RR Diff swap - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Triumphrider · 10-20-2014, 04:55 PM

Any one have any issues with a diff swap? IE: speedo error, Trac control problems?

I have all the typical bolt ons,
UEL headers
Greddy Axle back
Perrin filter
Crawford power blocks
and OFT tuned

I am not going supercharged until the car is no longer a daily driver. So I am thinking of a diff swap to run a bit shorter gearing. My car is Auto so I would just swap diffs with a friend that has a MT.

gramicci101 · 10-20-2014, 05:03 PM

What is the ring and pinion ratio of the auto diff vs. a manual diff?

Are you looking to swap the diff carrier and everything, or just the ring and pinion gears? The entire rear diff assembly would probably be easier.

Do you know how properly set pinion depth or set backlash on a ring gear?

What does your friend with the manual get out of this little exchange?

Reaper · 10-20-2014, 05:08 PM

I don't think there is a difference. If there is I need to swap with an auto now.

Triumphrider · 10-20-2014, 05:12 PM

Well I can buy the ring gear and pinion....about $800 online, or pick up a complete diff on ebay for about $600 and bolt it in. The Auto has quite a bit longer gear ratio's ...5th gear in my auto is the exact same ratio as the MT's 6th gear.

Reaper · 10-20-2014, 05:17 PM

Nope. I just pulled the part numbers. They all have the same rear diff.

gramicci101 · 10-20-2014, 05:18 PM

Quote:

Originally Posted by Triumphrider

Well I can buy the ring gear and pinion....about $800 online, or pick up a complete diff on ebay for about $600 and bolt it in. The Auto has quite a bit longer gear ratio's ...5th gear in my auto is the exact same ratio as the MT's 6th gear.

Those are transmission ratios though. Do you know what the actual diff ratio is?

Reaper · 10-20-2014, 05:18 PM

4.10 for both. Just checked. OP is very confused.

Triumphrider · 10-20-2014, 05:20 PM

I'm pretty sure The rear diff ratios are different, I'll find the article and post back

gramicci101 · 10-20-2014, 05:20 PM

Quote:

Originally Posted by Reaper

4.10 for both. Just checked. OP is very confused.

I wouldn't say very. He's probably looking at the final drive ratio, which takes both pieces into account.

Dipstik-sportech · 10-20-2014, 05:22 PM

Nope. The speedo is taken from the abs sensors so it doesn't affect that. I've been driving mine with the 3.73 rear gear for months, no issues.

Reaper · 10-20-2014, 05:27 PM

How do you like that? I've been thinking the same. Is 300 rear ends are pretty cheap.

Dipstik-sportech · 10-20-2014, 05:31 PM

I love it. The only complaint I have is that at 50mph it's only pulling 2000rpm and my car doesn't really pull at that rpm. They're not cheap lol.

Reaper · 10-20-2014, 05:32 PM

I've seen them for 400$ but I'm not sure if it's the lsd.

Triumphrider · 10-20-2014, 05:33 PM

Quote:

Originally Posted by Reaper

Nope. I just pulled the part numbers. They all have the same rear diff.

You are correct sir, I been looking at final drive ratios....I was wondering why M/T diffs are on ebay for less than a ring and pinion and no one snapping them up haha my mistake. At least I haven't bought one...
Thanks

10-20-2014, 04:55 PM	#1
Triumphrider Senior Member Join Date: Oct 2013 Drives: 2013 Scion FRS in white out Location: Cambridge, Ontario, Canada Posts: 261 Thanks: 141 Thanked 102 Times in 64 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	RR Diff swap Any one have any issues with a diff swap? IE: speedo error, Trac control problems? I have all the typical bolt ons, UEL headers Greddy Axle back Perrin filter Crawford power blocks and OFT tuned I am not going supercharged until the car is no longer a daily driver. So I am thinking of a diff swap to run a bit shorter gearing. My car is Auto so I would just swap diffs with a friend that has a MT.

