Axle ratios

[Hugo]

I had the bright idea of swapping the 3.54 diff on my 1970 US import OTS for a 2.88 CWP I picked up on ebay. Having spent ages carefully setting the pinion height, I find the crown wheel doesn't fit. In round figures it is a tenth of an inch thinner than the 3.54 crown wheel, while the pinion is half an inch bigger across the pointy end. I gather there are different thickess carriers, but according to what I have found, the 'break point' is 3.76 and (numerically) below. So both my original 3.54 crown wheel and the 2.88 crown wheel should be on the same side of the 'break'. So now I have rear suspension bits all over my garage floor and I'm stuck. 2.88 seems to be a pretty rare ratio, although I can get a 3.07 CWP from various suppliers, but how do I know I won't end up in the same position again? Any ideas?

[christopher storey]

I am only guessing, but it sounds as if the 2.88 set you have may be from an XJS, which may have had a different casing. What you can do to get round this I don't know, but searching for Dana gearsets may give you the information you need

[mgcjag]

Hi Hugo.....PM sent...Steve

[Hugo]

Thank you - but from what I can find, the housings are all the same (or the same size, anyway). There are variations in the shimming process for the crown wheel. Mine unfortunately entails pulling the bearings off to fit shims behind them on a trial and error basis. And even using a barbaric medieval 'casing spreader' to jack the housing apart so you can get it all back in with the requisite pre-load. In ractice it's easier to just wallop the diff in rather than risk cracking the casing. Why they adopted such a system when they could have had screw adjusters I cannot fathom, especially as these are mass-produced units. But that isn't what has me stumped. You may well be correct that this is an XJS or similar CWP, but if it's a Dana 44 it, should, according to everything I've found online, fit. Maybe if I could find a thinner gear carrier, it would. But this is the first time I've ever worked on one of these, (and I hope it's the last) so there's a whole lot I don't know about them, and most of what I do know is un-printable.

[rswaffie]

It might be worth contacting Alan Slawson at AJS - he may be able to help?

[44DHR]

Hugo,
Generally it can be difficult to fit a gearset, (Crown Wheel and Pinion) from a Dana 44 axle into a Salisbury 4HA casing without undertaking modifications.

1). Did you just buy the CW & P as a separate matched set, and not in any form of casing ?
2). Are there any etched markings on the end of the Pinion and any markings on the circumference of the CW ?
On a HA Salisbury axle, whether it be in a complete axle casing or a separate cast differential casing, as on the E Type which uses a 4HA gearset, the setting dimensions such as the Zero Cone Setting is etched on the end of the Pinion. I am interested to know what marking/etching is on the new gearset you have bought.

3). Does the Pinion have the same number of splines ? Often the Dana Pinion uses a different drive flange in the form of a yoke and has a different number of splines compared to the Salisbury Pinion.
This post and the enclosed links may help in terms of difference and parts required :-
viewtopic.php?t=13728

4). When you mention the “Gear Carrier” are you talking about the mounting flange on the differential case. Is this a Salisbury Power-Lok differential ?

Regards,
Dave

[Hugo]

1) Yes I just bought the gears only as a matched pair.
2) The pinion cone height is marked as +.003. Trouble is there is a bit of confusion as to what the 'zero' measurement should be from the crown wheel centreline; my manual (on disc) says 2.625", but I have heard other say 2.635". But my manual also says you adjust the back-lash by shiming the drive shaft flanges across side-to-side, whereas on mine the shims are behind the damn bearings, which makes it a lot more fun!
Also engraved on the pinion is the number 1187, plus a zero on the right and what looks like a 3 on its back on the left. Stamped on the shank of the pinion is "4HA 017 63 49x17" and underneath "STL B81 DAY B".
The crown wheel also has 1187 engraved on it, which is reassuring, plus the following stamped; " 4HA 016 63 49x17 STL A81 DDY"
3) Splines are the same (coarse square splines).
4) The bit that hold the differential gears, which the crown wheel bolts to. It is a 'powr-lok' but I don't know whose. The book says Thornton but that clearly refers to an earlier type of diff.

When I began this job in all innocence I knew nothing about these things, and I was very surprised to learn that the Jaguar diff is, allegedly at least, "the same as the Dana 44". I have no idea of the connection between Salisbury and Dana. I have done a bit of reading up on the Dana 44 and, apart from learning that it has been in production continuously since the 1940's, I am amazed that anybody would use such a labour-intensive piece of equipment on a mass-produced car. Mind you, that goes for everything about the entire construction of the E Type. How on earth did they sell for half the price of an Aston?

[Tom W]

There were 3 types of diff used on the Series 2, all Salisbury 4HUs. Which you have can be identified from the chassis number and the parts book, assuming your diff is original to the car. They’re superficially the same externally, but there are differences inside.

