How to identify 3.54 diffs from 4.7 ones?

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Rodeo Joe

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As the title says really, I have searched this but can't find an answer.
I have got a pair of series 3 axles swb and was told one of the has a 3.54 diff. Is there any visual way to tell them apart?
Also are they interchangeable front and rear?
Thanks
RJ
 
Rodeo Joe said:
As the title says really, I have searched this but can't find an answer.
I have got a pair of series 3 axles swb and was told one of the has a 3.54 diff. Is there any visual way to tell them apart?
Also are they interchangeable front and rear?
Thanks
RJ
Click to expand...
interchangeable front and rear,
if diffs are in the case if you lock one wheel hub so only one can turn if it takes less than 2 turns of flange to get wheel hub to turn once its 3.54 if more its 4.7 ie 2.3 times
if diffs are out just count pinion teeth 10 is 4.7 ,13 is 3.54
 
Mine has 3.54 and they have plugs in the brearing housing but not the rear diff cover. I suspect they are early RR but of course they could have rebuilt the existing axles with the RR crown wheel and pinion.
 
:eek:

I always feel alarmed when people tell me oh yeah, I have a 3.54 in the back and a 4.7 in the front, I will get round to swapping the front one some day!
 
So as an update got both diffs on the bench now and 13 teeth on the pinion gears so should be 3.54 ratio.
The problem is some bugger has welded one of them solid.
My new question is this: Is the pinion gear the only difference or is the crown wheel different between 3.54 and 4.7.
If they are the same I should be able just to swap the pinion over, otherwise my plan to uprate both the series 3 swb diffs is going no where. I might just have to do the rear and get round to the front some day:rolleyes:
Cheers
RJ
 
Planet gears covered in weld. I should be able to swap both the pinion and crown wheel over though shouldn’t I .?
 
That's what I was thinking, if they have welded to create a fixed diff so long as you can get the bolts out the crownwheel and pinion should be usable.
 
Rodeo Joe said:
So as an update got both diffs on the bench now and 13 teeth on the pinion gears so should be 3.54 ratio.
The problem is some bugger has welded one of them solid.
My new question is this: Is the pinion gear the only difference or is the crown wheel different between 3.54 and 4.7.
If they are the same I should be able just to swap the pinion over, otherwise my plan to uprate both the series 3 swb diffs is going no where. I might just have to do the rear and get round to the front some day:rolleyes:
Cheers
RJ
Click to expand...
the carrier is different between 3.54 and 4.7 as the smaller diameter of the 4.7 pinion means crown wheel flange is nearer the center to allow crown wheel to sit nearer the center
crown wheels and pinions apart from been matched pairs so you cant mix them even if both are 3.54 but differ between ratios too cw and ps need swapping as pairs
 
So if the carrier is undamaged I should be able to just swap the planet gears then from a 4.7 diff as they are the same?
 
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