: Grinding when shifting into 3rd



DDS rollin a CTS
05-30-13, 09:21 AM
So over the last month or so my car has developed a grind going into third. It usually doesn't happen on upshifts, but instead happens when shifting down to 3rd at around 55-60 like to do a pass on a two lane highway or when slowing down. I took it in to the dealership (GMPP extended warranty and they gave me a new XTS to drive until its done so why not?) to have them take a look expecting them to find fault with the 3rd gear synchro, but now they're saying my diff bushing and rear upper control arm bushings are completely blown out and they think that might be the problem. Does that make sense to anyone here? I've been thinking about doing the revshift bushings on the rear anyways so now seems as good a time as any. I asked the guy at the dealership if theres any way I can convince him to go ahead and write it up as installing new stock bushings, but install the revshift ones for me instead and he said he'd have to look into it so fingers crossed. In the mean time I'm going to go ahead and order them anyways, just wanted to see if you guys that have done this recommend red or blue? I'm definitely going to do rear cradle, diff, and rear upper control arms, is it worth it to do rear trailing arms as well? FYI I daily drive my car year round and autocross it in the summer, but don't do track days. I'm ok with a slight increase in noise but want to keep it civilized. For comparison, for an exhaust I currently am stock with muffler delete and love it, and am going to install a full B&B system (headers/offroad pipes/catback) next so like I said, I'm ok with a bit of noise if thats the only difference between the red vs blue bushings. Now if I can just get the motor mounts and trans bushing sitting in my garage installed as well I'd be all set.

SevillianSTS
05-30-13, 02:45 PM
Hey DDS, get RED cradle bushings. They are not connected to a rotating assembly so it will not affect sound at all; they will help with the wheel hop immensely. Being "sideways" is so much smoother now =) I put in the BLUE diff bushing and it has increased my whine just a little bit; nothing a good exhaust or radio volume can't fix though. My diff is a 4th gen replacement with 4-5k miles on it, and it was practically silent before the bushing. I did put in the Creative Steel diff Block also.

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I'd come down and take you for a ride at Cars and Coffee, but I have a 1 month old baby; will be at least a few months until I make a longer road trip down there. ( He does like riding in the car BTW ) If you feel like driving up here I'd be willing to take you for a drive. I'm pretty close to South Bend.

FoD
05-30-13, 03:29 PM
The Revshift Blue Diff bushing didn't have any effect on noise to me. My diff doesn't whine though, so...

I agree, do Red on anything that isn't drivetrain related. I also don't see how bad diff bushing causes a 3rd gear grind on downshifts. The dealership probably visually inspected the trans (and by that I mean looked at the casing while it was still attached in the car) and then made up some junk about your bushings. But hey...let them do their thing and enjoy the XTS. I liked the one I drove!

DDS rollin a CTS
05-31-13, 09:04 AM
I called Revshift and they recommended going with red on everything on the rear end due to the wheel hop issues so thats what I ordered. I had to give up the XTS yesterday until the bushings come in, but then I should get it back. I won't sign off on taking the car back until I test drive it with them and make sure the grind is gone.

On a side note, I don't remember how much gas was in the car when I dropped it off but between their test drives and mine (they "couldn't reproduce the problem" even though I told them exactly how to make it grind so I had to go in and show them), the inaccurate gas gauge struck again. Apparently they ran out of gas driving it around for me to pick it up. They said they put some in, but I ran out as I pulled into the nearest gas station. Damn its embarrassing to have to push your car up to the pump.

Revshift
05-31-13, 02:30 PM
I did put in the Creative Steel diff Block also.

You have pinpointed the problem. Our diff bushing does not need any help from a block.

JFensty
05-31-13, 06:52 PM
You have pinpointed the problem. Our diff bushing does not need any help from a block.

Incorrect sir. I have the red cradle bushings and blue diff and I went from no whine whatsoever to a noticeable whine in all gears with light throttle. Nvh increased under load as well.

SevillianSTS
05-31-13, 09:46 PM
You have pinpointed the problem. Our diff bushing does not need any help from a block.

I figured the bushing was sufficient, but the block is good peace of mind that it'll never move :yup: especially since I went with the softer blue; trying to avoid potential wine.

robojesus
06-01-13, 03:45 PM
do you feel the grinding in the shifter?

DDS rollin a CTS
06-04-13, 04:04 PM
do you feel the grinding in the shifter?

Yes. Effort needed to shift into all gears, particularly 5th has increased over the same time period but only 3rd grinds.