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Symptoms of a bad center Dif?

116K views 36 replies 9 participants last post by  pzr2874 
#1 ·
At worke with not much time. The Wrx Im purchasing supposedly needs the center Dif replaced. Owner took it into Subaru, and after driving a tech said it was classic center Dif symptoms withvs classic cause(hooking up the right side wheels, spinning the left wheels playing). However, owner said driving it a couple weeks ago it was choppy driving while the center Dif caught/ failed, and the speedometer started going with the rpms, although the car wasn't moving that fast. Please give input.
 
#2 ·
I'm guessing this is a 5spd, so it has a viscous coupler. The two things that the car will exhibit if it is failing, is a tendency to hop or bind when the steering is at full lock (think low speed, parking maneuvers) The other is a whining, space ship-like noise on accelerating indicating the bearings in the transfer case (specifically the coupler, most of the time) are bad.

Other than that, there is no reason to cite a center diff. issue. The first necessitates a new coupler, figure on $375-400 for the part, 3.5 (shop time) hours to replace. The second is about $45 for bearings, same labor.

Transfer case repairs are really not that hard, since the trans stays in the car, just the exhaust and driveshaft have to be removed (oh and the shift shaft) It is a good time to replace the associated seals, while you're in there.

The description you gave of the tech's diagnoses, sound like it was done on a lift (wheels in the air) Have you driven the car ??
 
#3 ·
Haven't driven it yet. Its coming from Cali Saturday. Guy is trailoring it down and giving me a stupid good price, couldn't pass it up. 5 speed.

Honestly the way he's describing it sounds like a bad clutch... Almost. Slipping, gripping jerking. Except it hasn't dropped any gears. And the speedometer keeps up with rpms.

As im sure you know, the center Dif tries to split power to the rear/ front. Apparently when you have slippage and grip simultaneously in the rear and front this can cook the fluid quickly in the Dif causing it to fail. Apparently this was the cause of the problem, and the tech said symptoms matched. He said if you don't hold the wheel completely straight it starts binding.

Possibly the front Dif?
 
#5 ·
Lol, fair enough. I just want to get a jump on it. I already bought a center dif, hoping that's the fix. I'll resurrect this thread soon with first hand info.
 
#7 ·
The entire center dif unit out of another 07 manual trans, used with about 40k. There is some debate about whether or not this is a "wear" part, but most subaru's can make it their whole life without going through one of these. And they are all the same after 99, so it was fairly easy to find one.
 
#9 ·
So I drained the tranny last night, it looked like green metallic paint. There was a magnetic drain plug and it had collected a ball of shavings there size of a wad of gum. All very fine from what I could see. He had a new gear set installed, any chance a new gear set is like a new engine, in that it puts out shavings when new and should be changed within only a few hundred miles? Or is this a bad sign?
 
#10 ·
The green metallic paint description sounds like a blend heavy on the Redline shockproof. Having never done a new gearset (198K miles on my stock tranny, thank you !) I can't answer the shavings part, but normally I would say eww, not good. Wait for the guys with rebuilt boxes to chime in. How's it drive ? What are the symptons ?
 
#11 ·
I haven't ever seen shavings in my box, but I also changed the trans fluid 4 times in the first 3000 miles so the amount may have been so minuscule I just didn't notice
 
#13 ·
Having trouble popping the roll pin in the shifter linkage. Thats my last hurdle. Anyone that has advice, Im listening.

Cullen, I haven't really driven it. The transmission issues assured i wouldn't be able to get it up my support steep driveway. So we backEd up the trailer and dropped it on my shop floor.
 
#14 ·
The roll pin for the shift linkage actually is two pins, one little one in the center. Bang that out of the center with a small punch (1-1 1/2mm) first. Then the pin (3mm-ish) will pop out easier.

I recommend replacing all the bearings in the transfer case while you're in there, esp. since there was shavings floating around in there. Less than $100 for all from a dealer. The ones on the output shaft have will have to cut or chiseled off unless you have access to some good tools (like a hydraulic press with gear pulling attachments) Replace the shift shaft seal and output shaft seal, too.
 
#15 ·
I'm only pulling the rear of the case and it's staying in the car. I'm by means knowledgeable when it comes to transmissions, I just read a few how to's for the center Dif and said, hey, I can do that.

Are these bearings and seals accessible from the rear? I'm assuming the output is. As well as shift seal.
 
#19 · (Edited)
OK, Dif was definitely bad. Talked to a tech about to large "piston rings" (as I described then) I found rolling around in there back of the tranny. Turns out they are the clips that hold the center Dif together. Good, problem found.

However, there is A LOT of metal in here. And in inspecting visually the center Dif, all splines seem intact. But I'm actually picking what look to be teeth, be it gear or spline, out of the back casing. They are very small, maybe toothpick thickness, or a little thinner. Is it possible it's bad in a spot I can't see in the Dif? Are there smaller sets of splines inside that are not visible through all the holes in the Dif? I guess Im asking if I need to keep looking for the source of the ruptured metal.
 
#24 ·
Not in my experience. I can get a six speed around two thousand, a 3.90 rear around a hundred, an auto drive shaft, Sti clutch and slave cylinder for a few hundred. I could do the six for less than three. I imagine the build would cost more.
 
#28 ·
Brandon I know that you have had both the 5spd and the 6spd, and you would give up the 5spd? Im just saying from driving both, and even having a friend that went from 5spd to 6spd, granted its stronger, I just know Im glad I stuck with a built 5spd during my journey.
 
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