Diff question

[Donny94]

Alright, recently got a 4 bolt 3.46 lsd diff & a 3 bolt 3.08 open diff, I've pulled the lsd centre out & put the 3.08 gears on & put it back into the 3.08, everything seems fine, but I have a slight bit of free play between crown gear & pinion where they don't touch when going from spinning one way to the other , is this normal to have a this gap in between directions?

 

[harrop.senator]

Depends on how much play it needs to have some backlash. With an IRS at a minimum you need to mark count the turns at a minimum when undoing the pinion and side bearing cups of the gears you're using.

Should also then use Prussian blue to check the lap before running it. And a dial gauge to read the backlash. Also make sure the side bearing retaining clips are put back on.

Should have you have just run the 3.46 diff a 3 bolt tailshaft and got the Speedo calibrated? Much easier and a decent upgrade.

 

[immortality]

Problem is, the 3.08 diff gears are for a M75/M78 centre and the 3.46 gears are for the M80. The M80 and M75/78 have ever so slightly different offsets where the ring gear bolts onto the centre.

 

[harrop.senator]

Ahh yes they do , I forgot 3.45 was 75 and .46 was the 80. Good spotting.