Hi - How do I tell if I have a limited slip differential (positraction) in my P1800? If I don"t, how hard is it to put one in. Thx...

Both the replies below are of course correct...but not quite as complete as could be. jack the car up (both rear wheels off teh ground) *and leave it in gear*. If it has ltd slip, it will be impossible, or very hard to turn either wheel. If no limited slip, car in gear, turn one wheel, and the other will turn the opposite direction.

Or, jack up both sides, *put in neutral*. If limited slip, both wheels will turn the same direction, and the driveshaft will turn too. If no limited slip, either only the one wheel will turn, as well as the driveshaft, or the driveshaft will remain stationary, and the other wheel will spin the opposite direction.

The burnout is by far the most fun... I recommend doing so on a dirt road though.

What year is your car anyhow? If its '69 or earlier, limited slips are rarer than hen's teeth. If you got one, take care of it. They ain't available no more.

If its a '70 or later (rear disc brakes), its got a standard Dana 30 rear with standard 27 spline axles shafts. You can get the posi units for them new from several manufacturers. Have a competent rear end specialist do the work. That is, a 4wd shop. They won't talk Volvo, but they'll know 'Dana 30' very well, as that rear end is common to Jeeps and several others.

-Matt
--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

Better reply yet, good on ya.

Dana type 30s showed up around the '67 model year, though, not only in the disc rear ends. Got 'em in both my '66 Amazon (musta been one of the first) and '67 1800S.

Thanks... I hope I didn't get it wrong.

Yes though, you are correct that Dana 30s showed up earlier. '67 I think.. BUT... The cars with the dana 30 rear, and drum brakes ('67-69, and maybe late '66 including 122) have 10 spline axle shafts, and there ain't no ltd slip available.

I tried and tried and tried and tried and tried to find one for my '66 wagon when I installed the Dana 30, which I got out of a '67.

Then I tried some more, and a few more times.

I contacted manufactureres, and they flat told me that nobody ever has ever made and/or installed such a crazy thing as a dana 30 rear end with 10 spline axles. Period. Let alone finding a limited slip unit (or even a gear locker) for such a thing.

That's why I say them folks don't usually speak Volvo. Nothin' wrong with them... they are correct. A Dana 30 rear uses 27 spline axles. Period. Except some Volvos built twixt '67 and '69. I think Volvo just had a bunch of Spicer 27 axles left over, and had Dana make the '30' unit to fit them spares. Just a guess.

-Matt



--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

'66 and earlier Volvos had 10 splined Dana 27 rear ends. Posi units can sometimes be found for those. I have one which I will probably put on e-Bay sometime soon.

'67 - '69 Volvos with drum brakes (120s & 1800s) had 10 splined Dana 30s which were peculiar to Volvo. LSDs were available as an option on those cars so they do exist but are very rare. Unfortunately, you cannot use a LSD from a 10 spline Dana 27 in a 10 splined Dana 30 diff.

From '70 on Volvo used 27 spline Dana 30s or the 1800s, 140s and 240s, although some 240s had the Dana 1031 which is a variant of the Dana 30.

LSDs are quite common for those diffs as Jeep used Dana 30s in a lot of their front axles. I have one of those too, which I'm thinking about putting up for auction on e-Bay.

If you really want Posi on a '67 -'69 1800 or 122 it's probably easiest to buy a disc braked Dana 30 rear end out of a '70-'73 1800 and put a 27 spline Dana 30 Posi or Detroit TrueTrac in it. Then you'll have 4 wheel disc brakes & posi.

Roj

'67 1800 S & various other Volvos

I'm not familiar with 240s... but I will definitely concur. The earlier dana/spicer 27 units as found on mid-late '60s Volvos have the 10 spline axles, and limited slip units can be had. Still hard to find though, but gear lockers can be bought new for about $275. But not really appropriate for a street car. Those rears were never installed in wagons though... they went straight from the Salisbury unit to the dana 30, the change between '66 and '67.

