Humming noise after SYE

Phil said:

Driveline angles. Measured driveline angles. With a measuring tool.

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Just did. I came up with 1 degree. It was about 11 on the driveshaft and 10 across the yoke.

And that’s with a 2 degree shim in place

RCP Phx said:

You can measure the pinion angle off the 2 manufacturing boss's on the back of the diff housing, you can measure the TC output off the engine valve cover.

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Needs to match the driveshaft for a CV type driveshaft. Measure on the tube itself in this case.

Rockwood said:

Needs to match the driveshaft for a CV type driveshaft. Measure on the tube itself in this case.

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I did, if you missed my above post I came up with about 1 degree. I believe I am doing this properly? Measure the driveshaft on the tube. Remove it, measure across the yoke.

UPDATE
Let me recap what’s going on. It’s a faint rumble sound. I had some vibrations prior to getting the SYE. This is different. I noticed it right away after picking it up from the shop after having an SYE kit installed. It’s throttle dependent and will go away when you take your foot off the gas. It’s constant at all speeds. Doesn’t change pitch when the trans changes gears.
It’s lifted about 2 1/2 inches maybe closer to 3 in the rear. HD leaf from general spring and a JKS boomerang shackle. I figured it was pinion angle like everyone usually says so I added a 2 degree shim. I re measured my pinion angle today and I am pretty much at 0. 11 degrees across the DS tube and 10 degrees across the yoke with the DS removed. Adding the shim didn’t change anything sound wise.
Today I pulled the front DS and took a drive and nothing changed. I pulled the rear and drove in front wheel drive (4hi) and the sound went away. I tried putting my front driveshaft in the rear and the sound returned. So it’s not the new DS. I thought maybe it could be related to the differential? I opened it up and had a look and to my untrained eye everything seemed ok. No wear or missing teeth. Oil seemed good. The gears are fairly new too.
I’m at a loss, any advice on what else to check would be much appreciated.

steventure said:

I did, if you missed my above post I came up with about 1 degree. I believe I am doing this properly? Measure the driveshaft on the tube. Remove it, measure across the yoke.

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Ah, yeah. Perfect.

I had a rumble noise from my transfer case resting on my skid plate, went away under throttle, came back coasting. Could be something on the passenger side of the engine/exhaust contacting something else.

Rockwood said:

Ah, yeah. Perfect.

I had a rumble noise from my transfer case resting on my skid plate, went away under throttle, came back coasting. Could be something on the passenger side of the engine/exhaust contacting something else.

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Mine is only under throttle. Goes away as soon as you take your foot off the gas. Gets more harsh when you really get on it, step on the gas.

Did you get a new tcase chain when you had the SYE done? I had something similar when I did my SYE and chain, without changing the sprockets. I had the sound on acceleration only as well.


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DocTremp said:

Did you get a new tcase chain when you had the SYE done? I had something similar when I did my SYE and chain, without changing the sprockets. I had the sound on acceleration only as well.


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No I don’t believe so. I’m taking it back to them Tuesday and having them open it back up. I wanted to exhaust all areas first and confirm whwre it’s coming from. 90% certain it’s related to the Tcase now. Thank you I’ll run that by them and make sure they check

Give them hell for not test driving it after working on the tcase.

steventure said:

Mine is only under throttle. Goes away as soon as you take your foot off the gas. Gets more harsh when you really get on it, step on the gas.

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Yeah, that's why I said I'd check for something rubbing on the passenger side of the drivetrain since that's the way the motor tilts under load. Decel (my problem) is the driver's side.

How are your motor mounts and transmission mount? Relating to the drivetrain shifting under load and letting things run together.

Phil said:

How are your motor mounts and transmission mount? Relating to the drivetrain shifting under load and letting things run together.

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Mine? SFR and Brown Dog mounts. Based on the rattling interior panels at idle, I'd say fine. Skid plate is close for max clearance is all. Shimmed the mounts up a little to clear the skid.