Hey guys,

I was thinking today and I decided it would be very convenient to have a sight glass in my nv4500 fill plug and my nv241dhd fill plug. Maybe eventually the front and rear diffs as well. Now I know from Mike's thread that the trans fill plug is 3/4 npt. What I don't know is, the t case fill plug size, and diff fill plug size. I'm also wondering if anyone has input on anything special to look for or avoid with a sight glass for this specific application? Also, anyone have a good source for these?

thanks!

Im confused. the fluid level should be flush with the plug hole. I don't think putting in a sight glass will allow you to see anything...?

I overfill all that stuff by as much as I can get squirted in the fill hole, and I filled the trans through the shift tower with and extra qt. I figure with the sight glass, if I can see fluid, it's good. If not, I have to add. 

I didn't know if that was what you were going to do or not. I see your angle now. Yeah that could be useful I think. I think this sight might help...?

 

http://athena.industries/en/prodotto.php/57

Yes something like that would be just the thing. I'm just not sure of the best place to get one. I was looking at this site so far https://m.mscdirect.com/mobileweb/category?catId=12107797&searchTerm= or this

https://m.grainger.com/mobile/product/LUBE-Gage-1U917

I just wasn't sure if there is anything in particular I should look for.

Edited May 18, 20168 yr by leathermaneod

I personally think it should be pretty straight-forward... Someone else may chime in. Here's one from grainger (a place I trust). https://www.grainger.com/product/LUBE-Sight-Plug-Gage-1U924

 

That's about all I got other than let me know how it works. I may do the same.

Lol we must have been posting at the exact same time with the same link. I'll certainly keep the thread updated for you. I do hope someone else chimes in that knows the size on the t case though. Maybe it's the same as the trans. I guess the diffs might even be the same too. Only thing I'm a little concerned about would be getting a brass one. I'm not sure if it would stand up to how tight those plugs sometimes need to be...

Rear diff looks like a 3/4 -14 npt part #03640792

 

Couldn't find a size associated with the t-case plug

Thank you! I'll have to do some more digging on that. I've also still got to find a good source for sight glass plugs. Anyone have any input on what material the plug should be? Does it need to match the case material i.e. steel for the trans and diffs and aluminum for the t case?

Edited May 19, 20168 yr by leathermaneod

Transfer case plugs are steel now.

 

Sweet thanks for the info! Hopefully it's the same size and thread as well. That would really be convenient.

I can see putting a sight glass plug in for the axles or transmission. As for the transfer case it might be hard to get extra fluid in to see it in the sight glass. Little knowledge on sight glasses. Like old Honda motorcycles had them back in the day instead of a dip stick. Now the Honda motorcycle where horrid because about every year or two you had to pull the clutch cover and using a q-tip clean the glass so you could see the oil level. Yamaha got smart and used a wiper that you spun using a screwdriver to clean the glass. So consider the fact that crud will cloud the sight lass over time. Just like pulling the differential cover and everything has coating of the black that just wipes off.

Thanks for the tip and the info! I wonder if a sight glass with a reflector would be better or worse for keeping it clean? I'm having a hard time finding these locally so I'm probably going to have to order off the net. I wanna try my best to get it right the first time.

Nothing will keep it clean it just going to have to be a maintenance thing that when you change fluids you need to pull the sight glass and clean it. So I would say without the reflector...

 

15 hours ago, leathermaneod said:

Thank you! I'll have to do some more digging on that. I've also still got to find a good source for sight glass plugs. Anyone have any input on what material the plug should be? Does it need to match the case material i.e. steel for the trans and diffs and aluminum for the t case?

On the industrial side of things all the sight glasses I've seen are brass screwed into in a steel or aluminum case. 

Thanks for the input! It's looking like I'm going to have to order online after all so I should be able to get whatever material I want. I've called every local place I can think of with no luck. 

The transmission and differentials are regular 3/4" NPT.  But the transfer case is tapered 22x1.5mm.  Not very typical.

 

I installed a sight plug on the transmission as I have it overfilled and use the sight glass as a visual confirmation for the amount of fluid in the transmission as much as its color condition.....because obviously (and as already pointed out by others) the level of the fluid would have to be overfilled otherwise you wouldn't see anything unless you were driving and fluid was sloshing.

 

Important though is that you'll want to make sure the temperature rating of the sight glass you're looking at.  They're not all high temp and some are actually so low of temperature rating that I wouldn't suggest using it because you wouldn't want to chance the sight glass failing.

 

I eventually found a 500*F sight glass in 3/4" NPT, although it didn't come with a reflector, but I wasn't able to find the right thread pitch in a sight glass for the transfer case which also had the correct temperature range.

 

I'll post some pictures as to what I installed on the transmission and the solution to not finding what I wanted for the transfer case tomorrow.

 

Thats one slick setup!

Thank you.

23 hours ago, KATOOM said:

 

I was going to say why not point bottom fitting up more to get hose out of the way, but then realized that you can drain fluid out of it without taking that fitting out.