4L80E output shaft binding when rotating clockwise

[primetime]

@clinebarger I got one for ya. Well this one is a first, at least for me. Didn't have this issue in previous builds.

2004 late 4L80E case
Sonnax no walk bushing inverted, confirmed roller bearing makes contact with output shaft and that the bushing is not impacting rear end play in any way. Bushing is black side facing the case.

The rear endplay is 0.005"

So stacking it up to the center support and leaving the low roller clutch and reverse band out, with the bellhousing facing the sky, the output shaft rotates both directions. As soon as you tighten the center support bolt to 29 ft /lb (or even 15 ft / lbs) and change nothing else, it becomes very difficult to turn the output clockwise and it gets to a point where the binding is really bad. You have to rotate it counter clock wise 1/4 a turn just to get it to start moving clockwise again. It will rotate with one hand for about a turn and a half, and then bind really bad. This is with beveled snap ring out. Tightening the bolt is essentially centering the center support, so it's an assembly issue or a part issue. If you add a direct drum to the mix, (just the drum itself, no frictions anywhere in the case) it becomes almost impossible to rotate clockwise. Counter clockwise is fine. Rotating it by grabbing the direct drum from the top is fine, rotates in both directions. So back to just the stack up to the cs:

- Sun gear is in correct orientation
- Everything is lubed
- All washers and bushings and bearings in the stack are accounted for an in correct orientation, triple checked
- Bushings in the output, center support, and front planet appear to be straight and at correct depth. About to replace them just to see if it makes a difference.
- Reverse band removed for this testing
- Low roller clutch removed for this testing
- All the parts are the correct year and what originally came in the case
- None of the rear servo or accumulator parts are installed
- Not seeing any wear on the hard parts that would cause this issue

Of course if you remove the sun gear tube, everything rotates easily in both directions. This leads me to believe that perhaps the sun gear tube is warped, or the billet main shaft is warped, or something is up with this case or another hard part causing it to not be on center. The main shaft is new. When I put a calibrated straight edge against the sun tube and main shaft neither appear to be warped. Durabond fluted bushings in the tube were finish in place, as they didn't go on the main shaft easily so they had to be honed. Bushings were pressed in and should be straight. They look straight.

Plan is to get a new sun gear tube on Monday, press in the new bushings and hone if necessary and see if the problem persists. If so, then I'm going to get the main shaft checked to see if it's bent. What am I overlooking here?

 

[primetime]

Well it’s not the sun gear tube.

The entire 2004 assembly stacked to cs goes in a 95 case and doesn’t bind when rotating output clockwise.

Put the 95 assembly in the 2004 case and it doesn’t bind either.

Take the 2004 assembly stacked to cs in the 2004 case and replace the output with the 95, and it’s much better but still not as smooth as the entire 95 assembly in the 2004 case.

I’m going to replace the bushing in the 2004 output and the rear bushing in the 2004 case. I don’t think those are the issues though. Maybe the 2004 ouput is slightly bent but somehow it’s not causing binding in the 95 case, but it is in the 2004 case.

Also I noticed that the 2004 center support has some play in the 2004 case. You can put the bolt half way in, grab the bolt and move it left to right and the cs moves between the lugs. I tried torqueing it down with the cs held left and held right, made no difference. We’re only talking .010 or so play here but maybe the lugs in the case are worn just enough to cause it to perfectly not center causing the clockwise binding.

 

[97K15004WD]

Huh, that is weird.

 

[primetime]

It is weird. I'm aware of all the 95 vs 2004 part differences, but I only have those 2 cases here and wanted to rule out the 04 case as being the issue.

 

[clinebarger]

With the Anti-Fretting ring & Beveled Snap-Rings in place.....The Center Support bolt shouldn't move the Support much at all, Have you tried installing the beveled Snap-Ring, Then torque the Support Bolt?

The Sun Gear Shaft Bushing can be a bear, Though I don't deem honing them to size practical because they're fluted & can be honed off center too easily.
I've machined some installers that do not allow the bushings to shrink to much, Sometimes when I press them in....Material from the OD will get shaved off because the bushing wall thickness was a little too thick. Then I have to press the installer back out.....But it sized the bushing correctly without honing.

How to center the Case Bushing.....
*Stack the original Selectable 3-tang washer & Trust washer like original.
*Install just the Output Shaft.
*Using a long brass drift or a long piece of hardwood & strike the Output near it's outer edges in a star pattern

This will center a cocked bushing.

There are oversized Sonnax No-Walk bushings.....You didn't mistakenly install one did you?

 

[primetime]

So I removed the 34006-SP no walk bushing that was in there and replaced it with a TH400 bushing. I drove it in such that 0.125” was sticking out into the case. Then I put my .030 shim and bearing around it and confirmed that the bushing did not protrude past the bearing. Used Red loctite.

Then I put just an output shaft in the case and used a rubber mallet to tap at it on all sides. Then I pressed in a pair of new fluted bushings and honed them aiming for .0015” clearance. Now everything is playing nicely and the stack rotates clockwise. I put the bolt in before the beveled snap ring as all this was done prior to seeing your post, but know now to put the bolt in last. Something was up the old bushings, but glad it’s working now! Rear endplay is .005” Using the 3 prong oem washer around the bushing would have been better for centering I see prior to tapping it. Seems centered now, but I may do that trick just to be certain. Thanks again!

