Engine/Transmission (1994 - 1998) NV4500 cooking itself dry... how come?

[BushWakr - RIP]

I've a friend who drives a 1st Gen and he's running the NV4500.

He simply cannot keep oil in it. When he takes a long trip he always ends up finding the the oil 'burned off'.

Have any of you guys had any experience with this sort of thing, or heard of it and any solution?

He is a DC Cummins mechanic so he has looked at the more obvious possibilities.



Thanks guys!!



Bob.

 

[Sled Puller]

Is he towing heavy?



I have seen several that the factory lube has cooked away, but they towed heavy.

Never seen that in light loads.

 

[redram]

Check to make sure that the transmission is vented. Since this is a non OE installation, the vent plug may have been removed for shipping or installation. An unvented transmission would build up pressure and force the oil out of the front or rear seals. If it is not leaking at the front, rear or PTO plates, the only place left would be the vent or top cover plate.



Good luck.

 

[Matt42]

The "disappearing oil" happened to me with the NV-4500 in a 1998 Chevy K20. The rear seal failed, and the oil pumped itself into the transfer case. This happened in the space of 2,000 miles, since the dealer checked the oil at a regular service.



The result was grim. We ground (literally) to a halt at the top of Lost Trail Pass, truck in Idaho, trailer in Montana.

 

[BushWakr - RIP]

Sled', he does tow pretty heavy at times. It has been worst at those times too, but he still burns it off over a longer time just running to and from work.



Some good thoughts guys, I'm seeing him this weekend I think,. . I'll pas the ideas along.

If anything else comes to mind, please post it.



Thanks again, Bob.

 

[BushWakr - RIP]

Ok, so I'm slow... it seems that whats happening is the oil is being burnt, not burnt away, just burnt.

It does it heavy or empty, but only in 5th gear.



Does this make more sense???



Bob.

 

[redram]

Without starting a war, what type and brand of oil is he using?



Your friend should take a sample of used oil and have it analysed by the manufacturer of the oil so they can tell him if the oil is actually being "burnt". You have to get oil really hot for it to begin to burn, even with an inexpensive gear oil, that would be +375 F.

He may have contamination, such as water or the wrong type of oil which could reduce the oil's ability to lubricate.



5th gear only is not an oil problem, that would be an oil supply problem or a mechanical problem with 5th gear (bad bearing, misalignment, missing a oil drip rail (don't know if an NV 4500 has these), etc)



Oil does not know to lube 1 thru 4 and not 5. it does not have artificial intelligence.