Diff rebuild by "pro" not going well

Piratetip

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Dec 30, 2005
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Looks good.
Nice find on the pinion imperfection and polish.

You should be good to run it now.

I hope it's the last time you have to tear this down!

Pinion pattern looks good, not tailing much at all to the center, a mark of good depth not too deep.
 
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alcyon

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Jun 15, 2017
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Ok update. I pmed Piratetip yesterday that that knock is back on reverse, but its very faint. So this morning I finally tested the car. I am glad to report that the diff is as close to perfect as possible, its like 97% there. Hardly any whine in accel and decel, and very faint "knock" at very very low speed decel. I think no one else will notice. I can finally listen to music while driving. I drove all the way to my office gently accelerating and decelerating and it was all smooth.
I am just so glad to wrap this up finally, what more , I would be flying to Italy in a few hours. Special thanks to PirateTip and the guys in Gear Technical Install group on facebook.
 
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Piratetip

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I've just returned to the country, have been out for awhile.
I will give a read when I have some free time.
 
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Piratetip

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Sounds like you got it working.
Has it quiet down any more now with more miles on it?

Glad you persevered and figured it out.

Still strange the ring had damage new out of the box, i have never encountered that before.
You managed to work through a lot of problems, nice job
 

alcyon

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Jun 15, 2017
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Sounds like you got it working.
Has it quiet down any more now with more miles on it?

Glad you persevered and figured it out.

Still strange the ring had damage new out of the box, i have never encountered that before.
You managed to work through a lot of problems, nice job
I havent got the chance to put more miles on it, so far I have only gone about 80km on that Sunday itself. I am still in Italy and will only be back on the 25th. I plan to fill up a tank full and drive till i finish that tank before swapping out to AMSOIL synthetic fluid.
 

alcyon

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Jun 15, 2017
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Any updates?
Ok I am back and drove the car for roughly 2 days for some short trips. Noticed a few things. Overall everything is stiil good. Noise isnt getting worse. I do notice some hum on slow decel (30kmh and less), and some hum on hard accel. Since I am still in the break in period and only put about 280km on the diff, I still got about 400 to 450km to go before I end break in and change diff oil. Have not really got the chance to hammer on the diff, I did accelerate a bit hard off turbo boost and it seems silent enough, however on some load going uphill I do hear some light hum, but then again nothing alarming like before.
Have not went beyond 90kmh yet.
 

alcyon

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Jun 15, 2017
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More Updates
There is a hum from 80 to 90kmh, but goes away over that speed, I went to 105kmh for a few seconds and its very quiet at that speed.
For the most part, coasting decel is also quiet. There is some whine-hum when throttle is transitioning between accel and decel, when the ring and pinion "floats", but since this condition happens for a short period of time, I feel its nothing to worry about.
 

alcyon

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Jun 15, 2017
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Kuala Lumpur
Ok an update. I think everyone know about my propeller shaft rebuild. I just removed it and in the process I rechecked my pinion preload.
It seems to still have preload but I also noticed that it has lost a little preload.
There is a very slight hum especially when the diff "floats", meaning when the gears are not under load, like when I am coasting downhill but I still give it very light throttle, its like the ring and pinion is under minimum load if you get what I mean. When I let go of the throttle and just let it coast there is hardly any sound. On hard acceleration, also hardly any sound. So I was wondering, should I replace this nut and just crank down on a new nut (I have a spare nut) just to get the preload tight again. I shouldn't have to worry about overtightening as there is no crush sleeve in here.
Its just difficult to tighten this nut under the car, even with my companion flange tool. I plan to rest the tool rod on the floor and tighten the center nut, but I have a feeling I would be lifting the whole chassis up a little as I crank hard on the nut.

Also I have another question. I re read the TSRM, and according to the wording
"Using a torque wrench measure the preload of the backlash between the drive pinion and ring gear"
Doesn't this mean the break away torque ?
If that is the case then I probably have the pinion preload a bit too high ?
1675046936696.png
Also notice the illustration shows him checking the torque under the car, meaning it cannot be a constant turning torque.

Another post by turbostreetcar:
1675048841649.png
 
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