 

[primetime]

Looks like I spoke too soon. So it's got:

New sun gear tube with bushings
New output shaft bushing
New rear case bushing.

Granted the bushings were already replaced, but I replaced them again.

Stacked to the cs, with intermediate clutches in there and set at .045" with snap ring on int pressure plate it's fine in both directions. Nice and smooth. As soon as you stack the direct drum and forward drum along with their clutch packs, it completely binds and won't move clockwise as these components center the internals even more. Inspected the direct drum and forward and they look fine, but it is a remanufactured forward drum. About to swap it and see if that fixes it. Is it possible to have a bent main shaft? This thing is a 300m billet shaft. Looks to be correct height, no?

 

[primetime]

Took it back down and restacked to pump. New pump bushings are at correct depth and still had to hone these. I wonder if I got fake durabond bushings as these didn’t have part numbers on the bag in the TK-4A kit. Can turn counter with one hand on output, (valve body side facing north) can turn clockwise with 2 hand but it’s tough. I don’t recall it being this hard to turn counter but I’m probably over thinking it. Hollow Billet Main shaft was correct height out of the box, typically have to take .060 off when using in a late case. Doesn’t make contact with top of input. I think we are good.

 

[primetime]

@clinebarger One thing I forgot to ask you about was the setting of the Forward Hub to Direct Drum end-play to .003"-.008" when rollerzing a stock hub. You had mentioned that if you use a sonnax hub billet hub that comes with the bearing, that the end-play there is zero and is correct. So my question is why not machine the stock hub to zero as well when rollerizing a stock forward hub rather than machining it to .003"-.008" worth of play? Can that only be set to zero in cases where a forward clutch hub and bearing combination shifts the support of the forward clutch hub from the main shaft to the direct housing and sun gear shaft? Trying to visualize it.

 

[clinebarger]

The theory behind running zero endplay between the Forward Hub & Direct Drum is to lesson what is known as Direct Drum Float, But using a stock Hub to achieve this can result in too little Front Unit Endplay as you need to physically lift the Hub off the Main Shaft to get zero Hub to Drum endplay.

.003-.008" still reduces Direct Drum Float by quite a bit in most cases. Aftermarket Hubs don't sit on the Main Shaft as the splines are counterbored.......These can cause Front Unit endplay issues in some cases (outside what a factory selectable front thrust washers can account for).

If I want true zero hub to drum.....I machine the Hub down 'til there's @ .001-.003" endplay.........Then run a .005" shim between the Hub & Bearing. This way I KNOW I didn't move the Hub up anymore than .004".

Loading of the bearings in the Rear Unit doesn't matter either way in terms of reliability.

 

[primetime]

Got it! Thanks for taking the time to explain this.

 

[primetime]

I'm not familiar with fixed line pressure setups in terms of tuning. The EPC is removed and the bore is plugged, and will probably see 190 PSI but will log it with a 0-4.5v / 0-300psi transducer to be sure. Its a Sonnax LB1 boost valve and LB1 sleeve with a CK purple spring and stock PR valve.

I'm still on MPV1 HP tuners for now. Is there any setting that must be taken into account when dealing with fixed line pressure in HP tuners? Stall is a 3500, single disk lockup.

If you still have your old tune file with your 4th gen/4L80E in HP tuners I could take a look at it and it would give me an idea if you were on fixed line pressure as well.

It won't let me post the tune link or the tune file on here, so here is the image of the link which contains the tune file I was working on. It's 4L60E to 4L80E segment swap, but takes into account the tune parameters that was already on the car for the 4L60E on the engine side.

 

[clinebarger]

I'm not running anywhere near enough power for a fixed line pressure unit, Without a EPC the only tuning is the shift points & TCC on/off.

The best tip I can give is.....Transmissions are Hydraulic....Just because you set a shift point to a certain RPM/MPH doesn't mean a shift will happen right at that point, It's just when the shift solenoid/s will be turned On/Off.

 

[primetime]

Ok I wasn't sure if there was more to it. I've got my initial shift points set and TCC apply/release tables set. Aren't certain D3 transbrakes fixed line pressure regardless of the power as they have you disconnect the EPC, some grinding the middle land or blocking the EPC completely with a plug?

 

[clinebarger]

Ok I wasn't sure if there was more to it. I've got my initial shift points set and TCC apply/release tables set. Aren't certain D3 transbrakes fixed line pressure regardless of the power as they have you disconnect the EPC, some grinding the middle land or blocking the EPC completely with a plug?

That is correct, But has nothing to do with tuning other than disabling the EPC electrical DTC's. Grinding the middle land & blocking the reverse feed to the Boost Valve is so there's no Reverse Boost which can easily cause runaway line pressure.

 

[primetime]

That is correct, But has nothing to do with tuning other than disabling the EPC electrical DTC's. Grinding the middle land & blocking the reverse feed to the Boost Valve is so there's no Reverse Boost which can easily cause runaway line pressure.

Yeah jake said the EPC block off plug works better so I ordered the plug instead after grinding on a brand new EPC per his D3 instructions.

Also I just stroked the TCC valve in the pump and the **** coiled pin falls right out as soon as you move the valve. That’s a new discovery for me. Assuming the TCC hitting the pin wore it out. New pin on order GM 8661838.