for pressure loss around the sealing ring of the piston, and the piston pin bore. Completely delete the circuit, and all potential leak points, by plugging the feed hole in the case. If you plug the feedhole, you can then leave the piston, pin, and 3-4 accumulator check-ball out entirely. There is no need for the dead weight! Your ET will pick up .000000001 of a second with this mod! Yeah baby! (Attempted humor there at the end).
 
#10 ·
Ok - thanks. makes sense.
The reason I got into here was because it had a hard or bang shift between 1-2. I expected to find the 1-2 spring broken based on what I read - but it was OK and the 3-4 spring was bad. From what I've heard, the 3-4 broken spring is not likely the cause of a hard 1-2 shift. So - any thoughts on what I should check while I have it out would be appreciated. I read one of the checkballs affects the 1-2 shift so I'll make sure to look at plate hole at check balls to be sure they look OK. And I'll look at clearance/wear on 1-2 piston.
 
#11 ·
Hmm.. Hard 1-2 shifts... Let me think about this.. Check the feed restriction hole in the sep. plate for 1-2 and see if it has been drilled. If someone has done a shift kit-either commercial, or shade-tree-and they have drilled the feed restriction that would cause a harsh 1-2. Check for a Corvette servo. Check to make sure that someone has not pressed a check-ball into the feed hole for the 1-2 accumulator housing. Those are about the only things I can think of that would cause a harsh 1-2 shift. If ALL shifts are hard, I would suspect that maybe something has been done to increase line pressure. However, if it's just the 1-2 check those things I've mentioned.

You are right, the broken spring for 3-4 accumulator has no bearing on the firmness of the 1-2 shift.

I will post a pic in just a second that may show you where the problem is..
 
#12 ·
https://www.google.com/search?hl=en...up-the-4l60e-transmission-for-towing;1214;729

If you look at the "Accumulator Valve & sleeve" in this pic.. It has the numbers 4-4@740 in front of it. You need to use a pick and stroke that valve to make sure that it is NOT stuck. If it is stuck/sticking it will cause the harsh 1-2 shift that you are describing (if it's not one of the other things I've listed above).

You can pull the pin out that is holding the sleeve in. Then pull the sleeve out by using a hooked pick to reach in there and grab ahold of the leading edge of the sleeve. Once the sleeve is out you can clean the sleeve thoroughly and the valve as well. Put it back together (don't forget the spring!), put the pin back in. You just want to be sure that the valve slides easily inside the sleeve. If the valve is sticking/stuck it is because there is dirt/debris wedged in there between the valve & sleeve.
 
#13 ·
usually a hard 1-2 is caused by a worn tcc valve the ecm will increase line psi to compensate for the leakage in that circuit sonnax sells a valve but the vb needs bored with a reamer and blocking the 3-4 will build more psi on the 3-4 shift it will not be harsh but quicker just do not change the 1-2 it will greatly affect the firmness
 
#14 ·
Thanks for things to check. I am the one/only owner of the vehicle. Bought it new and have never had anything done to it but change fluid and change a solenoid once. So - there aren't any mods.
I'll check the accumulator valve/sleeve & take a look at the TCC also. I had found the SONAX site. Interesting you can enter a "symptom" and it highlighted these two things. I think the best description matching my problem is the "bang" at light throttle - it doesn't seem as bad at heavy load. Regardless - I'll take a look at both + previous suggestions. It's not worth doing much more than attempting to clean up, make sure it's not sticking, etc. If TCC, I wouldn't spend $/time/effort for reaming, etc. This is just my dump & hardware store truck - I'll live with the bang until something breaks and have it rebuilt. It has 190k on it, amazing nothing more significant has failed.
 
#15 ·
Josh is right on the money. I forget about those issues as we always install a Trans-go kit in every 60E rebuild that addresses those specific issues (ream the bore, and larger TCC/ISo valve) so we never see the harsh 1-2 shifts after rebuild. I have never had a customer come in complaining just about a harsh 1-2 either. Normally by the time we see 4L60E's it's for much more than a bang shift...

