In my recent post I have verified via a stamping my early MK2 has a 4HA axle but with a 4.55 ratio. Car was originally a 2.4L but now has 3.8L 4-speed with OD.

I an wanting to change out the 4.55 with a 3.77, but they seem extinct. I have a lead on a complete 4HA axle with a 3.54. Its expensive and so is the shipping and I really do not want the 3.54.

So after a lot of searching can a DANA 44 CWR like this be fitted into my axle? Cost is about $400

https://www.yukongear.com/shop/yg-d44-373#

From what I have read, the 10 bolts may have different hole diameters, the splines on the pinion are different, so is a compatible flange available, etc, etc.

Can this be done and what has to be done to fit?

I still would love to find a original 3.77 as this would be a "bolt-in" assuming a successful setup.

So who has a 3.77 sitting around?

Help

jjsandsms

 

I'll chime in as no one else has. It will at least push your question to the top of the forum.

I don't know the answer to your question. I do know that E-type and XJS owners and kit car and hot rod builders have run into difficulties with Dana Spicer 44 vs Salisbury 4H differentials. Apart from the points that you mention, a change in ratio involves a larger pinion and thinner crown. A lot depends on how those are accommodated. It might be safer and cheaper to remove a 3.77 crown and pinion from the 4HU diff of an older XJ6. I think the series 1 and early series 2 used a 3.77 in the manual overdrive transmission. They changed to 3.54 and 3.33 for the series 3 XJ6. The link below may be of interest:

https://www.mig-welding.co.uk/forum/...n.99428/page-4

 

Can I assume the 3.77 out of a 4HU diff from a early xj6 is the same as a 3.77 in a 4HA? if so that opens the possibility of finding a 3.77 a bit more.

Thank you very much!

jjsandsms

 

The conversion in the link I gave took the internals from an E-type diff and put then into a 2.4 Mk2 axle, so the answer is yes. It's probably better to be a bit careful as I think the later IRS diffs may have moved to finer splines (and of course some later XJS diffs are Dana 44). I'm fairly sure that you would be safe with the internals from a 1960s or early 1970s car, S-type, 420, E-type, Mk 10, 420G, XJ6 series 1.

On Barratt's website, the CWP for the 3.4 Mk2 and 3.4 S type are both listed as part 4HA-105/7A, unfortunately no longer available.