soft diff bushes?

[notout86]

Originally Posted by Aluma007

do the diff bushing inserts work on the automatics too? for that matter, the trans mount and the subframe ones? I did a long trip and experienced that lash for the first time as I came to a stop light after several hours of highspeed corners and undulating roads...thought I'd broken the car.

Not sure your issue is the same. Go back and see how I tried to describe it.

When I have tried the mod on our auto I will certainly report back but that could be a month away.

[StraightOuttaCanadaEh]

So after complaining about our newly coined "drivetrain lash" with the summer tires, I went and gave the coilovers a couple clicks all around towards the HARD setting, went driving and it immediately felt better. So I gave it a couple more clicks, and it felt even better. So maybe it wasn't drivetrain lash, maybe it was just suspension being too soft with the grippier 18" tires.

EDIT: having gone for a few more drives, I may have exaggerated the improvement. It's noticeably better but still there.

[new2subaru]

I ended up removing the front carrier bushings (tops only) and there is less vibration coming through the chassis. I think it's fine for me now and I still get the connected feeling and some gear whine. Everything is just tamed down a little.

[notout86]

Originally Posted by notout86

I asked Whiteline by email
"We have a 2013 Toyota GTS86 auto with torsen diff. I experience driveline lash sometimes and would like to reduce it without introducing harshness or increasing noise (or at least only slightly.) I do not compete. I am thinking of replacing just one pair of diff bushes rather than all four which seems simple but would like your advice.
ONLY WITH YOUR PERMISSION I will be posting your reply on forums. "



Here's their great reply
"If you are looking for a compromise between reduced driveline lash without too much added stiffness, our differential bushing inserts are a good choice. Part number KDT925 includes polyurethane inserts that fill the voiding of the factory rubber. The kit contains inserts to stiffen the outrigger bushings and the cradle mounted differential bushings. An added benefit to this kit is that it is a somewhat easier install and is a more affordable alternative to complete polyurethane replacements. If you would rather use full polyurethane replacement bushings, the outrigger bushings (KDT923) would most likely be the first to deteriorate and would therefore be the best to immediately replace. They are also the easier to install of the two bushings. If you are looking to do any work on the car’s differential bushings, we recommend replacing the cradle bushings (KDT924) as well if the car is already going to be taken apart and worked on. Feel free to share this information and please reach out if you have any other questions!"

OK. I followed their advice & fitted the "Rear Differential Mount Bushing KDT925" .... the one with the inserts to stiffen the front (i.e. outrigger) and rear (i.e. cradle) bushings.
I got a definite improvement in reducing the issue variously described as "drivetrain lash", "rubber banding" "like a springy tailshaft" etc. and I would rate the improvement as 60% in that regard.

Along with it was an unexpected but welcome feeling of general increased tightness/accuracy as if the car is newer. Mine is on 50,000KM, 5 years old, all paved roads.

I do not notice ANY increase of noise/vibration/harshness.

The inserts are softer than I expected and I think they could be harder and my rating might be 80% then along with no increase of NVH.
For an easy job and $60 I think they are a no brainer and wonder why the OE versions are not firmer. If Whiteline come out with harder I would slip them in to try but then they may chew out the original rubber so what I have may be a necessary compromise.

[new2subaru]

Originally Posted by notout86

OK. I followed their advice & fitted the "Rear Differential Mount Bushing KDT925" .... the one with the inserts to stiffen the front (i.e. outrigger) and rear (i.e. cradle) bushings.
I got a definite improvement in reducing the issue variously described as "drivetrain lash", "rubber banding" "like a springy tailshaft" etc. and I would rate the improvement as 60% in that regard.

Along with it was an unexpected but welcome feeling of general increased tightness/accuracy as if the car is newer. Mine is on 50,000KM, 5 years old, all paved roads.

I do not notice ANY increase of noise/vibration/harshness.