Sabino, if you wanted to try swapping valve bodies I could "fix" one for you with the Sonnax valve and ship it out to you. I don't want/need your old VB as it's not worth the shipping to get it back here. Contact me through PM if interested.
 
#16 ·
I appreciate the offer but I think I'll put this back and see how it goes for now. I want to put it back together this weekend as I have some other, more interesting projects I want to get going. I was just trying to get truck to run a bit better as I need to run up to Phoenix to get some parts for an old camaro. As I said, this truck has one wheel in the junk yard and it's kind of silly for me to even be messing with it. I told my girlfriend - some people to crossword puzzles - I mess with cars.

I did check the accumulator valve with a pick and it moves easy and smooth. However, I think the likely problem is the 1-2 accumulator. I mic'd the OD of both 1-2 & 2-3 and both were 9 thousand under 2". However - the ID of the 1-2 piston is much looser than the 3-4 and can **** on the pin quite a bit. I also see a bit of scarring on the bore of the 1-2 accumulator housing which probably goes along with the sloppy ID to pin clearance. The seal is looser also - the 1-2 piston will fall out of the housing while if I put the 3-4 into it I have to use air pressure to pop it out (even though the ODs of piston is the same for some reason the seal is tighter - maybe because it hasn't been moving with a broken spring forever..) So - I'll see if I can pick up a 1-2 new piston/housing for a reasonable price tomorrow - or I'll just put it back together as is and live with it. We'll see how it goes.
 
#17 ·
Kawabuggy i seen u stated u use trans go kits brings up a issue im having i have one getting a 1870 code and harsh shifts after a rebuild with t go kit thinking iso bore is worn so bad its leaking past it even thought they say the valve in the kit save worn vb i was using sonnax kit with the reamer until i seen t go has the valve in there orange box kit been usuing it on many units with great results but this one is a exception
 
#18 ·
connector

I'm sorry to ask one more thing.
The retention clips on the solenoid connectors broke when I was disconnecting the connector. I can only find a complete wire harness for $65 which is too much. These were so fragile after all these years, I have to believe it's not too unusual to break. What do people do in this event? are there replacements somewhere? just plug them back without the little retention clip? wire tie them in place?, other?
 
#19 ·
I just plug em back in if the clip is broke....use little zip ties, if possible, in aiding it in holding if the ties will be effective.If not,don't worry about it....I wet scotchbrite all the accumulator housing bores to clean up the small scratch marks before re-assembly also.
 
#20 ·
The 60E wiring harnesses should only run $35 from Rostra. You can get used GM harnesses (that ARE serviceable, and not brittle) for $20. If you need either one, just let me know & I can ship them to you.

On the accumulator bores, you can use the 3 finger style (stones) brake hones to run up & down in the bores to remove high spots, and minor scoring. Or, I can sell you a new 1-2 housing, with new piston & seal, for $15.

Josh, what year 60E are you working on? Recent build? Did you replace the converter? Did you replace TCC solenoid, or TCC PWM solenoid? Was the cooler flushed, and/or tested for flow? At this point, if I were you, I would disable TCC PWM so that the converter is either on, or off, with no modulation. That should solve the 1870 code. If it does not, then there are many other things that will need to be checked. Are you sure you used the correct gaskets? If the TCC solenoid is not sealing properly internally it will set the code as well. You can replace the wiring harness with another one (TCC solenoid is part of harness), or you can purchase just the TCC solenoid separately and replace it using wiring barrel nuts.

If you need additional help please start a new post so others can see it and offer help. I try to check here after work but some nights I'm just too tired.
 
#22 ·
Fixed

Thanks to all for help.
The band/hard 1-2 shift is gone. I replaced the piston, honed the accumulator housing and put it back together. Works great. I also got my OD back - it was the manifold pressure switch. I had another thread on that & will post there.
 
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