gear lube suggestions ?

[Badvert65]

ok, so it has been a while since I have filled a rear axle with lube. Back in the day, I used 90wt and some sure grip additive. I was at a parts store and I saw that they have gear lube with the additive in it. Does this mean I won't need the Mopar additive? Also, has anyone used any of the synthetic gear lubes (do they need the sure grip additive)?
I am just curious as I am pulling the 2.94 open gear and installing a 3.55 sure grip in my 65 Belvedere. I would only like to do this once.

 

[miller]

Same deal here, Badvert65.

Just me, but have no interest in synthetic anything. Though my rear is a fresh 67/w 3.55 suregrip, I used the lube called for in the service manual, and the additive.

 

[Cranky]

A lot of people say they use synthetic lube with no problems but I've also read that since these were not designed with syn in mind, they should be run with the regular stuff. A buddy experimented with Amsoil in his race car and started with the engine and worked his way back and the car went faster by a few .001's. Thing is that he didn't keep the car for a long period of time so I don't know how it lasted but I do know others that seem to be having good results with it.

 

[nm9stheham]

Use of an additive depends on the Suregrip design & clutches. So if it needed it then, it needs it now, synthetic or not. Can't tell you about the oils with the additive already in it.

I am not making a trite comment here, but if you are not using synthetic, you are missing the boat. I've driven about a million miles in almost 4 decades on it, plus raced many dozens of races in off road/rally use. The reduction of wear, and reduction in oil breakdown, especially in harsh gearbox or axle use, approaches phenomenal.

 

[Badvert65]

Use of an additive depends on the Suregrip design & clutches. So if it needed it then, it needs it now, synthetic or not. Can't tell you about the oils with the additive already in it.

I am not making a trite comment here, but if you are not using synthetic, you are missing the boat. I've driven about a million miles in almost 4 decades on it, plus raced many dozens of races in off road/rally use. The reduction of wear, and reduction in oil breakdown, especially in harsh gearbox or axle use, approaches phenomenal.

That is why I am asking. I understand the benefits of synthetic oils. Just wondering if it was worth using in the rear axle, and if additives were necessary. I have plenty of the additive. I just want to fill the axle once, when I swap the gears.

 

[nm9stheham]

Well, I race in rallies and have put synthetic in every gearbox and axle in recent years. We do a sand rally once in a while in SC, and the first time I ran it, the gearbox had good brand fresh petroleum oil. By the end of the rally, with the constant high power needed to plow through the loose sand, the trannie would not shift. Changed the oil and it was fine. The petroleum oil molecules had literally sheared apart under the heavy gear load, and broken down the gear oil. Synthetic never has that issue in that event. So that was a pretty convincing lesson for me of the very much increased ability of synthetics to stand up to breakdown in any gear use.

Similarly, we recently changed the axle gear oils in a 4WD truck used for towing. The almost complete elimination of axle bearing noise with the new synthetic oil was something that my son and I commented on for weeks; it really was like a new truck quietness.

I have put synthetic recently in our '62 Dart 8.25" rear axle; made it quieter.

 

[Paul_G]

I tried switching to synthetic lube in my sure grip. It was not good. The diff made a lot of chatter when backing up. Switched back to regular lube with additive and the diff was quiet again.

I am a fan of synthetic oils. Running Mobil 1 engine oil and atf +4 trans fluid. For some reason the sure grip didn't like synthetic lube.

 

[nm9stheham]

Had the same issue with synthetics in a limited slip rear axle; jumped and grabbed and chattered all over the place! I then added a separate additive (Ford friction modifier) and it was fine. Your experience was casued by not adding the additives to the synthetic. You fixed that by going to an oil with the additive already in it, not by going away from the synthetic.

Hence, my original comment: if the LSD needs additive to get the right level of gear oil 'slipperiness', it needs it regardless of the gear oil type.

 

[Meep-Meep]

SWEPCO

http://www.swepcolube.com/products/swepco-201-multi-purpose-gear-lube