Beyond Series 2 E-type into other models with the IRS there are other variations, including some diffs that were Dana 44s, not Salisbury 4HUs. 2.88:1 is rare for an original E-type ratio, I think being only used on S2 autos for some markets. It was common on XJS and some XJ6/12 though, and this was also the era when the Dana was used.

I was under the impression the carrier on the 2:88 was different to the rest, moving the crown wheel mounting face further from the pinion centre to accommodate the larger pinion. However, I can’t find reference to this in the parts book.

The easiest and cheapest way to convert to 2.88:1 is to just buy a complete diff.

[Hugo]

The plot thickens! Barratt's list three types of diff, each with and without 'powr-lock'. I think it is pretty clear that mine is the latest type (it's a 1970 car).
What you say about the carrier makes perfect sense. But according to the online info for Dana axles (which is what I thought I was dealing with) anything numerically below 3.76 (or was it 3.71?) should share the same carrier. They also speak of 'thick' gears to fit the thinner carriers if you are lowering the ratio (in terms of speed) which a lot of people seem to do with off-roaders.
I'm almost tempted to heat the ring gear & get it machined & re-hardened, but I don't know how much to take off and it would probably come out looking like an old gramophone record that's been left in the sun. The carrier flange is already pretty thin so I wouldn't fancy machining it down very much.
What is the tie-up between Salisbury and Dana?

[44DHR]

Hi Hugo,
Just a quick reply as I am outside on a lockdown painting job and just in for a rest.
(I started writing this before your post above came in).

1) and 2). Good, the two numbers of “1187” should confirming the Pinion and Crownwheel are a matched pair. Plus, the 4HA stamped on the Crownwheel means this is a Salisbury differential.
The Zero Cone setting for a 4HA, (and 4HU) differential is 2.625 inches. I don’t recognise your 2.635 inches for any HA/HU differential.
3). Even more confirmation that it should be a Salisbury Pinion.
4). Racking my brain from my Hot Rod days and reading through some of my workshop notes, I believe their are two Differential cases, be it a Powr-Lok or a conventional differential, which I knew as Shallow and Deep cases. The Shallow case moves the mounting face further away from the Pinion centre to take account for the wider Crownwheel bolted to it than those thinner Crownwheels bolted to the Deep case. This difference in cases is confirmed by Tom’s comment above. In my notes, I have a rough sketch that I made and I stated the Shallow case was used on ratios 3.54 through to 2.88 and the Deep case was used on ratios 3.77 through to 4.5. So, the 2.88 should be the same case as a 3.54.
I can explain the relationship between Salisbury and Dana at another time, but basically Salisbury came first and is not as some believe originally a UK company, but an old established American company.
Like Tom, I usually just fit a complete 2.88 diff from a Salisbury equipped XJS for axles I have worked on for people.
Regards,
Dave

[Tom W]

Edit: Dave’s reply was posted whilst I was typing this.

The Salisbury 4HU is very similar to the Dana 44, but they’re not directly interchangeable internally. I don’t know exactly what the differences are, but they’re the same basic design.

As I said, your cheapest option is just to buy a complete diff from an XJS. I have a late S2, and the diff I bought from eBay was externally identical. The big appeal of the 2.88 is it is (was) readily available complete 2nd hand. I think if I were going to rebuild a diff, I’d consider one of the ratios that were specified for the E-type originally.

[Hugo]

Based on the fact that mine is a North American car, and that the entire rear end has already been rebuilt while in the States, I'm wondering whether somebody may have fitted a Dana gear carrier?
As Dave 44DHR says, the 3.54 should use the same carrier as the 2.88 according to the info online (although that info was posted for Dana not Salisbury axles). My old 3.54 diff has 4HA stamped on the pinion, so that is presumably a Salisbury item also.
My reference to a 2.635" pinion height comes from our old friend Paul Cangialosi in Florida, who has posted a video;

Now that is a described as a Dana 44, but it looks exactly the same as mine - coarse splines and flange rather than yoke & all.
I am still puzzled how two diffs can be identical but not interchangeable. But the more I get into this job, the more puzzled I get. Life used to be so simple!

[Tom W]

They’re not identical, but the same basic design. The Dana manufactured diffs uses on Jag IRSs were used, I think, on the 3.6 XJS. They have a square input flange, and the brake calipers bolt directly to the diff housing, not the output shaft carriers.

The Powr Lok diff was standard for US cars with the 3.54.

I can’t remember where I read it, but I thought there were 3 carriers. One for 2.88, one for 3.07, 3.31, 3.54, and one for the lower ratios than 3.54, used in the saloon cars etc. There was also 2.93:1, but I don’t know which carrier that uses. Like I said, though I can’t find reference to this in the S2 parts book, although most of the diff internals are under Salisbury part numbers, not Jag numbers.