The inserts are softer than I expected and I think they could be harder and my rating might be 80% then along with no increase of NVH.
For an easy job and $60 I think they are a no brainer and wonder why the OE versions are not firmer. If Whiteline come out with harder I would slip them in to try but then they may chew out the original rubber so what I have may be a necessary compromise.

You may want to try the full bushing replacements

http://www.whiteline.com.au/product_..._number=KDT924

I would like to read you review

[StraightOuttaCanadaEh]

So is this what I want?

https://www.ft86motorsports.com/whit...-fr-s-brz.html

It says KDT-922-926, does that mean it includes everything from 922 to 926, or just 922 and 926... so confusing all these parts.

Edit: so according to ft86motorsports, whom I messaged on fb with this question, the diff insert is the KDT925

[notout86]

When purchasing Whiteline "Rear Differential Mount Bushing KDT925" there was no mention if it suited the torsen diff & my car model code was either not listed or concealed in the vague list which I do not know how to decode.
Fear not ..... I clarified with Whiteline and they assured me it does. They are considering re-wording.

[notout86]

Originally Posted by new2subaru

You may want to try the full bushing replacements

http://www.whiteline.com.au/product_..._number=KDT924

I would like to read you review

Yes thanks. I was aware of it from Whiteline's suggestions.
The '924 is worth investigating but the '925 was so simple and proving pretty good, so I am sticking with it. If they give up the ghost then it is the '925s but not only they double the price they would be beyond my DIY capabilities to fit so the labour cost goes on top.

[notout86]

Originally Posted by StraightOuttaCanadaEh

So is this what I want?

https://www.ft86motorsports.com/whit...-fr-s-brz.html

It says KDT-922-926, does that mean it includes everything from 922 to 926, or just 922 and 926... so confusing all these parts.

Edit: so according to ft86motorsports, whom I messaged on fb with this question, the diff insert is the KDT925

The Whiteline person I have been emailing has been very helpful and he's in Toronto (as I see you are).

[notout86]

Originally Posted by notout86

OK. I followed their advice & fitted the "Rear Differential Mount Bushing KDT925" .... the one with the inserts to stiffen the front (i.e. outrigger) and rear (i.e. cradle) bushings.
I got a definite improvement in reducing the issue variously described as "drivetrain lash", "rubber banding" "like a springy tailshaft" etc. and I would rate the improvement as 60% in that regard.

Along with it was an unexpected but welcome feeling of general increased tightness/accuracy as if the car is newer. Mine is on 50,000KM, 5 years old, all paved roads.

I do not notice ANY increase of noise/vibration/harshness.

The inserts are softer than I expected and I think they could be harder and my rating might be 80% then along with no increase of NVH.
For an easy job and $60 I think they are a no brainer and wonder why the OE versions are not firmer. If Whiteline come out with harder I would slip them in to try but then they may chew out the original rubber so what I have may be a necessary compromise.

Further to my report of yesterday, today the wife and I realised that starting off from a standing start is now PERFECTLY 100% smooth. That is the best part of the mod. Even a full on start is as it should be. Note that we have the auto and unless I purposely used only a tiny amount of the gas pedal there was always an uncool lurch.
It was so annoying that I started a thread about it a while back and asked if it was ok to always use SNOW mode as that was the only way to fix. I could not get a definitive answer so just put up with it.

Bottom line, if you have an auto, the Whiteline diff bush mod KDT925 is a $60-$80 no-brainer. Even with a manual trans you can expect a 60% reduction of lurch / springiness if nothing else.

[Turdinator]

I have some experience with this. I have in my car TRD engine and gearbox stiffened mounts, whiteline rear subframe inserts, an exedy HD organic clutch, a PST carbon fibre drive shaft and stock diff bushes. As far as the feeling of driveline lash go, the clutch and drive shaft made the biggest difference. The mount for the stock driveshaft centre bearing is very soft rubber. I can also say with this full compliment of mods the acceleration feel much more direct and instant. I wouldn't say the diff bushes are adding much lash although I will probably upgrade them at some point as they are my weak link now.