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Being that your car has BOTH, the STS and the trans mount, could some of the "next level" you feel be due to the combination? Or are you simply disregarding the effects of the mount in your analysis...
I have just the STS (and the MTEC shifter springs) and no, I don't think you need the transmission mount to take advantage of the STS.
I had the Z1 trans mount on for 3 days, and it was wayyyy to much NVH for me.
The rear differential bushings eliminate most of the driveline slop, with virtually no increase to NVH. Getting into and out of the gas has no slop.
Lego is right, you don't need the transmission mount as a component of the STS mod. The only reason I did them together was because at the time it felt like the right thing to do, the cost of each mod fit my budget schedule, and I was piggybacking on my time with the mechanic.
I suspect he's right about the diff bushings, too. Although I also have them, it's difficult to pin-point which mod affects what. If your main diff bushing isn't blown (yet), then get the kit and just replace the sides. It's been theorized that the two smaller bushings have a more dramatic impact on tightening down the drivetrain than the main bushing does. Makes some sense.
Last edited by Rochester; Jun 12, 2017 at 12:06 PM.
I have just the STS (and the MTEC shifter springs) and no, I don't think you need the transmission mount to take advantage of the STS.
I had the Z1 trans mount on for 3 days, and it was wayyyy to much NVH for me.
The rear differential bushings eliminate most of the driveline slop, with virtually no increase to NVH. Getting into and out of the gas has no slop.
I have the diff upgrade kit and whiteline bushings sitting in my garage, with hopes that it will help. I don't think that the trans mount is a required mod, but the opportunity to experience one without installing it on my own car is very appealing.
It's been theorized that the two smaller bushings have a more dramatic impact on tightening down the drivetrain than the main bushing does. Makes some sense.
I agree and I am probably partly responsible for the theory about the 2 smaller rear differential bushings making a slightly larger difference in removing drive line slop compared to the one behind the rear differential. It is a very small difference though.
The transmission mount bushing makes a much larger difference in shifting performance than all of the rear differential bushings combined. In fact, I did not notice any difference in shift quality after installing the rear differential bushings. Logically it should be pretty hard to notice any difference as there are a lot more moving parts between the driveshaft and the rear differential compared to the transmission and the chassis.
I agree and I am probably partly responsible for the theory about the 2 smaller rear differential bushings making a slightly larger difference in removing drive line slop compared to the one behind the rear differential. It is a very small difference though.
The transmission mount bushing makes a much larger difference in shifting performance than all of the rear differential bushings combined. In fact, I did not notice any difference in shift quality after installing the rear differential bushings. Logically it should be pretty hard to notice any difference as there are a lot more moving parts between the driveshaft and the rear differential compared to the transmission and the chassis.
Taken in isolation though, the rear diff bushings make more than a small difference.
I've had the following:
Stock
Z1 trans + stock diff
Stock trans + whiteline diff bushings
The transmission mount eliminates all the slop, and adds a bunch of NVH. I don't think there is much room for improvement, and it sounds like the rear differential bushings do just that.
I find the rear differential bushings remove most of the slop, and add a insignificant amount of NVH.
Let's say you're creeping along in 1st at 3500 and traffic is just about to open up, and somebody abruptly slows, and you close the throttle, but don't brake. Gone is the movement the stock setup had. Getting right back into the throttle, hard, and there is no more windup.
The slop in the driveline was my biggest ongoing complaint with my G. I thought my old Legacy GT with transmission crossmember and rear differential inserts was much tighter. IMO the rear differential bushings (and STS + MTEC springs) has brought the whole drivetrain together.
Taken in isolation though, the rear diff bushings make more than a small difference.
I've had the following:
Stock
Z1 trans + stock diff
Stock trans + whiteline diff bushings
The transmission mount eliminates all the slop, and adds a bunch of NVH. I don't think there is much room for improvement, and it sounds like the rear differential bushings do just that.
I find the rear differential bushings remove most of the slop, and add a insignificant amount of NVH.
Let's say you're creeping along in 1st at 3500 and traffic is just about to open up, and somebody abruptly slows, and you close the throttle, but don't brake. Gone is the movement the stock setup had. Getting right back into the throttle, hard, and there is no more windup.
The slop in the driveline was my biggest ongoing complaint with my G. I thought my old Legacy GT with transmission crossmember and rear differential inserts was much tighter. IMO the rear differential bushings (and STS + MTEC springs) has brought the whole drivetrain together.
I guess I don't get to 3500 rpms in 1st and then lift often enough so I will not have a good basis for comparison. Before the trans mount and rear diff mounts I noticed a big movement (you could even watch the shifter move) when you lifted off the gas at basically any speed in any gear. It actually made it difficult to shift. The trans mount ate up 90% of that slop- it still moves a little. The rear diff bushings may have taken up another 5% or so, but I don't really notice it. I will try to keep an eye on it.
I guess I don't get to 3500 rpms in 1st and then lift often enough
I don't either... I'm quickly into second in traffic and avoid first as often as I can. I think we can all relate to being able to watch the **** move when lifting and/or feel it if holding the ****.
I've never had a car with this much play... at least not that I made note of. My memory is really good, but short.
I was just using it as an example. Fill in your rpm/gear of choice. Results are the same
Oh, I misread your last post. I though you were saying that the rear diff bushings make a big difference in addition to the Z1 trans mount. I just noticed you never had both parts on the car at the same time. I do and I really didn't notice any improvement over the Z1 trans mount when I added the rear diff bushings. Glad to hear that the rear diff bushings on their own do make at least a noticeable difference.
Just installed TWMs short shifter, as somewhat expected based on what I read and watched on YT, I broke the shifter socket cup trying to remove the stock shifter to try to reuse it. I bought a new one and then proceeded to break that installing that on the STS despite the use of a lithium grease. doh.
From what I can, the shifter is still pretty snugly in the cup and after putting everything back together, I do not see any looseness in the shifts, just the awesome of short, crisp, and "clicky" shifts.
Did anyone else have similar struggles or am I muscling it too hard?
Two of the right socket cups teeth cracked during install of the STS. The left one shows teeth missing from taking the old shifter out.