Period Dana 27 Modifications

Be careful when removing the case half bolts. Type 30 Powr-Loks have left hand thread bolts. I'm not sure what the Type 27 uses and the manual makes no mention of it.

Watching this.....just cracked open my Dana 27 rear cover as part of a rebuild and found a powr-lok installed dated 1973 and it still looks brand new......but moving the vehicle into the side yard before Christmas in the snow revealed a spinning rear right tire, so I guess I need new clutch packs. Only place I've seen is Herm the overdrive guy. Are his parts NOS or are they new manufacture?

Please post pics of your disassembly and advise if the bolts are left or right hand threaded!

Patrick

PS mine is a 42 GPW and not an early 60s Amazon.

HRPufNStuf said:

Watching this.....just cracked open my Dana 27 rear cover as part of a rebuild and found a powr-lok installed dated 1973 and it still looks brand new......but moving the vehicle into the side yard before Christmas in the snow revealed a spinning rear right tire, so I guess I need new clutch packs. Only place I've seen is Herm the overdrive guy. Are his parts NOS or are they new manufacture?

Please post pics of your disassembly and advise if the bolts are left or right hand threaded!

Patrick

PS mine is a 42 GPW and not an early 60s Amazon.

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Herm the Overdrive Guy is the only source for parts that I've found and availability is hit and miss as he outsources the production of a few of the items. The other route is to buy a NOS diff from the army surplus guy on Ebay that sells them for $200 complete, almost the same cost as replacement parts honestly.

I'll update here when I get to taking things apart.

Long over due update here. Side lined by life as it may be but I'm getting back at it.

Threads are normal right hand threads, 1/2 inch head, torque in alternating pattern to 45 ft/lbs as per owners manual. I added a small dab of thread sealer and paint marks to mine for insurance.

I'll be pulling the rear axle this week, perhaps tonight. I have opted not to due the R+P setup myself as a good friend at a gear shop has offered to set it up for trade work. I'll see if I can get him to document the procedure though it's fairly well covered on YouTube and other resources. I just would rather not go through the bearing setup and measuring process without the experience of doing it beforehand (and the time needed to make the setup bearings). The turn around time of two days was also a selling point on my end as I have a 600 mile rally tour at the end of the month and want to get some break in miles on it beforehand and minimize downtime.

OK guys it's in and works, it works really well!

I pulled the axle out Monday night, had it blown apart Tuesday night, down to the gear shop Wednesday morning, back in my hands Thursday morning, back in the car Friday night. Had ample time to test on Saturday. First impression, man this car has so much traction now that on hard corner exits it needs more power, with 205 section tires it's not lacking grip now, could definitely step down a size if I wanted a more exciting driving experience. Most importantly though, NO INSIDE TIRE SPIN! It is quiet even on sharp low speed turns, used 80/90 GL5 with Ford LSD additive as recommended by the gear shop. Very pleased with this upgrade, looking forward to using it on some gravel stages but for the moment the grip on asphalt is immense!







The original axles out of my D27 were looking a bit questionable and I needed some bearing shims so I blew about a D30 I had behind the garage and low and behold it had some very nice axles. Since it was sealed up drum to drum the bearings were in great shape, telling by the blue IPD bushings it looked like it had been gone trough at some point.







Testing, closed course of course

excellent! i need to do the same for my 544

R32RennSport said:

There is one hitch though. These were destined for front axles in Jeeps and therefore lack the proper internal cross shafts and axle centering pins that are required when installed in a Volvo rear differential with drum brakes.

See parts 7-9 on your VP Autoparts website:

http://212.247.61.152/us/main.aspx?page=article&artno=1201060520

There is a solution to this though as another supplier has now came in to reproduce the proper cross shafts and centering pins.

http://hermtheoverdriveguy.com/d232527-powerlock-cross-shafts

I would also use this page in reference to reassembly or overhaul of these units when performing this needed operation as well as the supplemental Green Book:

https://cj3b.info/Tech/SB500PowrLok.html



More great reference material here:

https://people.physics.anu.edu.au/~amh110/Diff_LSD/diff_lsd_volvo_dana.htm

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Big bump on this, as I'm looking for info on the cross shafts.
It seems that Volvo used both types of cross shafts (with holes and centering pins, and without) on rear applications.
Is there a benefit to one over the other?

The centering pin is required on all rear ends with 2 piece axle bearing/race (544/122/1800 -'69) and early 140's. These rear ends need to have the axle bearing end play shimmed (or adjusted in the case of early 140's) and the ends of the axles need to butt against each other through the centering pin or spacer in the diff. Later rear ends use an axle bearing assembly that's not adjustable and therefore don't need the centering pin/spacer.

hiperfauto said:

The centering pin is required on all rear ends with 2 piece axle bearing/race (544/122/1800 -'69) and early 140's. These rear ends need to have the axle bearing end play shimmed (or adjusted in the case of early 140's) and the ends of the axles need to butt against each other through the centering pin or spacer in the diff. Later rear ends use an axle bearing assembly that's not adjustable and therefore don't need the centering pin/spacer.

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Awesome, thank you for the clarification. That it exactly what I was thinking as well.

Probably a little late, but these guys do sell a Torsen style diff for 10 spline Dana 30 Volvos

Quaife also makes 10 spline Torsen style diffs for both Dana 27 and Dana 30 Volvos.

Just a thought, but is it possible to modify 140/240 halfshafts to be used in 122 rear axle?

Of course 140/240 27 spilne differential is needed, but is there enough meat?