NEED HELP regarding Salisbury rear axel on an MKIV

[cobra06FR]

Dear All,

I won AK1317.
I know the rear axel is the original Salisbury part. However I have no clue what the drive ratio is for this axel 
I hear it could be 2.88 or 3.15 ? Does anyone know with reasonnable certainty what was mounted in 1989 ?
My engine is a 302 SVO  and the gear box is the Borg Warner T5WC.

If not, does anyone know how to figure out ?

The reason for which I investigate this is because I had a major failure of my gearbox.I think I need to chain it as both the entry 1 the main shaft have been dammaged. As the gear box has 50000 miles I think it is probably best replacing it rather that replacing these 2 shafts.
Obviously there has been a lot of different T5WC mounted on AC and mine does not have the gear ratios  corresponding to the only one new T5 produced by Tremec these days. And the new T5 from Tremec has got a 5th gear ratio of 0.63 whilst my BW T5 had a 5th gear ratio of 0.68. My 5th gear was already a "good overdrive" and thus I need to know my salisbury ratio as the new T5 is even longer.
I do not want to run into a non usable 5th gear.

hope this is clear. Let me know if not, I would try to rephrase.

Many many thanks in advance
Looking forward reading from you.
With my very best regards
Laurent

[dkp_cobra]

Hi L,

normally, there are ID tags claiming the ratio (directly or  two numbers which are the number of teeth of the ring and pinion) and maybe a further ID tag P-L saying that it is a power lock.

If these are missing you have to turn the input shaft and observe the output shaft. Maybe turning the input shaft ten times and look how often the output shaft has turned. If the differential shouldn't be a power lock (which I can't imagine) pay attention that both output shaft turn into the same direction with the same number of turns. Dividing both numbers gives you the ratio.

Kind regards,

Peter

[cobra06FR]

Many thanks Pete.
I'll look into this as you describe.
Very Best Regards
Laurent

[westcott]

The owners handbook shows a highspeed of slightly above 220 Km/h and a final drive of 3.31.
That makes sence because it is very hard to bring the car above 220 Km/h if you don't change the diff to 2.88.