[44DHR]

Hugo,
Just to confuse you more, the Dana 44 used to have a coarse 10 spline on the Pinion shaft, but in the mid 1960s changed to the fine 26 splines. So, a very early Dana - or more correctly originally a Spicer as they then became part of Dana - could have the coarse 10 spline.
I personally think that your new CW and Pinion are a Salisbury gearset and the issue is getting them mounted on the correct carrier to obtain correct alignment.
As regards if a Dana 44 gearset can be fitted into a Jaguar 4HA case, I still believe this possible, but modifications are necessary. Details of the parts required can be seen on my post #6 above and the that post’s link referring back to an earlier E Type forum post and the links within that at post #4 within that discussion.
Hopefully this may also assist and covers the history of Salisbury and Dana :-
https://forums.jag-lovers.com/t/pinion- ... 120/372486

A bit of a daft question, but is it possible for you to go back to the Ebay seller that you got the CW and P and ask where they came from and do they still have the diff carrier ?
Regards,
Dave

[Hugo]

In an attempt tp get the Salisbury/Dana relationship quite clear in my head, I found this online. I know, "If it's on the internet it must be true". But this sounds plasuble;

"Jaguar first used the Dana 44 in an IRS in 1961 for the Jaguar E-type as well as other models. It was used through 1996 (Jaguar IRS Article). There are some differences in the Jaguar Dana 44, however. The differential (possibly the entire axle assembly) was made by Salisbury, a U.K. division of Dana Corporation. The ring gear in the Salisbury version uses slightly smaller mounting bolts and the pinion shaft is a different diameter than the common version. Naturally the cast housing is also unique to the IRS model. Standard 8.5" Dana 44 ring and pinion gear can be used in the IRS model through the use of a special installation kit which includes special shouldered bolts to mount the standard ring gear to the IRS carrier and a special pinion bearing set to fit the standard pinion shaft to the IRS housing. Gear distributors with knowledge of the Jaguar IRS should be able to get the installation kit. US Dana 44 gears are slightly stronger than Jaguar gears, and Jaguar gears are higher priced, but once the installation kit price is added to the lower US gear, prices cost is about the same. If Jaguar makes the needed gear ratio, there isn’t much difference in strength. The consensus in the hot rodding community is that the Jaguar IRS is good for up to 500 hp from the factory. Most V-12 Jaguar and E-type six-cylinder models used limited slip versions, other models (mainly the XJS) used a standard differential stock with limited slip as an option.
http://www.dana.com/corporate-pages/history 9
Spicer buys Salisbury, Dana buys Spicer. Dana opens UK Salisbury plant in 1925. So, USA owned, built in UK, who also used SAE, not metric until?..https://en.wikipedia.org/wiki/Metricati ... ed_Kingdom"

[Hugo]

Hugo,
......
A bit of a daft question, but is it possible for you to go back to the Ebay seller that you got the CW and P and ask where they came from and do they still have the diff carrier ?
Regards,
Dave

No - I bought this ages ago & it's just been sitting on my shelf waiting till I plucked up the courage to do the job. What prompted me to do it now is that I foolishly attempted (and ultimately succeeded) in dropping my engine & gearbox in from above, and with all the angst that that entailed, I (ahem) forgot to fit the propshaft.

[Hugo]

Starting to make sense - I just found this quote online;

"2.88 & lower (2.69?)
3.07-3.54
3.77-4.10 & higher
May be out a tooth here or there, but that’s the basic grouping.
3.54 can’t swap to 2.88 without other components swapped."

So it seems there are three different carriers, not two as stated elsewhere (that may of course be a difference between Dana & Salisbury) and, furthermore, it explains why my gears don't fit. All I have to do now is find a 'thinner' gear carrier that will take my 2.88 gears. At least I now understand what is going on, which is more than I did this morning.

[Tom W]

That’s what I said above.

There are only 2 carriers as far as E-types are concerned, one for 2.88, and one for everything else. Since no one wants to go lower than 3.54, no one needs the 3rd option.

[Hugo]

A lot of people do seem to want to go lower than 3.54 - not on E types obviously but on various track cars and off-roaders. Plenty of 4.xx's and even 5.36 gears out there. 2.88 gears are hard to find though. The after-market even supplies spacers so you can fit the thinner crown wheels to the thinner carriers. What I have is the opposite however.
It may be that Dana & Salisbury are different, but everywhere I've looked it says there are only two carriers; one for 3.76 up and one for 3.54 down (numerically). But apparently there is also one for 2.88 (and down).
Personally I can't see the point; most say it's to lessen the rotating mass, but if you're taking it off the crown wheel and adding it to the carrier (or vice versa) it's going to come out pretty much the same either way.

[PeterCrespin]

That quote was probably either from me or recycled from one of my posts, perhaps. Somewhere here is my photo of all three carriers in line, clearly showing the range of 3 flange offsets.

I still have the spare empty 2.88 Powr-Lok carrier (subject to confirmation) if you want to pm me. I didn’t see anyone mention the lack of a drain plug on Dana cases by which you can immediately tell a bare empty casing is Dana. They were used intermittently in the mid 80s on XJ and XJS. I still have the 2.88 from my 84 XJ12.