Rear differential needed - what would you do? (1 Viewer)

[tdskip]

Just chipping away at things here - time to get the rear differential sorted. The '68 rig came to me with a welded up one, which won't work for my my mixed street and fire road use so I need to replace it. I believe my options are;

1) find good used one
2) ARB new
3) Auburn new
4) Detroit locker new
5) other brand new one

There appears to be a big cost difference between used and new, which isn't a big surprise, but are new ones really needed for my less than extreme expected use?

Thanks!

 

[airon23]

Following because I'll need the same suggestions when I finally get around to it.

 

[tdskip]

@airon23 - I spent some time calling shops and they said the original Toyota ones are tough and can usually be serviced and re-used. Apparently Auburn makes a nice limited slip one but more money of course.

 

[tdskip]

@Lil'John - your ARBs probably cost more than my '68 rig.

I'm not into spending a bunch of money for no functional benefit beyond throwing stickers on the bumper, so I'm leaning towards OEM used but if it isn't that much more having a LSD in the rear wouldn't be a bad thing, right? I know if I lift a wheel in the back the LSD won't do much for me.

 

[tdskip]

But but but @Lil'John I want to be able casually throw out there "yep, she's got a Mr Fusion Mk2" and stuff like that around the camp fire.

(really hoping everyone gets the refence otherwise worried you all might just write me off..."

 

[matzell]

I have had most types, lock right, arb, detroit, grizzly, zip lockers. I have a 82 FJ40 with an Auburn Pro-Series LSD in the rear of it. It works great! Transparent on the road, works great on easier trails where both tires are on the ground. I would not hesitate to install another one. No air lines, compressors, no twitching , no ratcheting or clunking around turns. For what you plan to due, I think this would be a good option. It will be there when you need it.

 

[tdskip]

@matzell - is it transparent on the road (mean usually unnoticeable)?

Thanks for weighing in.

 

[matzell]

@matzell - is it transparent on the road (mean usually unnoticeable)?

Thanks for weighing in.

Yes, you do not feel it on the road. Nice and smooth with no noise. I had a LSD in the rear of a 86 4Runner back in the mid 90's. It was great on the street and good off-road for fire roads up in the mountains. The one in my FJ40 just went up to Anthracite and Rausch Creek off road parks and did great. It is nice to shift gears and not have the rear end twitch. I hated the Lock-Right I had in my daily driver FJ40 back in the day. I was just out of college and it was all I could afford.

 

[matzell]

@Downey is a fan of a LSD as well I think for what you want to do. See if you can find someone nearby and go for a ride with them in a Locked rig on the road.

 

[tdskip]

Thanks gentlemen-very much appreciate the feedback / experiences.

 

[Steamer]

You could always just source a used stock open 3rd in the want ads which would quickly get you going again without chirping tires. Then hang onto that welded up 3rd in case you decide you want a locker and then you could build it up and be ready for another swap with minimal down time.

 

[Tank5]

I have a good late model fj40 stock open third that I would sell for 65.00 if you pay for the shipping. I am New Mexico. I would guess shipping to be around $80-90

 

[Downey]

Another attribute of the LSD's that I had forgotten about; back in the day we provided a new LSD to Mike Falkoski for his Baja race truck. Since he didn't mind grabbing/chirping in the race truck, he merely didn't run LSD fluid/ran regular gear oil. This gave him more of a locked diff/less of an LSD- - -sooooo, you could try different amounts/combinations of posi fluid mixed with standard gear oil to get the amount of grab you want out of an LSD.

 

[Tigerstripe40]

ARB if, for no other reason, WIDE parts distribution.

 

[tdskip]

Thank you for all of the information and, well, just being generous and supportive my getting this rig squared away.

Running a different transmission oil to change the properties of how a LSD works is new to me, interesting.

 

[Drake2]

I used to run open, stock diffs on my first 67 back in the 90's. 35" Swampers, 4" lift, and a rebuilt stock 350 engine. Also had the stock axles and 3 speed trans/transfer case setup. Wheeled it hard in the mud and never broke a single thing. The stock Toyota drivetrain is really well built. I think for your intended use the stock axles and diffs will be fine. Do a basic rebuild on the axle assemblies so you know what you're working with and run em.

 

[pjohnson]

I suggest buying a good used diff and dropping it in. Then drive it around for a while. Take it out and have fun. You might find you don't need anything more.

 

[tdskip]

Thanks @pjohnson

 

[Living in the Past]

Just chipping away at things here - time to get the rear differential sorted. The '68 rig came to me with a welded up one, which won't work for my my mixed street and fire road use so I need to replace it. I believe my options are;

1) find good used one
2) ARB new
3) Auburn new
4) Detroit locker new
5) other brand new one

There appears to be a big cost difference between used and new, which isn't a big surprise, but are new ones really needed for my less than extreme expected use?

Thanks!

Because this is a pre 3/69 it is not as easy to figure change over dates. My 9/67 68 model has coarse spline inner axle shafts. Believe Lock-Rights are you only option for coarse spline axles. Have a Torson also haven't been made in a very long time. If you haven't do so would verify if you have coarse or fine spline axles. If coarse may just want to look for a whole other axle.

 

[tdskip]

@Living in the Past - thanks for the post, can I tell that without pulling them? I have a spare pair of what look to be coarse spline axles, which means basically nothing as to what is in there unless they were removed with the last owner did the build.