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So I am attempting my first 4l60e rebuild. Trans is a model year '93.
My low revers piston is damaged
I am wondering what caused this wear and if i should replace it or not.
Reverse is what failed in this unit.
I want to make sure I identify and solve this issue before it goes back together.
Also to note the low revers spring cage was very difficult to remove because the springs were in a state of near coil bind and not easily compressed.
additionally there is a check ball located in the case that used two tabs to retain it. that ball flew right out when I put a magnet near it.
I have done a bunch of research for this but I cant seem to find any info on this.
Where there any other broken parts or things that didn't seem right?
You still had all forward gears? If you had all forward gears, it shouldn't be a broken sun shell. Check the low reverse clutch pack. The frictions might be toast.
The only thing that could potentially touch the low reverse piston in that spot is the rear ring gear, which holds the rear planetary gears. How do your rear planetary gears look? They should have less than ~0.020" play.
Where there any other broken parts or things that didn't seem right?
You still had all forward gears? If you had all forward gears, it shouldn't be a broken sun shell. Check the low reverse clutch pack. The frictions might be toast.
The only thing that could potentially touch the low reverse piston in that spot is the rear ring gear, which holds the rear planetary gears. How do your rear planetary gears look? They should have less than ~0.020" play.
All forward gears were working to my knowledge, and the sun shell was intact but I ordered the TCI "beast" sun shell to be safe. Low revers clutches were completely smoked and located in the pan in sediment form. lol
yeah the wear looks to be from the rear ring gear it has the right angle, So im really confused as to how they made contact. Its really bugging me that i cant figure it out. I have heard there there is an updated low revers spring cage, could using the wrong one possibly cause this issue? And my rear planetary gears have unacceptable wear on the needle bearings so i will be ordering a new one or pulling a spare '98 trans apart to use the one out of that.
Yeah I ordered a TCI master rebuild kit that has all the seal, bushings, clutches and frictions. Doing a pump rebuild. I might even be doing the Teflon shaft seals which im kind of nervous about with out the proper tools.
Awesome! ill give that a read once Im done with class for the day.
Yeah I ordered a TCI master rebuild kit that has all the seal, bushings, clutches and frictions. Doing a pump rebuild. I might even be doing the Teflon shaft seals which im kind of nervous about with out the proper tools.
Awesome! ill give that a read once Im done with class for the day.
You can do the teflon seals yourself with some radiator clamps, a long thin funnel, and some thin flexible plastic like what you'd find in a two liter soda bottle. I used acetate paper instead, but there's a picture and some details in my thread about doing it. It's not difficult but it does have to be done right. A shop would be able to do it for you for minimal cost if you feel unsure about doing it yourself.
I'd also consider letting the shop handle all the bushings. And let them put your case in their parts washer.
For rebuild videos, I'd visit transmissionbench.com for their free, streaming 4l60e videos. They're what I used and there are no better videos on the Internet for a 4l60e rebuild.
Don't forget to check your reverse drum for burning or warping. If you think there's a problem with that spring cage, then replace it. They're cheap. A new separator plate (Transgo makes a great one for $20) is probably a good idea. How'd your old one look with regard to the ***** pounding the plate holes?
All forward gears were working to my knowledge, and the sun shell was intact but I ordered the TCI "beast" sun shell to be safe. Low revers clutches were completely smoked and located in the pan in sediment form. lol
yeah the wear looks to be from the rear ring gear it has the right angle, So im really confused as to how they made contact. Its really bugging me that i cant figure it out. I have heard there there is an updated low revers spring cage, could using the wrong one possibly cause this issue? And my rear planetary gears have unacceptable wear on the needle bearings so i will be ordering a new one or pulling a spare '98 trans apart to use the one out of that.
Relative to my '96 4l60e, I'm not aware of an updated low reverse spring cage. I did replace all of my spring cages and the only one that was updated was the overrun spring cage. See post #34 of my rebuild thread for pictures and clarification. If your kit includes new steel pistons, you will need the updated overrun spring cage, AC Delco part #24206085.
