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clunk!

That doesn't sound right. It's a ferd exaggerated hypoid rear, so by design it may be louder than a corporate. It almost sounds resonant, or hollow, like it doesn't have fluid in it or tolerances are out of spec. Did you notice it getting hot? Maybe check fluid level and run it, then check heat. You should be able to rest your hand on the rear bubble for a few seconds. If you can't, you need to get a infra red gun and post the temp.
 
cheveslakr said:
That doesn't sound right. It's a ferd exaggerated hypoid rear, so by design it may be louder than a corporate. It almost sounds resonant, or hollow, like it doesn't have fluid in it or tolerances are out of spec. Did you notice it getting hot? Maybe check fluid level and run it, then check heat. You should be able to rest your hand on the rear bubble for a few seconds. If you can't, you need to get a infra red gun and post the temp.
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I just filled it when it was new not long before the LS swap but I will check it again. I know it’s not leaking :)

I am going to see what QP says hopefully they reply tomorrow but I will take a cruise and see the heat, I don’t have a heat gun though
 
I had an 84 Ford 1/2 ton van with a worn (Salt Water got inside) rear end and it would Clunk on Acceleration and Decel and also made a Clunk in the air twisting the DS, I got a Pick & Pull rear end when they had an All You Can Carry $$ thing and the Clunk was gone
 
I just took a drive. Got back home and the pumpkin is hot but I can keep my hand on it so not that hot.....Will wait to hear from QP. Also, it is not anything constant, it is really if there is no preload on the rear and and I coasting and then I stab it, clunk. But on normal shifts it seems fine. I do however sometimes get a clunk after I start it and put in in reverse...
 
Just got off the phone with quick performance. They said the videos look and sound normal for an Eaton tru trac…
 
overpaid said:
I just took a drive. Got back home and the pumpkin is hot but I can keep my hand on it so not that hot.....Will wait to hear from QP. Also, it is not anything constant, it is really if there is no preload on the rear and and I coasting and then I stab it, clunk. But on normal shifts it seems fine. I do however sometimes get a clunk after I start it and put in in reverse...
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You didn't put synthetic oil in it ? A helical posi needs standard type oil.
 
The gears in a helical posi need a small amount of friction to work correctly.
If you use synthetic oil, it slips too much and will behave erratically.
I have a Strange S60 with helical posi and I used Lucas 85W-140
 
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Alright well I will drain and fill some non synthetic hopefully there is no damage. I did not see any tags or warnings on the unit when I got it to use regular though
 
overpaid said:
Alright well I will drain and fill some non synthetic hopefully there is no damage. I did not see any tags or warnings on the unit when I got it to use regular though
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The rear ends come with different posi units. The helical posis from Strange Engineering have this note :

Gear Lube
DO NOT USE SYNTHETIC GEAR OIL
Will adversely affect unit operation and void warranty
Use Only Petroleum Based 85W-140 Gear Oil

Here is what they recommended :
https://lucasoil.com/products/gear-oil/gear-oil/lucas-heavy-duty-85w-140-gear-oil

www.strangeengineering.net

Strange S-Trac Differential Fits Dana 60 With 35 Spline Axles - 3 Series - Strange Engineering

Strange S-Trac Differential Fits Dana 60 With 35 Spline Axles - 3 Series - Strange Engineering
www.strangeengineering.net www.strangeengineering.net
 
Good info thanks for sharing. If QP told me not to use synthetic I’m sure I did. If there were no notes or warnings I probably did. Anyway thanks again and I will drain it tonight
 
This is from Eaton’s website:

  • Synthetic oils are not recommended for Truetrac applications. While some customers have found that synthetic oils works well in this application, Eaton has not confirmed under test conditions that all synthetic oils are compatible with Detroit Truetrac applications.
 
Alright, drained, filled...drove around for a while. Drained....filled....I think that is about all I can do.
 
That setup you have looks pretty HD to me so I don't think you will break anything. The noise you hear back and forth in your video is normal driveline clunk. The GM trucks did that and people were scared of driving the trucks. If you are really conserved about it, pull the center section and re-check the backlash and maybe tighten it up a touch. Easy to do on a 9" ferd rear axle assy.
 
cage2592 said:
Maybe tomorrow Ill go out to the shop and look at the 'play' in mine as I do not have this sound.
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Sounds good thanks, I think I have a tru trac in my mustang I have to check the paperwork, it has been a while but I never remember that or a clunk. Problem is even if my mustang behaves differently and yours acts the same, I call QP and they probably won't have much to so or be able to do anything...They are super cool dudes but yea not sure....oh well.
 
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