Suddenly lost 4th gear 4L80E
04-28-2014, 05:53 PM
#22
I've checked resistance, both solenoids are around 20 Ohm, so I assume they are good.
I've tried to move 3-4 valve as well as 2 valves on top of solenoids A and B, they all move freely.
Is there anything else to check?..
P.S. When I removed VB, I can only see 4 ***** in the case (green) circles, and another 5 empty spots for ***** (red circles), is that OK? Also rubber gasket is a bit damaged (yellow circle) over what appears to be small inner torx bolt, is that an issue?
help!..
I've tried to move 3-4 valve as well as 2 valves on top of solenoids A and B, they all move freely.
Is there anything else to check?..
P.S. When I removed VB, I can only see 4 ***** in the case (green) circles, and another 5 empty spots for ***** (red circles), is that OK? Also rubber gasket is a bit damaged (yellow circle) over what appears to be small inner torx bolt, is that an issue?
help!..
04-29-2014, 11:19 PM
#24
Do the clutches look black? You can see them somewhat while the pan is off, you'll be able to get a good look once you pull the pump and OD assy.
The 4 checkball locations you noted are correct.
04-30-2014, 01:54 AM
#25
I hope that bolt is correct, I can't see what's the purpose of it, except slightly restricting flow? it doesn't block or switch something the way I see it...
Clutches look somewhat bronze?? if I'm looking in the right direction. They shouldn't be cooked since I only got into 4th gear under WOT for a few times.
While removing pump and OD assy, am I looking for something obviously broken?
P.S. I remember I had changed 3rd<->4th while TC was locked once or twice, could that rip off the clutches?
Clutches look somewhat bronze?? if I'm looking in the right direction. They shouldn't be cooked since I only got into 4th gear under WOT for a few times.
While removing pump and OD assy, am I looking for something obviously broken?
P.S. I remember I had changed 3rd<->4th while TC was locked once or twice, could that rip off the clutches?
05-01-2014, 09:43 AM
#29
Anyways, where is that piston, do I get there from the front where the pump is?
I will be reading a lot now on disassembling 4L80E, and I don't expect that here on forum I will be taught step by step how to get to OD clutches, but still, any hints will be helpful )
05-01-2014, 12:01 PM
#30
Don't think it's just a leak in a seal, air was going there completely unrestricted.
Anyways, where is that piston, do I get there from the front where the pump is?
I will be reading a lot now on disassembling 4L80E, and I don't expect that here on forum I will be taught step by step how to get to OD clutches, but still, any hints will be helpful )
Anyways, where is that piston, do I get there from the front where the pump is?
I will be reading a lot now on disassembling 4L80E, and I don't expect that here on forum I will be taught step by step how to get to OD clutches, but still, any hints will be helpful )
You REALLY need a manual to tackle it.
Pull the pump, remove the OD assembly, remove the T40 bolt, and lift the OD housing out of the case.
Jake
05-01-2014, 01:31 PM
#31
Shocking thought... This inner-torx bolt on my last picture wasn't secured at all, I just pulled it out with my fingers. That's why I wrote I don't understand the purpose of it. Should this bolt really HOLD something (like 4th clutch case)?
Could I have just ripped away 4th clutch housing, thus this bolt is just sitting there free???
Could I have just ripped away 4th clutch housing, thus this bolt is just sitting there free???
05-01-2014, 11:15 PM
#34
The bolt serves a purpose. It's there to fasten into the OD basket to prevent it from rotating. It's hollow to allow fluid to pass through to engage the piston when needed. If you remove the bolt completely, and pull the pump and the input shaft/OD planetary assembly, you will see the basket sitting there in the case. Wedge a flat head screw driver behind the pump and use the leverage to get the pump out, very easy.
When the basket is sitting there, you will be able to see how it can rotate a little bit. There is a tab that rests in a case indentation that restricts the movement somewhat, but the bolt is there to keep is perfectly stationary and not prevent blockage of the passage.
Air should not have been going in unrestricted, you should have been able to clearly hear the sound of clutches applying. Pull the pump and input assembly out and check for black clutches like Jake said. Don't disassemble the OD basket or remove any clutches yet, but take the basket out and blow air directly into the basket hole. You should see a definite clear movement of the piston applying the clutches. If not, then a seal is blown and needs to be replaced.
