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Getting more from your LSD: avoid friction modifiers!

04-17-2002, 12:55 PM
I was looking at RedLine's site about to buy some of their LSD friction modifier in the hopes of making my LSD actually WORK worth a damn and noticed they have 75W90 and 75W90-NS oils. The regular 75W90 already has the LSD friction modifiers, the NS doesn't. The NS type says "recommended for manual transmissions and non-limited-slip transaxles that recommend 90 WT oils. Can be used in racing limited-slip units to increase lockup and reduce wheel spin" which I take to read that the friction modifiers actually make the LSD less effective.
Indeed, I just got off the phone with a tech at RedLine. Told him I was running Mobil 1 (which includes the modifier) w/ my LSD and I wasn't satisfied with the performance of the LSD and I was about to buy some of Redline's LSD friction modifier additive thinking it would make the LSD operate better until I read what they said about their NS-type oil.
He agreed and said I was going in the wrong direction. Adding the modifier only makes things more slippery and the clutches would be less likely to grab and kick the LSD into action. His advice was to go with an additive-free oil like their NS-type and add just enough of the additive to get rid of any chatter in turns.

Well, back to the old drawing board!

04-17-2002, 01:21 PM
So Brett, if you were back working again? What would you put in the rear carrier? ARB locker or a limited slip like lock-right? I am unemployeed too and would now have an ARB in the rear if I was still working! :(

04-17-2002, 01:33 PM
I got a job 6 weeks ago, but it pays a LOT less than my last one, so I'm no better off mod-wise :(

Anyway, I want a selectable locker of some sort. Pretty sure I'll be looking at the Eaton by the time I can "afford" it.


04-17-2002, 02:40 PM
Anyone here know enough about diffrentials to determine if not adding the LSD additive would have long term effects on LSD lifespan or performance? This could very well be a great way to make the LSD in the Xterra much more effective?

Brent, are you going to try this? Anyone else?


04-17-2002, 07:41 PM
I would think that could increase wear on the LSD, but I may give it a try in the interest of science. If the LSD dies I have an excuse for a locker! :D I won't use Redline oil though. When I put Redline in my Diff. it sounded like crap when cold.

04-17-2002, 07:58 PM
So do all those oils that say "for use with limited slip" have this friction modifer stuff?

04-17-2002, 11:42 PM
Yes, I will be changing the fluid in my rear diff as soon as possible and putting in only 1-2 oz. of modifier (vs. the 4-5 oz. needed for the ~5% typical dose) and I will be going back to a dino oil.

As far as I can tell, yes, all "LSD-compatible" oils contain the modifiers.


04-18-2002, 09:38 AM
Why not go the route of starting with no additive, then adding to eliminate any chatter? How does it feel to be a guinea pig? :)

04-18-2002, 09:59 AM
Better safe than sorry, and I don't really care to have to open it up again if it does chatter. I'll go with only 1 oz.


04-19-2002, 07:04 PM
OK, just got finished changing the rear diff with Coastal brand 80W90, suitable for "top-off only" in limited-slip applications. I added no friction modifier at all.
So I did a few laps around the neighborhood, cutting hard turns each direction to drive the oil out to the ends of the axle. At no time did I notice any "chatter" from the rear end.
A few minutes later I backed into my spot again and my 3 year old son asked me to "bump" against the curb which always makes him laugh. I bounced off it a couple of times, then figured I could use it to test the LSD. It's a 5" curb with a square corner at the top, just enough to throw off my BFGs if I ease up to it without any momentum.
I wish like hell I had the forethought to try this before I changed the fluid so I could have a direct comparison, but the results appear promising. I backed square to the curb, both tires making contact at the same time, and eased on the throttle. The tires started up a smidge, but as the contact patch left the ground, I got wheelspin from both tires!!! The rear end just walked to the left downhill along the gentle slope of the parking lot.
I then re-aligned with the RR tire making contact well ahead of the LR tire and backed up. This time I had little problem climbing up, so I backed off and tried again but goosed it a tad as the first tire made contact while watching the inside tire as it unweighted. I went right up as I watched the LR tire spin! Same when I approached with the LR tire first, the RR tire would spin when prodded, yet I would still climb right up.
For all I know this is little if any different than I would have seen before I changed the oil, but I'm optimistic.

I'll see if I can't get out tomorrow and do some real-world testing at my little playground. I'll bring the camcorder and set it up on a tripod as I play, if I can't get someone to tag along.


04-20-2002, 07:46 AM
I wanted the sport package because of the rear LSD but couldnt get one at the time I bought my X. What is everyones opinion? Did I miss out?


04-20-2002, 04:37 PM
Brent's results sound promising, but my impressions of the Nissan LSD were not very good. I could rarely tell it was helping any at all. I've since ditched the stock LSD and locked the rear with an ARB. While wheeling my truck with an open diff (without the locker engaged) it feels basically the same as my LSD did in most situations.

If you're really interested in an LSD for your truck and are in good with a local Nissan tech who will hook you up with an install, I'd gladly sell mine for $50 bucks.

By the way, Joe, sent you e-mail about the hitch. Sorry, I got it late today (Saturday) and won't have a chance to meet up with you this weekend.


04-21-2002, 08:34 PM

Thanks for the feedback. If the LSD only performs marginally then I'm not interested at all. How much doe sthe ARB locker setup run?

No problem about Saturday. I just sent the email off in case you were available. Looking forward to the hookup next weekend.


04-21-2002, 10:50 PM
I just filled my diff. with Amsoil today. It has LSD additive already, but I didn't add any extra like I have in the past. Will see if I notice any difference.

Not related at all: While I was at it, I added a 12V powerpoint to my front bumper. Bring on the 12V blenders people! :D

04-22-2002, 06:25 AM
ARBs aren't cheap, all told with the compressor, locker, and install it ended up being about a grand. Right now as far as lockers go, that's really your only choice for the H233B. I've been really happy with mine so far, but ARBs are prone to some problems.

When I come over to drop off my hitch you can take a look at my setup and see what you think.


04-22-2002, 12:56 PM
Well, in my informal testing so far, I'm pleased. I wasn't able to do any off-road testing, but I've done a little testing anyway.

On Saturday I went to an industrial park and did the old "RTI" thing on a loading ramp in 2WD. As soon as one of the rear tires left the ground, it just spun and the other side really didn't push at all. Probably asking too much from that one.
Today in the rain I would break the tires loose when pulling away from intersections/lights and it felt like I was getting more traction than if one tire were spinning, always got a decent push.
Just got back from lunch and I went behind a vacant strip mall to the loading area and did a few peel-outs. I consistently laid down two marks on the gritty/sandy pavement. That's the best test yet.


05-08-2002, 08:21 PM
I think its an ARB for me down the line..... A little pricey for an XTerra though....
I dont expect much from my diff - I just get as much momentum as I can:D

Chuck - Post pics of the 12 volt outlet - Im curious... That could be very cool for powering stuff in a tent etc while still having the truck locked up.

05-08-2002, 08:43 PM
I just bought a 400W power inverter for about $60 from AutoZone. It came with a ligter plug and direct battery clamps. Why buy 12V appliances? Just bring what you got!


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