SJ413 diff into Samurai worth doing?

Starts at the flywheel, ends at the hubs, any problems along them lines, ask your questions here.
Post Reply
Ruru19
Got muddy boots
Got muddy boots
Posts: 26
Joined: Sat Aug 10, 2013 4:06 pm

SJ413 diff into Samurai worth doing?

Post by Ruru19 » Fri May 01, 2020 3:25 pm

Hi all, I was questioning putting a SJ413 diff (3.909 ratio) into the samurai (3.727 ratio) this giving a reduction of 4.66% (If I've calculated right) is it worth doing or just silly?

User avatar
ScottieJ
The Boss
The Boss
Posts: 11603
Joined: Tue Apr 15, 2008 12:13 pm
Location: Chippenham, wiltshire

Re: SJ413 diff into Samurai worth doing?

Post by ScottieJ » Fri May 01, 2020 8:12 pm

If you are on larger tyres than stock then yes
Zuki Build

Steady as she goes!

Ruru19
Got muddy boots
Got muddy boots
Posts: 26
Joined: Sat Aug 10, 2013 4:06 pm

Re: SJ413 diff into Samurai worth doing?

Post by Ruru19 » Fri May 01, 2020 9:00 pm

Ok thanks, was thinking on the first part of the build to go with 235/75/15 tyres and a 410 t-case, but eventually will be running 31/10.5/15s with a 4.16 rocklobster liked the idea of the sj413 diffs to make up the size to gearing and put a lockright in the front. Thanks again Scottie.

User avatar
Jordi
Bow down before me
Bow down before me
Posts: 7529
Joined: Sun Nov 29, 2009 2:35 pm
Location: Darlington, Co. Durham

Re: SJ413 diff into Samurai worth doing?

Post by Jordi » Fri May 01, 2020 9:55 pm

I found just a 4.16 t/box and standard diffs was fine on 31s.

If the old diffs are ok and your definitely swapping the t/box i’d leave the standard diffs in.
1988 Samurai - Truck Cab & Tray Back - 1.6 8v & HIF44 - Snorkel - Stack Exhaust - PAS, YJs & 33s - Trussed, Gusseted & Pumpkin Capped Axles - 4.3 R&Ps - 4.16 T/Box - Rear Air Locker - Full Float Back Axle & Discs - RCV Front Shafts - X-Eng Handbrake - Custom Fuel Tank

Ruru19
Got muddy boots
Got muddy boots
Posts: 26
Joined: Sat Aug 10, 2013 4:06 pm

Re: SJ413 diff into Samurai worth doing?

Post by Ruru19 » Fri May 01, 2020 10:10 pm

Ok, as I have a complet set on front and rear axles was going to recondition once the build was done and stick SJ413 diffs in, would mean I can have both to hand to try out, wanted to add a lockright in the front anyway. So seemed a nice option to have.

User avatar
ScottieJ
The Boss
The Boss
Posts: 11603
Joined: Tue Apr 15, 2008 12:13 pm
Location: Chippenham, wiltshire

Re: SJ413 diff into Samurai worth doing?

Post by ScottieJ » Fri May 01, 2020 11:21 pm

410 transfer box on its own is the right correction for 235/75r15 to get you back to pretty much bang on the stock on road ratio. Once the 31s go on dropping the diffs to 3.909 will again take you pretty much back to the original on road gearing, i.e. within 1-2mph of the same rpm to speed in each gear that you would have on stock height tyres with stock gearing.

Personally I would not fit a lock right in the front, it will destroy your turning circle in mud offroad.
Zuki Build

Steady as she goes!

User avatar
mike harris
SCUK is my life
SCUK is my life
Posts: 1827
Joined: Sat Jan 08, 2011 8:30 pm
Location: hascombe Surrey

Re: SJ413 diff into Samurai worth doing?

Post by mike harris » Sat May 02, 2020 5:31 pm

Lock rites !!!

Get it in there !!
Last edited by mike harris on Sat May 02, 2020 5:36 pm, edited 1 time in total.

User avatar
mike harris
SCUK is my life
SCUK is my life
Posts: 1827
Joined: Sat Jan 08, 2011 8:30 pm
Location: hascombe Surrey

Re: SJ413 diff into Samurai worth doing?

Post by mike harris » Sat May 02, 2020 5:34 pm

Get that lock rite in there !!! Take it from my experience, makes the truck so much better Offroad !

Front locker best modification, just behind Subaru Impreza master cylinder !

Fit free wheeling Hubs, turn the axle off for road use.

If you need any help or anything man just ask always happy to help another lock rite lover out !

Post Reply