News:

It appears that the upgrade forces a login and many, many of you have forgotten your passwords and didn't set up any reminders. Contact me directly through helpmelogin@dodgecharger.com and I'll help sort it out.

Main Menu

75W-90 or 75W-140 in my Dana 60?

Started by 70Sbird, August 19, 2019, 01:14:14 PM

Previous topic - Next topic

70Sbird

I just had my 68 Dana 60 bearings replaced and am putting it back into the car this week. The shop that did the bearing replacement recommended 100% Synthetic gear lube, but they didn't have a clear answer on the weight other than to refer to my service manual. I've been doing some Googling and opinions are all over the board, including some pretty heated debates on some truck forums. The 69 Dodge FSM calls for the 80W-90 wt oil with the Sure-Grip additive. I know that was the correct answer 50 years ago, but is there any advantage to going to a 75W-140 over a 75W-90. This is a street car I use for long stretches on the highway and local driving as well in summer months, no racing, towing etc...
Thanks for looking!
Scott

Scott Faulkner

c00nhunterjoe

I run 75/90 in all 3 of mine. 2 are street driven and see 130 mph at the track, the 3rd is track only and sees 155 mph. No failures on any of them.

cdr

When I bought my new Strange S60, they DO NOT recommend synthetic,, they send 85/140 Lucas with their rear ends when you buy one.
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

c00nhunterjoe

Quote from: cdr on August 19, 2019, 04:26:15 PM
When I bought my new Strange S60, they DO NOT recommend synthetic,, they send 85/140 Lucas with their rear ends when you buy one.

Did you get a trak lok or the strac diff?

cdr

Quote from: c00nhunterjoe on August 19, 2019, 08:42:06 PM
Quote from: cdr on August 19, 2019, 04:26:15 PM
When I bought my new Strange S60, they DO NOT recommend synthetic,, they send 85/140 Lucas with their rear ends when you buy one.

Did you get a trak lok or the strac diff?

The S trac
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

c00nhunterjoe

I beleive the helical locking diffs do not react well to full synthetics. We did not run it in the military versions either.

John_Kunkel

Yeah, from their website"

"Gear Lube DO NOT USE SYNTHETIC GEAR OIL Will adversely affect unit operation and void warranty."
Pardon me but my karma just ran over your dogma.

70Sbird

Interesting, but if they are using a "Sure Grip" system that does not play nice with Synthetics I understand. But I'm still curious about my 50 year old unit. I believe I have run synthetic lube in it before with no adverse effects, I'm just trying to do what's best for the axle since I don't want to ever see it out again..... ;)

Scott Faulkner

cdr

Quote from: 70Sbird on August 20, 2019, 03:10:33 PM
Interesting, but if they are using a "Sure Grip" system that does not play nice with Synthetics I understand. But I'm still curious about my 50 year old unit. I believe I have run synthetic lube in it before with no adverse effects, I'm just trying to do what's best for the axle since I don't want to ever see it out again..... ;)

If you had no problem running Syn gear oil, then why did you rplace the bearings ?
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

Birdflu

When servicing a Dana 60 with either the 1st generation Powr-Lok or the later used Trac-Lok units, we solely use 80W-90 GL-5 standard petroleum based gear lube in our shop. The clutch type units generally work better with petroleum based lubricants.

70Sbird

Quote from: cdr on August 20, 2019, 04:34:23 PM
Quote from: 70Sbird on August 20, 2019, 03:10:33 PM
Interesting, but if they are using a "Sure Grip" system that does not play nice with Synthetics I understand. But I'm still curious about my 50 year old unit. I believe I have run synthetic lube in it before with no adverse effects, I'm just trying to do what's best for the axle since I don't want to ever see it out again..... ;)

If you had no problem running Syn gear oil, then why did you rplace the bearings ?

CDR, I replaced the bearings as more of a maintenance or "peace of mind" item. They have been there for 50 years and I have some long (2,000 miles plus) road trips coming up in the next year or two starting this October. I pulled the rear axle to fix a persistent pinon seal leak and to replace the springs. In the last 20 years that I have owned the car, I have changed out the rear gear lube a couple of times, once after I bought it, and then again a few years later to replace the cover gasket. I'll be honest, I don't remember what all I have used but I'm pretty sure the last fill was Mobil 1. The guy who replaced the bearings said they looked good for their age, and he didn't see anything they was near failure, but at least now I know everything is good to go with the axle assembly. I have no problems running Dino oil, synthetic, of any combination of weights. I was just curious if any of the options are better than others.  :popcrn:

Scott Faulkner

John_Kunkel

Since the introduction of synthetics, I have never used anything else in Sure-Grips; but the S-Trac is different.
Pardon me but my karma just ran over your dogma.

c00nhunterjoe

Quote from: John_Kunkel on August 21, 2019, 04:13:52 PM
Since the introduction of synthetics, I have never used anything else in Sure-Grips; but the S-Trac is different.

Agreed. Torsion diffs are the exception.