diff identification

[cadetchris]

having eventually got sick of my speedo just thinking of a number, i have decided to check the diff ratio.
having been sold the diff by a man who is a specialist in all things wolseley 1500 and on the authority it was a wolseley 1500 diff, i was very very surprised to find stamped on the main wheel in the diff instead of the usual 3.77 for a wolseley, 9.41 instead.

not a wolseley 1500 diff in my book.

"ATA 7091 MOWOG 9.41" is the full text stamped on it.

so, two questions:

1. whats it from?
2. what speedo head do i need to get an accurate speed reading?

[bmcecosse]

41 / 9 = 4.55 In other words - it's the useless diff from a 948 Minor - maybe some use if doing hill climbs or sprints - that sort of thing. Hopeless for a road car with any sort of power. Hope you didn't pay more than £5 for it!

[cadetchris]

i have no idea how much dad payed for it, it was several years ago.

well, i am at a loss what to do now, do i keep this diff, which does make the car nice and nimble and it really flys, and thus get a speedo head to match

OR

do i get a wolseley 1500 diff and keep the same speedo?

[alex_holden]

Or fit a 4.22:1 diff which gives a good compromise between acceleration and cruising RPM for a standard 1098 engine.

[bmcecosse]

I had a great run to Peebles and back yesterday - with the 3.7 diff my Trav cruises very nicely - had to use third very rarely - but since it is pretty much = 4.55 top gear, that's no hardship!

[cadetchris]

could i just replace the crown wheel and pinion instead of the whole thing or is it advisable to replace the whole lot?

[bmcecosse]

You could - but where to find the new crown wheel/pinion! And then it would need setting up.......... Just run what you have - it will be fine meantime.

[cadetchris]

esm do do them, but for the price, ill stick with my duff diff. what speedo head would i need to get an accurate(ish) speed reading?

[PSL184]

It depends on what size wheels and tyres you have fitted also....?

[cadetchris]

standard size rims, just slightly lower profile. however i am changing back to original tyres and rims,

[mike.perry]

Fit a gold 1504 TPM speedo from a 948 car or a black speedo from a 1098 LCV which also has a 4.55 diff. Then check with a sat nav.

[cadetchris]

excellent, ill trawl flebay for the nice gold one.

it would be number 5 speedo for the car, but what the heck, cheaper than getting a speeding ticket anyday

[alex_holden]

excellent, ill trawl flebay for the nice gold one.

Bear in mind the late gold speedos fitted to early 1098 cars were calibrated for a 4.22:1 diff. The speedo in my trav's been faulty for years - I had to get used to judging speed by the rev counter instead!

[bmcecosse]

And 'rev counters' are deadly accurate.............NOT!

[alex_holden]

And 'rev counters' are deadly accurate.............NOT!

Mine's not too bad; I re-calibrated it against a frequency counter. The problem is remembering what RPM equates to 30, 40, 50, 60MPH in 4th. I should write them down and stick them to the dash (or get the speedo fixed!). I've never had a speeding ticket though.