Cheap Fix (was rear end juddering...)

hachiroku wrote in news:vfD2k.65$Jj1.14@trndny02:

I would bet if you just added the stuff to the mobil one you would have had the same results. KB

After talking to people in the two groups, and some people around here, I decided it was best to drain the Mobil 1 out and go with the mineral oil.

Not very many people (especially the Toyota tech I call "Supraman") and a guy that races at Lime Rock said the Mobil stuff wasn't very good in LSDs...

Mobil 1 is fine. You just have to add the limited slip additive. That is what it's for.

--scott

But the Mobil 1 was rated for Limited Slip. You'd think there'd be enough additive so it would work!

If Mobil 1 is supposed to be for LSD then it should already have the clutch friction modifiers in it. If you have to buy it separate and add it later, why spend the big bucks for Mobil 1? Why not just use the cheap stuff and add the modifier to it?

I wonder what else synthetic oil is supposed to have in it that Mobil 'forgot'?

Jack

Most gear oils do have the modifiers for internal clutches, but usually not enough for the clutches in a LSD (remember, these oils also get used in manual trannies, too)

After talking to a lot of people, both here and in 'real' life, I decided the Mobil 1 was not the best choice. Nobody seemed to like in in LSDs!

That's not what the auto manufacturers say. Use the additive.

--scott

My Linux Box is named 'kludge', since that's what it is.

Not a lot of people are familiar with the term...

Mobil 1 says on their web site that an additive may be needed, too.

But Toyota recommends mineral oil...

Actually, no, most don't. That is why it's sold as a separate additive. M1 is a rare exception.

As is pointed out in the third paragraph here;

No, they don't. If they did, you wouldn't want to use them in a manual transmission. Those modifiers will prevent the synchros from working properly.

--scott

Scott, I thought that most manual transmissions used ATF instead of gear lube. Something about plastic gears and cold, stiff lube.

Jack

Hmmm...guess I'd better read the manual for the tC, but the only 5-speed I have that uses ATF is in the Mazda. All the others use MT-5 gear lube.

IIRC, the tC transmission is sealed. I'll have to take a look...it's due for an oil change soon...but not in 100 degree weather!

hachiroku wrote in news:nkE2k.70$Jj1.7@trndny02:

now that is entirely possible, as I have no experience with the mobil

A lot of them do, these days, but there are still a few that use gear lube. And there are a lot of older cars out there too.

I don't like the ATF, in part because if there is a leak, ATF will leak out very, very fast. I had a Laser with a Mitsubishi transmission that seemed to develop leaks right and left, too.

--scott

I was pretty gung-ho on it. I would have left it and tried the LSD oil with it, but if it didn't work, I would have been dumping $14 worth of Mobil 1 *AND* $9 worth of LSD additive!

Just didn't wanna take the chance.

The car is again a joy to drive, corners are nice and smooth and shifting from "R" to "D" doesn't give a bone-jarring *THUD* that makes you think the rear end is about to fall off the car! ;)

That's not the way the "rating" works at all. LSDs ALWAYS require the additive. An oil saying that its LSD compatible just means it contains no additives that will HARM the clutch packs or cones, whichever applies.

Nope, not true.

If you have to buy it separate and

Better pressure tolerance, better viscosity stability, lower coefficient of friction, longer life, lower oxidation rate at high temperatures, etc. etc. I'm not plugging Mobil 1, per se, but thats the advantage that all true synthetic oils have.

Mobil 1 has a good reputation for synthetic engine oils, but Redline oil seems to be the one that has put more time and effort into synthetic gear oils, IMO. They have many different application-specific gear oils, including manual transmission lubricants with modifiers to make sure the syncrhonizers continue to work well. A problem with some GL-5 rated synthetic oils is that all the friction modifiers to protect hypoid gears found in differentials can actually prevent the synchronizers from doing their job.

It was all the additive. You coulda left the expensive stuff in, and it would have been just fine.