OK, I had this in the tranny forums but no answers, maybe its dumb idea, what do you guys think about this.

What do you guys think about flushing a NP435 out with Kerosene or deisel fuel before a lube change? I thought about adding one of the above, putting the t-case in neutral and with the engine idling, working it through all the gears, Then drain and filling it with proper lube? Dumb idea or would it be ok?

 

it sounds like it would work. that is what we used to flush out atv motors and axles that were full of sand and water. it might take a few changes to get all the other fluid completely out though.

 

Well I may be completely off base here but unless there's a lot of crud that has gotten into the tranny why would you need to? I just don't see the need unless you have serious sludge/dirt in there in the first place.

 

i don't see the need either, but can't see the harm.

 

No theres not any sign of anything major in the tranny like sludge. I was just thinking it wouldnt be a bad idea since its at least 30 yrs old and probably never been rebuilt, I just didnt want to do somethin that would mess it up. I cleaned the t-case out pretty well with some deisel fuel when I pulled the shift rail out to grind it down for the twin stick, but it wasnt running and I let it set long enough for all the deisel to drain out.
Well since you guys dont think it will hurt it I think i'll try it, I guess the worse that could happen is i'd have to get it rebuilt, thanks, Dave.

 

I guess the only thing I don't like (make that 2 things) is if you can't get ALL the diesel out you'll thin your lube a bit. I'm also not a big fan of spinning bearings that are lubed with diesel rather than gear oil, even if it's only for a minute. Those trannys are pretty tough, if the bearings aren't having issues I wouldn't do anything to it other than drain and refill. Anyway, that's just my .02.

 

> I was just thinking it wouldnt be a bad idea since its at least 30 yrs old
> and probably never been rebuilt

That would tell me the gear lube has been doing the job and I would not fix something that was not broken.

If you are concerned, I would drain the tranny, tip the truck to the pass. side so everything drains completely out and then try to wipe any stray material out with a rag.

 

why are you guys always talking about men wanting to be women and women wantin to be men?

-cutts-

 

This is what I did when I restored my 79 F150 4x4. Granted I already had the cab off so the job was easier. All I did was a visual inspection and fluid change. All the gears looked brand new and the case was spotless so I just added the fluid.
In your case I would remove the tunnel cover and remove the 8 bolts that hold the aluminum top shifter plate on. Pull up gently and the shifter handle will come up as one piece. Open the drain plug and let all the fluid drain. Once the fluid is gone you can inspect all the internal workings. If there isnt any visable gunk or sand I wouldnt bother with the diesel but if it is you could reinstall the plug and fill the case with fuel then take the plug back out and drain. That would clean it pretty good. I personally think these transmissions would work filled with sand and under water like an AK47 but it isnt in my truck.

 

ivanribic, sweet supercab