That oddball 10 spline axle dana 30 though is a whole different ball of wax. the limited slip unit ptional, but expensive as original. Most commonly found in 123GT models, which are rare in and of themselves. The absolute best option is to find one of them elusive disc brake 1800 rears, and make it fit to suit. Thats my plan with my '66 wagon. and the posi option is the only reason. I could care less about rear discs.

The 4wd shops I called told me the dana 30 was easily identifiable in that the axle stubs are not exposed. But the later drum brake Volvos DO have exposed axle shafts as we know. They are, to the best of my knowledge, unique to Volvo. And only for those few years.

--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

Can you put a Dana center section in a Salisbury diff?
How about finding 27 spline 122 axles?

Finding a 27 splined 122 axle would be tough. You'd have to find a '70 Amazon and those are rare. USA got it's last Amazons in '68. Canada had 'em in '69 (I own one) but I don't know if they got any in '70. I've heard of some being here in Canada but I think they may've been imported from Europe. My guess is that only Europe or maybe just Scandinavia got Amazons in '70 and those would've had 27 splined Disc braked Dana 30s.

That being said, the 1800s used the same axles as the 120s so like I said before you could get a hold of a '70-'73 1800 rear end it would go into your 122 but if yours is a '66 or older, it will take some fabrication to configure it for the earlier style suspension brackets.

I can't remember what year you said your Amazon was but I seem to recall you had an axle from a '67 in it. If your car is a '66 or older then a pre '67 Dana 27 axle should pretty much be a bolt in but there may be variations in the mounting hardware that I'm not aware of. If you had one of those earlier axles in your car then finding a 10 splined Dana 27 posi unit would be relatively easy. You could buy mine for example. ;)

Good luck,

Roj

'67 1800S
'69 122S
Numerous 240s

Correct again... but both mine, and George's cars are wagons... so whatever we stick back there will require fabrication. But wagon suspension mounts are pretty easy, so either the 1800 rear, or one from a 140 would probably do fine.

-Matt
--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

A 140 rear end might be more problematic and I'm not sure if it's the same track width. An 1800 rear end would be far easier. Keep in mind, however, the 1800 disc braked rear end will have a different bolt pattern (5 on 108 mm ~ 4.25") than your front wheels have (5 on 4.5") so you'll either have to get the front rotors and hubs from the 1800 and put them on your Amazons or make some other accomodations to standardize the bolt patterns.

Hang on a second... According to my interchange manual, not all 122 wagons had Salisbury rear ends. It appears to indicate that some wagons had Dana/Spicer 27s and 30s and the axle shafts and other differential internals are interchangeable with same era 120 sedans, 1800 coupes and 544s with Spicer type axles.

So that means you might be able to find a '66 or earlier 122 wagon with a Dana 27 rear end in it. If so, it would be a direct swap for your wagons and then all you would need to do is find a 10 splined Dana 27 LSD and you have your posi.

Roj

'67 1800S, '69 122s and other 240 sedans.

Hm... It'd be nice to find a dana 27 for a wagon, but I've never seen one. And I like the idea of having the beefier Dana 30.

Of course, if going wiht the 1800e rear, a fella would want to use front rotors at least off the same donor car. 1800e donor cars ain't all that common though unfortunately...

-Matt
--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

The dana/spicer 27 carrier is oh so close to that of the salisbury found in your wagons, but not quite. I don't think it would work. I did find a gear locker for the dana 27 that basically replaces the spider gear set, but fits inside the original carrier. That unit *might* be able to be fit to the salisbury rear. Except... the salisbury axles have...um...18 I think splines, so you'd have to use the dana 27 axles, and the outer bearings are totally different. Someone with access to a good machine shop could probably cobble something together that would work.

Dana 30 is a good bit bigger all around.

--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

Jack up the diff, and spin one wheel. If the other side spins in the same direction, it's got posi. Opposite direction, no posi.

Jack the rear end up, spin one wheel. If the other one spins, the you got limited slip. Or you could do the fun way, take the car out to a deserted street and do a burnout!....if there are two thread marks, its a limited slip. Or you could take it off road in a muddy field....get the idea? heheh. Only way to put one in is to find a rear end that has one and swap the rear end.
--
and the bricks keep on rolling....