Rear axles don't want to spin

[BoostedSubie]

I have encountered another problem on the Legacy I just finished building. The car runs great but I went on the first drive on Sunday and it felt like the rear end was dragging. I never went over 30 mph, just did 2 laps around the block thinking it may have been the brakes and that they'd free up. So, pulled it back in the garage and put it back up on jack stands with all 4 wheels off the ground. I tried to spin the rear wheels and could feel a great deal of resistance, took the wheels off, tried spinning the hub by hand and it took a fair amount of strength just to spin it. Then tore all the brakes off to make sure it wasn't the calipers or the ebrake hanging up, still did it. Took the knuckles off (stub axles) and still had resistance in trying to spin the axles by hand. By the way, the fronts spin just fine. So, my first assumption was either the rear diff or the center diff. I should note also the transmission is a 98-01 Forester 5 speed with an 01 Impreza RS VLSD rear diff, both are 4.11. I ended up removing the diff and replacing it with another 4.11 VLSD tonight and still have the same results, like the rear is bound up. So, that leaves the center diff I'm assuming. I just was unsure as I bought the trans from my work used with around 100k on it. Any ideas? Am I right to assume the center diff? Everywhere I read on people having issues with the center diff, none seem to be as extreme as mine.

[Alphius]

Pull the rear driveshaft section and try to spin the trans output.
Also at that time try to spin the rear wheels.

Your front end is off the ground when you are checking this, right? If it's on the ground you will feel resistance as the center diff transfers some of your turning torque to the front wheels.
Make sure at least one front wheel is off the ground during your testing.

[Legacy777]

Are you positive the trans is a 4.11 final drive ratio?

[Alphius]

Are you positive the trans is a 4.11 final drive ratio?

This is kind of what I am getting at too.

[BoostedSubie]

I am 99% sure it is 4.11. I work at a salvage yard and thats where I got it from. Its from an 02 Forester, the Foresters only came with 4.11 manuals and 4.44 autos for that year according to Hollinder. I will double check tonight to make sure though, and yes, all four wheels are off the ground while checking everything. Since most the cars brought into our yard are wrecks, most are towed in by outside tow companys and I have heard of incidents of tow drivers not using dollys when they tow a Subaru and destroying the center diff. Another contributing factor could be my driveline. Since, i used a newer trans with a newer rear diff, I had no idea as what driveline to use so I took measurements of a 93 5spd driveline and walked the yard measuring every driveline out there from 95-10. I ended up using a 05 automatic Legacy driveline which fits nice and snug. I have spun the driveline while unbolted from the rear diff and it felt good, its once I bolt it to the rear diff it starts having issues.

[BoostedSubie]

What would be the best way to go about testing the center diff. My boss also gave me another 4.11 Forester tranny for free as they were going to core it out due to the high mileage of 252k miles so if my center diff is bad I'm kind of reluctant to throw in a center diff with that many miles. If I have to I can take the tranny back out and exchange it for another. I just want to pinpoint the problem before I do all that.

[mike-tracy]

You can just swap center diffs without pulling the tranny off the car if you want to try it with a low mileage unit. You should have a phase II Forester tranny, which means the center diff is integrated into the tailshaft housing. You could put a phase I unit in of that's what you have to work with, the center diff is separate from the tail section so you'd need both pieces.
http://www.subaruforester.org/vbulletin ... hem-46979/

Also I'm probably missing where you posted the year, but you should have gotten a manual drive shaft off a same generation of legacy, either sedan or wagon. I'm surprised that an auto fit at all, but I don't feel that is the problem.

[BoostedSubie]

Thats what I wanted to do, was just change the center diff but in order to get one from work, it has to come from a core tranny. They aren't willing to take a good tranny apart for one part which sucks but what can you do. At the moment, that high mileage tranny was the only core we had. If it were a phase 1, I can just get a ton of them from our pull n save department. I wanted to stick with the phase 2 center diff though as I've heard they are a little better, is that true? As far as the driveline goes, the 05 auto Legacy came out to be the best fit based on comparison to original driveline but with the newer style rear yoke. I just had wondered about the driveline as bolting up to rear end was kind of a tight fit. My buddy has been trying to talk me into making it rwd since I have to repalce the center diff anyway, he says might as weld it up while its out. Would probably be fun for awhile but would be replacing rear diffs and axles quite often I imagine. By the way, thanks for the help , and Happy Thanksgiving.

[BoostedSubie]

Here is another thing, when I had the first rear diff in, I would spin a front wheel with the trans in neutral, and the rear would spin with it. Now, with the rear diff I swapped in the other night, I spin the front and the rear doesn't spin weather it's in neutral or in gear. I know this diff is open as I spin one side forward the other side spins in reverse. The diff from before was VLSD.

[BoostedSubie]

Today I ran the car through first gear while up on the jackstands still, shut the car off, then checked the rear hoping that maybe the clutches in the center diff are just stuck from the tranny sitting on a shelf for so long or something. Well, then I tried spinning a rear wheel by hand and now when I spin the rear in neutral, it spins the front wheels with it.