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DANA35 IFS SLA preload

wollimann

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Hi at all!

I am on the way to overhaul my 97 front axle. Everything's fine, get new Timken bearings and races, seals, shims, crush sleeve, nut.
Ring/Pinion/Spiders are in good conditions and I have the specs for the dana35, accept the preload for the differential bearings.

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The outer left/right Torrington bearings for the shafts i could not find,
did someone has a hint?

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As I have found out you need a case spreader for this kind of work.
This tool is for widing the case a little bit (x.xxxinch?) to put a 0.001 shim
on both sides to get a little preload?

The differential drive pattern are nearby i think?

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kind regards

Wolfgang
 
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imp

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Your geartooth contact patterns are acceptable. The work can be accomplished by prying the differential carrier out of the housing using a crow-bar, and carefully driving it back in using a rubber hammer, without a case spreader.

Given your patterns, we need to know the conditions under which they were found:

Pinion gear bearing preload?

Diff. bearing preload, as you asked is less easy. But, less important than pinion. 0.002-0.008 inch preload will get you good results. Very difficult to "gauge", measure, without proper tools. If you have a vernier caliper big enough, measure the inside dimension within the center section, then carefully measure the dimension across the differential bearings with outside races held tightly against the bearings. Those two measurements will give you information about the bearing clearance/preload. If preload (interference) is near zero, and good tooth contact pattern was present, add EQUAL shims behind both diff. bearings, to obtain recommended preload, drive the assembly into the housing, snug up bearing cap bolts, check backlash, tooth pattern. If good, wrap a rag around the driveshaft yoke, then with pressure holding the pinion from turning easily, rotate the ring gear/diff. assembly back and forth. Do this with light lubrication on gear teeth. If ANY feel of scraping or non-smooth friction is felt, the gearset will likely make noise. If smoothness is felt, button it up, and yer ready to roll!

This is not an easy process, especially if the proper tools for set-up are not available. But, I've done it, successfully, many times without them. Ya gotta understand what's going on, and what the end result should be. imp
 
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wollimann

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hello,

thank you for your fast answer. This Dana comes from a yunk yard, didn't know anything about it, but it was cheap.
So after opening the oil was very black with little metal&alu pieces in there.
These pieces you found everywhere in bearings and races.
Sealing rings worn and broken.
The shims were located between the bearing / pinion head and bearings / diff.
While I was pulling the bearings the shims were distroyed.
So I decide to put the new shims between races and diff-body.
Thought that I have the possibility to vary with the pinion high (grinded the outer diameter of the used inner race for testing).
But now the problem accure, that I can't get the very thin shims (between diff races and body) driven in. So I think a case spreader is badly needed to add some extra preload shims.

The pinion preload specs I have and yes it is very important for new or used bearings. But for the preload of the diff bearings I am pretty unsure, can't find anything in manuals. If this preload is really recommended and a case spreader ist badly needed, than i would weld a spreader.

As you say, not an easy process, especially if the proper tools for set-up are not available. To this point I am very happy that the pattern are nearly acceptable, some game of patience but I will try to optimize this (especially the drive pattern, think it is impossible to get 100% for both sides).

thanks

Wolfgang


Pulling out the diff, it was very strong in there.
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Metal pieces everywhere
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worn races and no smooth bearings
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SWIGIN

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I have done at least 20 rears in my garage and I can tell you that carrier preload is more of a feel then a measurement.

It's hard to tell over the internet to a beginner what feels right but I use a dead blow hammer/mallet to set the carrier back into the housing and if it falls in with a few taps it is too loose.

If it takes several decent whacks to get it home then your go to go.

Remember that your new bearings will ware as they break in and the carrier will loosen up in the housing so with new bearings you want to have it fight you to a degree to get it in.
 
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wollimann

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Yes your right, the feeling for this stuff -> untill now I didn't get it very well!
And a beginner I am too, but no bloody one. Theoretics I get them, only the experience is missing. I am 53 years old and I will try to held my Ex on the road as long as possible. And it's a reliable rig the last 18 years!

So i will do my very best to set this Dana35 to specs and hope for gear smoothness. It's not so easy in europe to order parts and it takes much time/money.
But with the help of several forums, I am sure it will come to a good end.

Back to practice, I understand that bearing preload is recommended.
Bearings and races have wear, so the preload works against wear (?).
Preload is like a feeling and not easy to measure without special tools.
I want to use special tool (spreader) instead of tapping the differential in.
For preload i need to add very thin shims between races and housing?
So how should I take them in without a spreader?
First shims to housing -> than tapping down the diff?
Or first put in the diff -> than tapping down shims?

thanks for your patience!

Wolfgang
 
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SWIGIN

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I have never used a spreader so I can't comment on using one.

To tap in the carrier you place the shims in the housing then you insert the carrier into the housing.
 
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gmanpaint

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To help hold the shims in place inside the housing, while tapping the carrier in place,
I use a little medium red synthetic grease to butter the shims with.

You can do this Wolfgang, you did a great job on the rear axle rebuild! :thumbsup:
 
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wollimann

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Rear axle is not the same as front axle.
The front axle you must treat her like a lady, be carefull and gently;).

But I think I do it right (without a spreader)!
Testing back and forth good pattern are the result.
At the passenger side I replaced the shim stack (0.047 inch) with a solid
shim (0.049 inch). Grind an existing shim (0.055 inch) down with a belt sander -> am I crazy?
Driverside 0.017 inch, one shim.
Pinion high 0.035 inch (baffle+shim).

So with only the two shims it was very easy tapping the diff in. Only some hits to set it down.
The backlash was reduced from 0.005 inch to 0.004 inch and pattern are more optimized. I hope this is enough preload for the diff bearings?

The rest of assembly will be continued, changing the axle I don't know if I will find some time the next days?

At the end let me thank you by heart for your patience and support!!!

Wolfgang

Pic's shows mm, no inch
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http://www.forum.explorer4x4.info/viewtopic.php?f=17&t=119&p=893#p893


http://explorer-board.de/thread/131...differential-dana35/?postID=144615#post144615
 
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