Unfortuntely, that specific assembly in the transmission requires a specialty tool so you'll probably have to take it to a shop to have it fixed, this is one of the few things you can't really improvise at home and fix, nor would I recommend trying to.
Make sense?
When the basket is sitting there, you will be able to see how it can rotate a little bit. There is a tab that rests in a case indentation that restricts the movement somewhat, but the bolt is there to keep is perfectly stationary and not prevent blockage of the passage.
Air should not have been going in unrestricted, you should have been able to clearly hear the sound of clutches applying. Pull the pump and input assembly out and check for black clutches like Jake said. Don't disassemble the OD basket or remove any clutches yet, but take the basket out and blow air directly into the basket hole. You should see a definite clear movement of the piston applying the clutches. If not, then a seal is blown and needs to be replaced.
Unfortuntely, that specific assembly in the transmission requires a specialty tool so you'll probably have to take it to a shop to have it fixed, this is one of the few things you can't really improvise at home and fix, nor would I recommend trying to.
Make sense?
05-02-2014, 04:02 AM
#35
Yes it makes, thank you!
Couple specific questions I'm not clear yet:
1) do I remove center support bolt (12pt), front and rear servos, and parking stuff to remove pump and OD assembly?
2) I was reading that you have to remove some rubber o-ring from input shaft to be able to remove the pump, where is that o-ring?
Couple specific questions I'm not clear yet:
1) do I remove center support bolt (12pt), front and rear servos, and parking stuff to remove pump and OD assembly?
2) I was reading that you have to remove some rubber o-ring from input shaft to be able to remove the pump, where is that o-ring?
05-02-2014, 04:29 AM
#36
Yes it makes, thank you!
Couple specific questions I'm not clear yet:
1) do I remove center support bolt (12pt), front and rear servos, and parking stuff to remove pump and OD assembly?
2) I was reading that you have to remove some rubber o-ring from input shaft to be able to remove the pump, where is that o-ring?
Couple specific questions I'm not clear yet:
1) do I remove center support bolt (12pt), front and rear servos, and parking stuff to remove pump and OD assembly?
2) I was reading that you have to remove some rubber o-ring from input shaft to be able to remove the pump, where is that o-ring?
2) Yes, it's right there on the front of the input shaft, you can't miss it. A new one is normally green but it may be black for you, I'm not sure. Just look between the tip of the input shaft and before the pump stator, like I said, it'll be right there.
05-04-2014, 07:01 PM
#37
OK FINALLY things start to get clear. Indeed T40 bolt holding 4th clutches housing was sheared off.
What's worse though, I found some aluminium piece jammed between case and 4th housing.
There is some damage (scratches) on the 4th clutches housing, something was hitting the housing (or housing hitting something if it did rotate).
Is it serious or not, what do you think?
Also on the 3rd pic I don't know if it's damage from OD housing on the tranny case, or is it fine (area in red)?
On the last 2 pics - sheared bolt and some piece of aluminium I found jammed between case and basket - where does it come from??? What else is broken in my tranny??
What's worse though, I found some aluminium piece jammed between case and 4th housing.
There is some damage (scratches) on the 4th clutches housing, something was hitting the housing (or housing hitting something if it did rotate).
Is it serious or not, what do you think?
Also on the 3rd pic I don't know if it's damage from OD housing on the tranny case, or is it fine (area in red)?
On the last 2 pics - sheared bolt and some piece of aluminium I found jammed between case and basket - where does it come from??? What else is broken in my tranny??
05-04-2014, 07:21 PM
#38
Looks like the pressure plate broke, causing the bolt to break, and the housing spun in the case.
If the threads are OK in the housing, a new pressure plate, clutches, seals, and bolt (and misc gaskets) may fix it.
If the threads are OK in the housing, a new pressure plate, clutches, seals, and bolt (and misc gaskets) may fix it.
05-04-2014, 11:21 PM
#40
A "pressure plate" is the common term used for the end plate used to hold the clutch pack in place. The clutch is applied by the piston, and pressure from the pack is held by the "pressure plate".
I don't know what the specific verbage used by the manual you are using calls it. I haven't used a manual to build a 4L80E in quite a few years.
The iron piece that is broken off, came off the pressure plate. It is a "tang" that fits into the OD housing and then also the case to keep things from spinning and putting pressure on the bolt (that is broken).
Look at the parts closer and you will see the cause and effect.