Right, after the last blat of the season the car is now well and truly off the road for a diff rebuild / replacement. I'm struggling to identify what type my diff is.

It's from a sierra 4-speed 1.6 that had the smaller diameter drum brakes and push-in shafts. The tag reads

83BG4006 CC
4A 362 5F20

Now, how do I find out if this is a "large diameter" or a "small diameter" push in shaft diff?

Any help would be greatly appreciated!

Measure the driveshafts and post on here,someone will be able to tell you what you have fitted.

Just realized that the difference between the large and small size shafts might just be the shaft itself, and not the stubs that push into the diff. Is that true or not?

It's a 3.62 diff, it will be the standard 24mm shafts, only the desiel had bigger shafts 27 mm and the very small ones were on the 6 1/2" diff

Thanks! Out of interest, what parts of the diesel shafts are thicker / bigger? The part that fits into the diff (i.e. the inner splined part), the outer splined part or just the shaft between the joints?

It's all very confusing....

From the model of car (i.e. 1.3 or 1.6 sierra, 83-92) it sounds like it could well be a 6.5inch diff. On these the shafts have the same splines as the 7inch, but the CV joint on the inner end is different (smaller). These do come in 3.62 ratio is also consistent with 6.5inch diff (I have one in the shed).

The 6.5inch housing looks the same as the 7inch, but the outputs don't stick out as far and they are a few kg lighter.

The definitive way would be to measure the diameter crown-wheel, and the dimensions of the inner CV joint stub.

Matt

Right, the plot thickens...

I've removed the diff from the car today. The crownwheels looks to be a 6,5 inch (but it's difficutl to measure with it still inside the diff), but the diff end of the push in shafts have 23 splines. According to this site: http://www.matt_phoenix.talktalk.net/Rear_end_Sierra.html this corresponds to a 6,5 inch diff. In which case i'm screwed as I'll need new shafts + diff since no-one sells recon kits for a 6,5 inch diff.

So: can anyone confirm that "normal" push in shafts have 26 splines at the diff-end?

Matt, it seems I quoted your site above, correct?

Right, I've took the plunge and taken the diff apart. It is a 6,5" diff and part numbers are:

Bearings: SKF K-LM29749
Oil seals (output shafts) 83BG-3K169 A5B (or A58, I'm not sure on that one).

Can someone cross reference these to a 7"rebuild kit? It might just be that these two diffs use similar bearings.

Thanks,
Sebastiaan