front diff 4x4 options

BeerCan

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I am far from a 4x4 expert.
My growler makes a terrible noise @ 45+ mph. Sounds like rocks in the front diff. Front diff is ford 8.8 with eaton truetrac 4.10 gears

I changed the fluid, or more correctly added fluid because I think it was near empty and no change.
If I put the transfer case in 4x4 high the noise goes away for the most part but I can hear it engage and dis engage ~ 45mph. Obviously I don't want to drive 4x4 H on the street all the time so that is not a good solution.

I removed the driveshaft for now and I will get it balanced. However we all know that is probably not the problem.

I want to bring it to a shop and have something put in something that will work as intended. If that means removing the trutrac and replacing it with something else I am fine with that. I just don't know what to look at and/or ask for. growler has an on board air system.

If I could I would like to get a consensus here from you guys as to the best system to put in the growler. I want to be able to drive it on the street at speed most of the time but I also want a working 4x4 system so I can take it off road and whatnot.

Ideas?
 
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It is one of these?



They have their own forum...might get better responses there...
 

BeerCan

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What's a growler?

It is one of these?



They have their own forum...might get better responses there...
Yes. I have a post over there as well. I'm looking for a solution, doesn't have to be military and I know lot's of people here have excellent knowledge. The whole system is COTS. 8.8 ford diffs front and rear, new process transfer case and GM tranny.

If the front end is a limited slip diff, they get noisy if lubed with stuff rated only for open diffs
It's a eaton truetrac, it specifically calls for un-aditized non synthetic lube, which is what I put in.
 
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MolaKule

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It's a eaton truetrac, it specifically calls for un-aditized non synthetic lube, which is what I put in.
I have never heard of any modern differential requiring an "un-additized" gear lube.

Most differentials now require a GL-5 gear lube which has EP additives.

A low oil level can't help either. Does it have a gasket leak?

@Greasymechtech has a good suggestion about removing the cover to see if any damage has occurred.
 

BeerCan

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I have never heard of any modern differential requiring an "un-additized" gear lube.

Most differentials now require a GL-5 gear lube which has EP additives.

A low oil level can't help either. Does it have a gasket leak?

@Greasymechtech has a good suggestion about removing the cover to see if any damage has occurred.
Poor word choice on my part. I really meant no limited slip additives.
 

BeerCan

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8.8" Ford front sounds Independent?....Does it have Vacuum Actuated IWE's? Those can make noise/have problems.
No vacuum lines I can see. Nothing seems to connect to the diff except the input shaft and axles.

Can someone help me understand how this system works? I'm used to the setup on my Fords with the locking hubs.

this system has no locking hubs, it has front and rear shafts going to the diffs. It has a NP241OR transfer case similar to the one used in the Jeep Rubicon. it has eaton trutrac in both diffs.

In 2H everything seems normal until you get to ~45mph and then you get a noise that sounds like rocks tumbling in the diff (best I can describe it)
In 4H the noise goes away but ~45mph you can hear something that sounds like it is disengaging and when you slow you hear it re engage.

I took the front driveshaft out and the noise is gone.

I would like to know what the noise is in 4h that sounds like it is dis and re engaging?
I would also like opinions on what the noise might be in 2h at 45mph. I know this is near impossible to pinpoint and I can't get a good soundfile of the noise because of all the ambient sounds drown it out.

Someone on the growler forum suggested that the chain in the transfer case is slapping. I can spin the output yoke with the drive shaft off and it sounds smooth but obviously I can't spin it that fast.

Is it ok to put it in 4h without the front driveshaft to see if the noise is present? I don't want to torch the transfer case by doing something stupid.

Any other diagnostic thing that I can do?
 
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Disengaging/reengaging feeling is the lash in your truetracs. Could also be grossly worn out cv's and simply slack from all the components just adding up.

When in 2H, you're not putting any load onto the front diff. Its just dragging along along with the half-shafts' cv's... Something is worn out and doesn't like dragging along.

Without knowing how this vehicle was abused by our fine enlisted teenagers, I'd consider a complete rebuild of the drivetrain. Time for all new bearings, chain, ujoints, cv's.... Consider even getting the vehicle up on a frame machine to make sure its straight and true.

If the front diff was low on fluid, I'd worry about all sumps and any damage that occurred from fluid levels not checked over its lifetime.

Seeing these at the auctions ... thought it was cool, then researched all the issues it comes with.

Put it on a trailer, take it to an offroad park/trail, put it in 4lo and see how far it goes without breaking something.
 
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