10-20-2014, 05:08 PM	#3
Reaper in orbe terrum non visi Join Date: Jan 2014 Drives: violent Location: Mountains Posts: 1,747 Thanks: 279 Thanked 762 Times in 446 Posts Mentioned: 62 Post(s) Tagged: 1 Thread(s)	I don't think there is a difference. If there is I need to swap with an auto now. __________________ I have E85 where there isn't E85, that's my secret. http://www.ft86club.com/forums/showt...t=reaper+build

10-20-2014, 05:17 PM	#5
Reaper in orbe terrum non visi Join Date: Jan 2014 Drives: violent Location: Mountains Posts: 1,747 Thanks: 279 Thanked 762 Times in 446 Posts Mentioned: 62 Post(s) Tagged: 1 Thread(s)	Nope. I just pulled the part numbers. They all have the same rear diff. __________________ I have E85 where there isn't E85, that's my secret. http://www.ft86club.com/forums/showt...t=reaper+build

10-20-2014, 05:18 PM	#7
Reaper in orbe terrum non visi Join Date: Jan 2014 Drives: violent Location: Mountains Posts: 1,747 Thanks: 279 Thanked 762 Times in 446 Posts Mentioned: 62 Post(s) Tagged: 1 Thread(s)	4.10 for both. Just checked. OP is very confused. __________________ I have E85 where there isn't E85, that's my secret. http://www.ft86club.com/forums/showt...t=reaper+build

10-20-2014, 05:22 PM	#10
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s) Tagged: 0 Thread(s)	Nope. The speedo is taken from the abs sensors so it doesn't affect that. I've been driving mine with the 3.73 rear gear for months, no issues. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

10-20-2014, 05:03 PM	#2
gramicci101 Off Topic Join Date: Feb 2014 Drives: 2014 Subaru BRZ Limited Location: Vegas, baby! Posts: 4,610 Thanks: 2,369 Thanked 4,243 Times in 2,170 Posts Mentioned: 43 Post(s) Tagged: 3 Thread(s)	What is the ring and pinion ratio of the auto diff vs. a manual diff? Are you looking to swap the diff carrier and everything, or just the ring and pinion gears? The entire rear diff assembly would probably be easier. Do you know how properly set pinion depth or set backlash on a ring gear? What does your friend with the manual get out of this little exchange?

10-20-2014, 05:12 PM	#4
Triumphrider Senior Member Join Date: Oct 2013 Drives: 2013 Scion FRS in white out Location: Cambridge, Ontario, Canada Posts: 261 Thanks: 141 Thanked 102 Times in 64 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Well I can buy the ring gear and pinion....about $800 online, or pick up a complete diff on ebay for about $600 and bolt it in. The Auto has quite a bit longer gear ratio's ...5th gear in my auto is the exact same ratio as the MT's 6th gear.

10-20-2014, 05:20 PM	#8
Triumphrider Senior Member Join Date: Oct 2013 Drives: 2013 Scion FRS in white out Location: Cambridge, Ontario, Canada Posts: 261 Thanks: 141 Thanked 102 Times in 64 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	I'm pretty sure The rear diff ratios are different, I'll find the article and post back

10-20-2014, 05:27 PM	#11
Reaper in orbe terrum non visi Join Date: Jan 2014 Drives: violent Location: Mountains Posts: 1,747 Thanks: 279 Thanked 762 Times in 446 Posts Mentioned: 62 Post(s) Tagged: 1 Thread(s)	How do you like that? I've been thinking the same. Is 300 rear ends are pretty cheap. __________________ I have E85 where there isn't E85, that's my secret. http://www.ft86club.com/forums/showt...t=reaper+build

10-20-2014, 05:31 PM	#12
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s) Tagged: 0 Thread(s)	I love it. The only complaint I have is that at 50mph it's only pulling 2000rpm and my car doesn't really pull at that rpm. They're not cheap lol. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

10-20-2014, 05:32 PM	#13
Reaper in orbe terrum non visi Join Date: Jan 2014 Drives: violent Location: Mountains Posts: 1,747 Thanks: 279 Thanked 762 Times in 446 Posts Mentioned: 62 Post(s) Tagged: 1 Thread(s)	I've seen them for 400$ but I'm not sure if it's the lsd. __________________ I have E85 where there isn't E85, that's my secret. http://www.ft86club.com/forums/showt...t=reaper+build

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