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TruTrac Install in a 1031 axle

volvoracer82 said:
they don't "count" the teeth, it's a frequency reading, the faster the pulse the sensor sees from the ring determines the speedo needle position.
Click to expand...

A change in gaps/teeth/yadda per rev will indeed change the speed indicated. But as stated, it's working fine. I don't care why it isn't 2% off, it is what it is.
The ABS would indeed hate a missing tooth.

I can clean up the thread if bneeded.
 
Not too worried about it Mike, there's some decent info in the banter. Couple posts maybe but I'll leave it to you if you feel like it and are bored. ;)
 
mikep said:
A change in gaps/teeth/yadda per rev will indeed change the speed indicated. But as stated, it's working fine. I don't care why it isn't 2% off, it is what it is.
The ABS would indeed hate a missing tooth.

I can clean up the thread if bneeded.
Click to expand...

Agreed that 2% is nothing to really worry about, but on 12 tooth variants, the error goes up substantially (8%). I wasn't trying to troll or muddy up the thread, just trying to dispel some misinformation. I certainly wouldn't be the least bit but hurt if some of my posts got deleted. However, I do think it would be an excellent addition to the original post to mention that the speedometer error is:

(n+1)/n - 1

and the speedometer reading, after modification is actually:

(n+1)/n*[actual speed]

Where n = number of teeth, if you add a tooth.

745 TurboGreasel said:
I think the obvious solution is if you have a 12 tooth ring, adding an extra 5/16 gap at one tooth is going to matter a whole lot less, especially because you don't have ABS for it to confuse.
Click to expand...

Agreed, but a new tone ring would be the proper solution. It is possible that the extra gap would cause excessive noise in the signal resulting in needle bouncing.

I'm more than happy to make a group buy happen for water jetted tone rings, if the demand is there.

audeo03 said:
Why the polar bro? Isn't the reading a simple linear rate of what passes the sensor? Such that the extra tooth is changing the frequency as Lando has stated (omega constant, divisions increased)... The sensor doesn't care that the tone ring is rotating or translating.
Click to expand...

omega is a variable for rotational velocity used in polar/cylindrical coordinates.
 
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not sure if things have changed, but the 89449 bearing is the wrong size for the -588 sitting in the shop right now. (not to mention it's huge in comparison to the volvo bearing on the g80)
Race is also way off the correct size, 1031 diff stuff. We're talking off by a couple mm, I have an oem "diff kit" that I shelved years ago, those bearings (Which are the same as the ones on the g80) appear to be the correct size, but not as tall as the 449's.

so.... thoughts or suggestions?

(and yes, I know what summit says about them, they are sitting in the shop right now. not even barry white is going to get those things to match up)
 
gsellstr said:
New pinion nut spec’d for the Volvo axle (the Dana 30 nut is not the right size) [...]
Click to expand...
Is the pinion nut pitch 3/4 x 16 ? Only want to do this once and I think I'm only finding the "Standard" Dana 30 stuff if there is indeed a difference. Had to crank on the original pretty good to get it out so reusing it is out of the question.
 
I thought so, too. For brevity's sake I can't take the old one or the pinion itself and try to fit it up against anything, so that is also out(It'd be special order anyway, most of the locals only have stuff up to 1/2"). The Ratech 321K Install kit lists Component 1500; The catalog then lists two separate nuts. Awesome.

http://www.ratechmfg.com/pop_up_order 1500.htm

Thanks though, I'll dig around a bit more.
 
one thing I did that made life a bit easier, was press the bearings off the old diff and then hone (well, I used my porting tool and an 80 grit sand roll) out the inner part of the old bearings to make a set of test bearings to set the shimming up. ymmv, but in this case, it saved a bit of effort.
 
I installed the TT in my 87 wagon today thanks to information on this thread and Dave Barton's Volvo rear end page. Install went relatively smoothly. Carrier bearing preload was a wee bit tighter than the factory diff and the backlash was right at .006". My only concern was after having the axle on the bench and all set up, I could not get the axle shafts to spin in opposite directions. I used a pry bar on the shafts and they would not budge. The axle felt 100% locked which was not what I was under the impression how this unit operates. Especially when compared to my '77 Scout which I installed a TT in the rear years ago, you lift the tires of the ground and spin one, the other spins in the opposite direction....

I contacted Eaton and they informed me this unit's 'high preload' will result in the symptoms I was experiencing. They blindly said to install the axle in the car and apply some real torque with the driveshaft. So I did and the unit performs as I expected and is a very predictable limited slip. After 40 miles of driving, I came back and lifted one rear tire while securing the rest of the car. The engine struggled but eventually spun the air born tire. It made an awful screeching sound but I still am wondering about the setup on this unit. Anyone else have issues with their TT's being this 'tight'? Eaton also said they will break in over time....

Also this is a 12 tooth tone ring car, I used a G80 ring and cut 36 teeth out. I welded it on after cutting the ring to get it to fit. The speedo was dead on with how it was on the factory diff. Shimmed the pickup with a washer for clearance and it was good to go. Just for info for the 12 tooth tone ring cars.

<a href="http://s1136.photobucket.com/user/williamparrott/media/thumbnail%201.jpg.html" target="_blank"><img src="http://i1136.photobucket.com/albums/n481/williamparrott/thumbnail%201.jpg" border="0" alt=" photo thumbnail 1.jpg"/></a>
<a href="http://s1136.photobucket.com/user/williamparrott/media/thumbnail.jpg.html" target="_blank"><img src="http://i1136.photobucket.com/albums/n481/williamparrott/thumbnail.jpg" border="0" alt=" photo thumbnail.jpg"/></a>
<a href="http://s1136.photobucket.com/user/williamparrott/media/thumbnail%202.jpg.html" target="_blank"><img src="http://i1136.photobucket.com/albums/n481/williamparrott/thumbnail%202.jpg" border="0" alt=" photo thumbnail 2.jpg"/></a>
 
did you install new bearings? i have a complete revision on my axle and now all the plays and preloads dont line up anymore.. :(
 
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