Diff ratios

[stephen low]

Hey guys

Looking at an upgrade to my noisy jag diff.

It is a 3.54 ration LSD and am told you can't get new replacement crown and pinion for this ration but you can if it is a 3.07 ratio.

So what are you all running in your cars and what is suggested?

I've only a 5L and 15" 295 wheels.

Cheers and thanks

Steve

[Tom Wells]

Stephen,

It looks as if Richmond Gear is still making them in the 3.54 ratio - and lots of other ratios, and Summit Racing (among others) are selling them for under $200US.

Look here: https://www.richmondgear.com/auto-pa...ing-and-pinion

It wouldn't be a surprise if you found a Richmond Gear outlet down under...

The ring and pinion may fit OK as is, or it may need Dana 44 ring gear bolts which are a little different from the Jag - it's been too long for me to recall, but Richmond could likely clear that up for you.

I think you can probably find some rebuild parts for the PowerLok too (DuckDuckGo is your friend).

Hope this helps,

Tom

[jknich]

Jeep 3.31 or 3.54 Dana 44.

[kyleb]

G’day Slowy.
Got mine from Denis Welch Motorsport in 3.54 and mated it with an Auburn gear 19 spline LSD centre. Basically makes it a Dana 44. Vic Spiteri put it all together for me and it runs smooth as silk.. Not cheap, but I feel I’ll save in the long run!
As you know I’m putting around 600hp through it.
https://www.bighealey.co.uk/jaguar/axle-5?page=2
https://www.summitracing.com/parts/aub-542085
V&A Spiteri Jaguar - Independant Jaguar Specialists

[incoming]

The transmission. cam and a lot of other factors come in. I have an FIA car with a "slightly modified" 351w, wide ratio Toploader and 3.54 Salisbury rear. I can easily mistakedly start off in third gear and am constantly looking for fifth.
Honestly, I did 135ish once in my car. Secondaries opened for a minute.

[joyridin']

It would be easier to buy a new LSD differential and upgrade the gears to Dana 44 instead of using the outrageously priced Salisbury gears. Do you know if it is a 19 spline or a 30 spline? I switched to a Richmond Power Trax, and used Dana 44 gears. It was a pretty easy switch from the old Salisbury unit. The Jag set-up uses a collapsible sleeve on the pinion whereas with the Dana gears, you have to shims.

[jknich]

Also the Dana 44 pinion uses a different spline pinion yoke.

https://dazecars.com/dazed/Diff.htm

[stephen low]

Guys

I am constrained by what diff will fit the solid mounts on the car and more particularly by existing drive shaft / hub set up.

This was changed only a few years ago to allow me to use an outboard braking system from a later model Jag over the earlier XJ6 in-board brake set up. As well to properly fit new Vintage rims under my guards.

Perhaps should have done this then but its too late now, so am stuck using the diff housing I have.

Kyleb, I like your idea, though note replacement new crown and pinion will cost me about $1100 AUD on current exchange rates with the UK.

Still my goal is to silence the diff to best capacity and this may need to be the way.

Andy at Spitteri has asked if I can appear with the car and do a drive so he can hear my issues.

Planning that with the soft top on so he gets maximum exposure to my noise issues.

Send me a PM with your email mate so we can some further discussion off-line please.

Steve

[TbirdSmith]

I have 3.07 ratio and think it works well with 4L60E gearbox. 3rd is 1:1 and 4th is 1:0.69. Cruising at 120km/h is a pleasure at about 2200 rpm.

[sgianino]

also running a 3.07 with a 4 speed toploader and a 427 (496) CI

[novasscnc]

Jag Bits should be able to help I have 390 gear with a Richmond 5 speed

[xb-60]

Slowy, mine is a 2.78:1 diff. The effect is like a five speed box without a first gear. Easily enough low end torque to handle that.

Cheers!
Glen

[stephen low]

Thanks Glen

I've since had Spitteri check out the diff and there were bits failing so it had a standard rebuild.

Quietened it down a tad but I think the solid mounting if my main issue so just have to live with it, and only when the soft top is up anyway.

The ratio is perfect for me behind the TKO600 box I selected years ago so not changing ratios that's for sure.

Anyway all done some time back now.

Cheers and thanks for the comments.

[Dominik]

I find it extremely hard to suggest a ratio. I drove 90% of my Cobras in Germany, at cruising speeds of 130 kph (3.300 rpm) with the occasional blast to 6.600 on the highway. Those cars had 3.31:1. 4-speed, manual.

You change to 5-speed, you get used to the overdrive. You fit a 3.07, you get used to that.
You swap to a 2.88..., 6-speed with 0.75 OD...

The Lotus/Holden Omega revved 2.000 rpm at 200 kph.

My thinking was:

1. gear 100 kph, and more
2. gear 160 kph (good for ⅛ mile?)
3. gear 200 kph = ¼ mile
4. gear 260 kph

It's not a cruiser