My car now has 130k miles and I've been noticing for a while what seemed to be extra movement from my rear end, a bouncing feeling sometimes that can interrupt power delivery (my suspension is sorted so I know its not that) and driving in manual mode around town has been clunky/jerky for as long as I've had the car. Letting off the gas in manual mode even causing the car to buck from the power cutting and engine deceleration happening. I got the diff bushing set from Figs and went for the "performance" option which is a harder polyurethane than the stock replacement.


The first day of in town driving I noticed that the shifting felt much smoother as in no jerks/jolts felt from inside the car. The shifts happened quicker because now when the power is being sent to the rear end there is no compression, decompression of the bushings before the input is felt. Everything stays in place and the shifts as well as any kind of throttle input just goes right down the line and translates to being felt faster. This includes off the line acceleration, since the bushings are not compressed while stopped, soft and worn out bushings will compress before the acceleration is fully transferred..the stronger bushings just keeps their place allowing the power to be transferred and felt a bit quicker. The rear end also just generally felt way more solid and stable.. if you've done the Figs LCA bushings you'll know what I mean. I discovered manual mode was not acting jerky around town in low rpms or mid range and I even tried to upset it by kind of pressing and releasing the throttle sharply at different rpm ranges in 2nd and 3rd gear. The strength of the new bushings didn't allow the diff to make me feel that bucking feeling thats felt from the drivers seat, the car remained steady when abruptly letting off the gas from the inside the whole time. Since the diff is suspended by these bushings I believe that some road bumps and vibrations caused it to bounce or move around which could be felt in the car, a few places I've noticed less extra movement coming from my rear end as well.


Today I went up to the mountains to get a feel for any changes in handling which there are supposed to be with this upgrade and holy ***** was I surprised. For anyone who doesn't know, my car already has coils, very light weight wheels, every chassis brace available from strut towers to the entire subframe, sway bars, and other superpro bushings to keep it short. My car handles really well but I did still get a bit of initial body roll when entering a corner and when exiting that bit of roll would then level out once I was straight. Today the car felt like what was left of the body roll or twisting feeling was gone.. just gone. Turn ins remained extremely flat, it felt like there was more grip and when exiting the car didn't need to level out because it was already flat so the corner exits were smoother and seemed faster. That overall stable feeling I mentioned earlier was evident here too. Since the throttle inputs no longer are effected by squishy bushings, going on or off the gas in a corner was much smoother as well. A friend was behind me on the drive and when we parked he came up and said, your car didnt roll at all, it looked so flat and planted. I was honestly really surprised how much that aspect changed. I feel like the improvement in handling is a huge amount and that makes me really happy.


This bushing kit doesn't add any NVH, it blends in as if were stock. The install was pricey because its work on the subframe all in all with the parts, install and an alignment I'm in about 1,100 but its so worth it. To sum it up, the car feels more stable and put together, the shifts and throttle inputs feel quicker and smoother reducing in car felt jerkiness by a ton, it improves the handling and grip drastically, and it didn't come at the cost of making anything uncomfortable.

 

These are all great upgrades to improve the car’s handling but if it was feeling sloppy then you want to figure out what was causing that and once it’s resolved it will really feel tight. Did you check the rear suspension knuckles on the outer end of the lower control arms? These are always wear out and make the rear feel sloppy

 

The things I was feeling were all fixed from changing the old worn out diff bushings. The rest of the car is doing good. 130k on them and were all cracked and wrinkled when they came out. I had this mod on my mind for at least a year and I think I read an article or post that confirmed the things I was feeling was from worn out diff bushings so I decided to go for it and happy I did.

 

That's a really "niche" mod. How did you know you wanted to upgrade that part?

 

Everything I've done with the car is to make it drive better/feel more solid/handle better. I know what kind of benefits come with upgrading factory bushings and how fast they can age. When I pulled the LCAs out at 70k they were already bad, now I'm at 130k. Figs has this part on their site and I've been seeing it for a while and I read some descriptions of what it can do and it lined up with what I want. I'm very happy with the outcome. Honestly made me think about refreshing any rubber engine/trans mount bushings also. If superpro made a 4gs master bushing kit I'd be all over it.

 

I'd be up to do this mod as a DIY but what would hold me back is reinstalling everything back. I believe subframe bushing parts need more careful attention to how they are re torque. And also there's no documentation as a guide to follow.

 

Off topic but having seen you work around that area of the car, how is the guibo holding out? Does the GS350 need to change it's guibo because i actually can't find a replacement part for it unless it's a whole shaft assembly...i may be wrong.

 

Thanks so much for sharing this information. I will be purchasing a new drive belt, engine/transmission mounts, and this bushing kit soon. I agree it is a good idea to be proactive about replacing rubber parts.

 

I didnt do the install myself so I cant really give you any specific advice. I do know there are other videos of this install on other makes on youtube, hopefully that can help.

 

I didnt do the work myself but the mechanic also didnt alert me to any other issues while he was working on that area. I'm not familiar with replacement parts for that either, sorry.

 

You're welcome! I like to put the info out there in case anyone else is interested. Which engine and trans mounts are you going with, I was thinking about doing that also.

 

Im going to most likely keep those OEM parts.

 

Same here, by chance do you have part numbers or anything like that? I looked quickly a few times but wasnt sure I found the right things.

 

To my knowledge these are the correct part numbers:
12361-31310 (X2) These should be the left and right mounts.
12371-36280 (X1) This is the transmission mount.

 

Awesome, thanks! I had seen that 2 piece set and thought it was correct but you helped me confirm it. The one you said is the trans mount comes up as "rear transmission mount". This piece, I believe is the main trans mount, Ive compared it to the part that gets commonly upgraded.

12371-31270





Upgraded trans mount to compare