If one needle bearing is bad, I'd consider ordering a new set of needle bearings to replace all of them. It should be about $30. You'll probably spend upwards of $10 when you include shipping if you only buy one.
How's the play on the actual planetary gears? And does your rear ring gear show wear where hit hit the piston? Taking out a chunk like that should've produced a visible mark on the ring gear.
If using used planetary gears and/or ring gears be sure to replace them in sets. If just replacing a used planetary gear or ring gear or even a sun gear you could get noise from the mismatched gear sets. Whenever I install used gears I replace all three.
The '93-'95 models have an issue with the low/reverse clutch not exhausting fast enough. You can do a feed and bleed mod to the piston and remove the check ball from the case or, you can find a '96-up manual valve and drill the valve body casting to improve the exhaust path of lo/reverse clutch oil.
You can do the teflon seals yourself with some radiator clamps, a long thin funnel, and some thin flexible plastic like what you'd find in a two liter soda bottle. I used acetate paper instead, but there's a picture and some details in my thread about doing it. It's not difficult but it does have to be done right. A shop would be able to do it for you for minimal cost if you feel unsure about doing it yourself.
I'd also consider letting the shop handle all the bushings. And let them put your case in their parts washer.
For rebuild videos, I'd visit transmissionbench.com for their free, streaming 4l60e videos. They're what I used and there are no better videos on the Internet for a 4l60e rebuild.
Don't forget to check your reverse drum for burning or warping. If you think there's a problem with that spring cage, then replace it. They're cheap. A new separator plate (Transgo makes a great one for $20) is probably a good idea. How'd your old one look with regard to the ***** pounding the plate holes?
I read your thread, great quality there! I think I'm going to give the shaft seals a shot. you made em look easy so hopefully I can pull it off.
I attempted to clean my case in an industrial parts washer for about five mins tonight before I gave up. That build up is nasty on the out side and I really don't want to nick the valve body surface. I brought my case back from the shop tonight. Hopefully the trans shop down the street has a case washer and will give it a spin for me for cheap money.
I think I am going to try the bushings my self to save some money, but we will see how that goes...
I have actually watched all of those video. They were partly what inspired me to do this.
My drum only showed the smallest light gap when I held up a straight edge and the plate was pretty beat. Ill put an order in for that one unless the trans shop down the street has an oem one cheaper. How do you feel about the rubber *****? Those would prevent the issue but would they hold up?
Relative to my '96 4l60e, I'm not aware of an updated low reverse spring cage. I did replace all of my spring cages and the only one that was updated was the overrun spring cage. See post #34 of my rebuild thread for pictures and clarification. If your kit includes new steel pistons, you will need the updated overrun spring cage, AC Delco part #24206085.
If one needle bearing is bad, I'd consider ordering a new set of needle bearings to replace all of them. It should be about $30. You'll probably spend upwards of $10 when you include shipping if you only buy one.
How's the play on the actual planetary gears? And does your rear ring gear show wear where hit hit the piston? Taking out a chunk like that should've produced a visible mark on the ring gear.
Yeah, sorry about that. I had that wrong, the updated spring cage was the overrun. My kit did not include the new bonded rubber pistons but I ordered them separately. I also ordered that updated spring cage you talked about. But that order is MIA currently.
I have not inspected my needle bearings yet. I was referring to the needle bearings that the planet gears ride on. They can rock back and forth considerably. Also the ring gear shows slight signs of wear but its a hard steel so the piston got brunt of the damage.
Is it possible that the piston was allowed to travel further than normal because so much material was missing from that burnt up clutch pack? That extra distance made interference happen? that still does not explain why the piston was so far up the case basically in full apply. I tried to hit it down and tried to compress it down. It would not budge. Also when I used air to apply the piston it would move but not enough to see; only enough to feel and hear. Maybe I only heard the seals slapping about? Once I mangled out that retaining ring it did not put up that much of a fight coming out.
If using used planetary gears and/or ring gears be sure to replace them in sets. If just replacing a used planetary gear or ring gear or even a sun gear you could get noise from the mismatched gear sets. Whenever I install used gears I replace all three.
