My car has 60k on it, and since my tranny is out I picked up new diff bushings and pulled the diff mount to install them. But the old ones look just fine.

I don't have any reason to suspect a problem with the old ones, and in fact a previous owner may have replaced them alreadly (an avid autocrosser who may have been concerned with wheel hop). Yes, I'm being a little cheap, but I've got bills to pay right now.


1) should I replace them? Can good-looking bushings still be worn?
2) will the old bushings be damaged in the removal process?

Thanks

Dave

 

I've seen bad diff bushings, both in cars with around 100K on them. I've driven, seen and owned A LOT of other FDs and the diff bushings were all good.

I think bad diff bushings isn't a common thing but it isn't unusual either. Of course replacing the stock bushings with solid bushings will reduce diff movement it'll also increase noise and/or vibration no matter what anyone says.

I wouldn't replace them unless you know they are bad. It isn't too hard to get the diff mount out.

 

I exploded my 104k stock bushings at the track. I'd highly recommend replacing them if you are going to drag race. Mine blew and the subsequent wheel hop exploded my rear diff a few passes later.

 

I agree that those look really good but then again you've already got the new bushings on hand and the mount out. May as well replace them.

If I knew they looked that good in the car I wouldn't bother, but having everything out already I'd go ahead.

Mine were quite obviously bad as one of them was ruptured. There was an obvious split in it.

 

Looking good in your hand and what they look like under load are two different things. Since you have the differential mount out and already have the replacements, replace them (as Damon suggested). Then you won't have to worry about it or kick yourself after you (possibly) have to pull it out again later.

BTW, "anyone" has been saying that solid differential bushings will increase noise and vibration since day one. Maybe "someone" has a reading comprehension problem or poor long-term memory...

 

On a side note, turbojeff said getting the diff mount out wasn't that hard, but he may have more experience than me. how hard would it be for someone without air tools and that is still learning auto mechanics?

 

Search jimlab's description as he's posted it many times. It is not hard at all. I just did mine recently exactly as jim described and had no trouble at all.

 

Thanks, I'll do that. Not something I'm planning on doing soon, but when I saw the thread I just got curious as to how hard it was to do.

 

I just did it without air tools. I used Jimlab and Damian's instructions.

Getting the PPF apart without air tools requires a good bar and cheater - I used my full jack handle, 1/2" drive x 18" breaker bar. Then remove the propeller shaft (make sure your match mark is good and durable. Then I lowered my jack supporting the diff to let it roll forward.

The one trick is getting access to them. First, you have to remove the horizontal bolts between the mount and frame - I managed that by using a short 17mm 3/8dr socket on an extra-long 3/8 socket wrech and putting it in vertical alongside of the diff. I had to move the diff around to get a little more space once. Fortunately, once it broke loose, my fingers were enough to reach around and remove the nut cause you can't get a wrench on it. Before you pull those bolts out, separate the e-brake cable bracket from the diff so it won't get pulled on. Then pull the bolts and let it lower.

Now I found that I needed the full 18" breaker and 17mm short socket to get the top four bolts started. The fit between the mount and studs is pretty tight, so expect to wrestle a bit to lift it straight up before it will come out.

That's as far as I've gotten

Dave

 

You do not have to remove the PPF or the drivehsaft to install the diff bushings. All you do is drop the undercovers, unbolt the catback from the cat, remove the single aluminum cross brace that passes through the PPF at the rear and then remove the two bolts that go through the diff bushings. The whole diff/PPF/axles and all will then drop a few inches and allow room to get to the nuts on top of the diff. I removed the nuts with a plain open end wrench and a jack handle as a prybar. Once the nuts are off the diff mount can be pulled out the passenger side.

 

True, but he was removing his transmission, apparently. I almost posted the same thing.

 

All I can say Jim is that your solid diff bushings are the ****. Noise & vibration????????Maybe the guys with the stiffer R1-R2 suspensions have these problems. I have a touring with stock catback and I can barely hear the rear end. Cuts down on the wheel hop also.

 

My RP Solid Nylon diff bushings did NOT add any noticeable vibration. FYI.

The ones in the picture look good.

 

You might be surprised after changing them. I had no reason to suspect my diff bushings (65k on street driven car) until I was hit from behind in an accident and one of them ruptured. After replacing them I was surprised on how much better my car felt. Hard to articulate, but it just felt more solid, maybe a hint of what it must have felt like brand new.

 

Yeah, my tranny is out already, so if you're just going after the diff mount it makes sense you can just separate them from the diff and tilt the diff down. Thanks for clarifying that.

Sgtblue: Neither of them is ruptured or looks to be remotely close to doing so. I'm leaving them in.

Interestingly, the mold marks on the original rubber parts say "3" and the new set say "13".

Dave

 

At the very least, I'd put a large screwdriver (or another suitable prying device) through the center pin of each bushing and exert some force on it to see if it noticeably separates from the rubber core under load. If you recall, did your shifter move excessively getting on and off throttle? Ever see it bouncing around? That'd be a good indication that you need new differential bushings.

If you're cool with taking a chance on them, then toss the mount back in and sell the replacements. None of us is trying to do you a disservice by recommending that you install them while you've got the mount out of the car.

 

^And to make it clear, I believed mine were just fine too. The accident was at very slow speed (frontage road in a parking lot) and the impact wasn't that hard, yet one ruptured. My thinking now is that they had weaken or worn with time and gave few symtoms. But comparing the ride before and after the accident, when they both were replaced, seemed to make a difference.

 

Ok, thanks for the extra info.

I did torque it around using a big screwdriver, and it seemed just like the new one.

But I think I changed my mind - if I already have the new parts, I'll put them in.

Dave