Does anybody have opinions on Lucas 75w-140 synthetic gear oil? 

Don't have one.  I use Valvoline 75w-140 full synthetic gear oil, changed out every 45k miles.  

As long as it meets the specification there is no reason for expensive oils.

 

I've stopped chasing high dollar oils a long time ago when a member @dorkweed went 84,000 miles on a single oil change using Walmart SuperTech engine oil and was doing Blackstone test every 7k miles and continued to keep passing the test with flying colors.

 

I use 80w-90 petroleum in the axles (open diff), 50 SAE trans fluid (syn GL-4), Dextron ATF in the transfer case. I save money this way and 481 k miles later no issues now that fixed all the damage stock 75w-80 did to my transmission. Transfer case doesn't require ATF+4 syn oil so Dextron works just as well. Yeah call me crazy but closing in on 500k miles...

4 minutes ago, Mopar1973Man said:

As long as it meets the specification there is no reason for expensive oils.

 

I've stopped chasing high dollar oils a long time ago when a member @dorkweed went 84,000 miles on a single oil change using Walmart SuperTech engine oil and was doing Blackstone test every 7k miles and continued to keep passing the test with flying colors.

 

I use 80w-90 petroleum in the axles (open diff), 50 SAE trans fluid (syn GL-4), Dextron ATF in the transfer case. I save money this way and 481 k miles later no issues now that fixed all the damage stock 75w-80 did to my transmission. Transfer case doesn't require ATF+4 syn oil so Dextron works just as well. Yeah call me crazy but closing in on 500k miles...

I ended up just getting some AGCO 75w-140 from work. Says it eliminates LSD chatter, so we'll see if I need to add additional Friction modifier. 

 

I run CAT in the engine, but only because I work at a Cat dealer and get it for cheap.

 I like @Mopar1973Manput 50 SAE trans oil in my 5 speed after a recent rebuild. So far I'm happy with it. I do notice it being a bit thick on cold morningmore start the engine (clutch in) and let her run til the oil pressure builds the release the clutch and let the oil in the trans circulate a minute before I take off. It don't take long to notice the oil in the trans has warmed a bit.

1 hour ago, Doubletrouble said:

 I like @Mopar1973Manput 50 SAE trans oil in my 5 speed after a recent rebuild. So far I'm happy with it. I do notice it being a bit thick on cold morningmore start the engine (clutch in) and let her run til the oil pressure builds the release the clutch and let the oil in the trans circulate a minute before I take off. It don't take long to notice the oil in the trans has warmed a bit.

What benefits are you guys seeing by running ATF in your 5 speed? I currently have Valvoline synchromesh in my 5-speed because that's what the builder said it needed for warranty. I've got severe gear in my 241DHD. 

No benefits other than shorter life span and early failures. Too thin when heated to 200°F that fluid will be too thin and the hardfacing of the gears will be lost and gears will start breaking.

 

I changed to 50 SAE trans fluid used in Eaton Fuller 10 speeds and stopping the hard face failures of the gears.

 

If you want I dig up my broken parts to show what happens to using too thin of lube in a transmission. (NV4500).

The atf is for the transfer case 

5 hours ago, Doubletrouble said:

The atf is for the transfer case 

I would be interested to see those parts. Sounds like I may be changing the fluid in my NV 4500 now that it isn't under warranty. 

On 3/29/2024 at 11:03 AM, Mopar1973Man said:

As long as it meets the specification there is no reason for expensive oils.

 

I've stopped chasing high dollar oils a long time ago when a member @dorkweed went 84,000 miles on a single oil change using Walmart SuperTech engine oil and was doing Blackstone test every 7k miles and continued to keep passing the test with flying colors.

 

I use 80w-90 petroleum in the axles (open diff), 50 SAE trans fluid (syn GL-4), Dextron ATF in the transfer case. I save money this way and 481 k miles later no issues now that fixed all the damage stock 75w-80 did to my transmission. Transfer case doesn't require ATF+4 syn oil so Dextron works just as well. Yeah call me crazy but closing in on 500k miles...

I've read different things different places, so I'd like some input. Do you guys overfill your nv4500?

No. But I use Eaton Fuller transmission fluid which is SAE 50 weight which is much thicker that factory fluids and protects way better than the thin factory fluid. When your increasing power to you need thicker trans fluid. No you don't need to over fill. The gears can throw the oil to the bearings just fine.

 This is the carnage from my nv4500 after having the oem oil in it for I assume 187k miles. I bought the truck used so I don't know for sure if it had ever been changed. 

 I rebuilt the trans myself and on @Mopar1973Man's advice I now use the sae 50w in the trans. 

Thanks guys.  I'm due for a fluid change anyway.  I'll be switching to SAE 50 weight. Then to find this damn oil leak. Entire bottom of front half of truck is covered with oil. It's even on the back side of the block below the head. I'm thinking combination of the crankcase breather and possibly vacuum pump needs new seals

 

Edited April 6, 2024Apr 6 by Lund1990

 Definitely do the crank case breather mod. (I believe there is an article on that as well). That cleaned up the front on my engine, also helps to keep my new radiator from getting all oily.