Good to know! Ill be sure to grab all three from that other trans.
If those are bad and I am o.k. with a gear wine would just buying one be fine?
Would they break in or are the surfaces already too work hardened?
The '93-'95 models have an issue with the low/reverse clutch not exhausting fast enough. You can do a feed and bleed mod to the piston and remove the check ball from the case or, you can find a '96-up manual valve and drill the valve body casting to improve the exhaust path of lo/reverse clutch oil.
So when you say they do not exhaust fast enough; when the unit is placed in drive the revers clutch is over powered causing wear?
What how would removing that check ball affect the system?
...
I have not inspected my needle bearings yet. I was referring to the needle bearings that the planet gears ride on. They can rock back and forth considerably. Also the ring gear shows slight signs of wear but its a hard steel so the piston got brunt of the damage.
...
The standard sun shell and "The Beast" put a lot of strain on that needle bearing within the planet. This is why Sonnax created their "Smart Shell" which diverts to load to the much strong low/reverse race and its bigger bearings.
Great to see Cory helping you out!
And of course Mr. Bond.
And relatively new member MPTrans (are you a pro builder?)
Removing the checkball prevents the restriction of the exhaust oil from behind the piston, helping it release faster. In '96 the manual valve and valve body casting was changed to help exhaust the oil faster fixing the problem in the '93-'95 units. What happens is that when shifting from reverse to drive the low reverse clutches are dragging as soon as you start moving until they are fully released. This causes the clutches to wear making them thinner or even delaminate causing the piston to travel up higher and make contact with the rear ring gear. Mrvedit, I have been building transmissions for 20 years.
I read your thread, great quality there! I think I'm going to give the shaft seals a shot. you made em look easy so hopefully I can pull it off.
I attempted to clean my case in an industrial parts washer for about five mins tonight before I gave up. That build up is nasty on the out side and I really don't want to nick the valve body surface. I brought my case back from the shop tonight. Hopefully the trans shop down the street has a case washer and will give it a spin for me for cheap money.
I think I am going to try the bushings my self to save some money, but we will see how that goes...
I have actually watched all of those video. They were partly what inspired me to do this.
My drum only showed the smallest light gap when I held up a straight edge and the plate was pretty beat. Ill put an order in for that one unless the trans shop down the street has an oem one cheaper. How do you feel about the rubber *****? Those would prevent the issue but would they hold up?
A
I've never heard anybody say anything negative about the torlon checkballs. Are you referring to them when you say "rubber *****"? Torlon isn't rubber, it's a high temp, high strength plastic and it basically eliminates separator plate wear. I used them in my rebuild. If your plate is in bad shape, it needs to be replaced too.
It wouldn't hurt for you to post a picture of your reverse input drum and let the more experienced folks (not me) on here have a look to see if they'd recommend replacing it.
Last edited by coryforsenate; 04-09-2015 at 12:22 PM.
You said you have a rebuild kit, but I imagine like most rebuild kits it has little or no valve body stuff.
Were you planning to get some valve body stuff? There's two kits that most everybody seems to use, Transgo and Sonnax. I used the Sonnax Performance Pack and really liked the stuff that came in it. Also includes some stuff for the case, pump, etc. Regardless of if you get a valve body kit, I'd replace any plastic accumulator pistons if yours has some.
And don't forget to replace the 3rd accumulator checkball capsule.
Not sure what fluid you had in mind, but the new(ish) Dexron VI AC Delco fluid is pretty cheap and full synthetic base stock, at about $24/gallon. GM says that Dex VI supersedes Dex III and can be used in all transmissions using Dex III fluid.
I don’t believe that the 3rd accumulator checkball capsule needs to changed at every rebuild. If the capsule is not damaged, all that is needed is a good cleaning and test for leaks. A little seepage is okay. Trans builder PBA also says this in this thread post #5. https://ls1tech.com/forums/automatic...-question.html
04-07-2015, 11:53 PM
First time 4l60e Rebuild help 
