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View Full Version : NV4500 Drain Plug Location(or lack of)


Hooter
05-23-2008, 17:07
I've got a '94 K3500 Dually with the 6.5 and granny low 5 speed. Assuming this is the NV4500. Wanting to service it, but can't find a drain plug. Noticed there is a inspection cover on the side. Assuming this is where it drains from? Was hoping to find a plug on the bottom to make sure all the junk would drain out from it as the side cover doesn't look to go to the bottom of the case.
trbankii
05-23-2008, 17:18
The bottom bolt on the inspection cover goes through the case - remove the bolt from one side (or both sides) to drain. :cool:

Hopefully there isn't too much "junk" to drain... When I drained mine to replace the clutch the fluid was pretty clean. As I bought it used, I have no idea how long ago it was changed though...

Make sure that you use the proper Castrol Syntorq LT fluid!
6.5 Detroit Diesel
05-23-2008, 17:55
There should be a square headed plug located passenger side on the bottom middle. Sorry if that sounded weird. I think that it is a 5/8ths to get it off.
trbankii
05-23-2008, 18:17
Really?

Mine has nothing but the inspection plate bolts - looked it up online to make sure...
Hooter
05-23-2008, 18:37
I had planned on using Mobil 1 80/90 gear oil. Did a Google search on it and looked like it should work. What happens if I use this? Seemed like a good GL-4 synthetic gear oil would be OK.
trbankii
05-23-2008, 20:23
You may want to Google "NV4500 Syntorq"

Castrol Syntorq is the only OEM recommended fluid for the NV4500 - GM or Dodge. You'll find people using others (Amsoil and such), but basically the Syntorq was developed for the NV4500.
AKMark
05-24-2008, 07:56
Besides Amsoil and Royal purple synchromesh trans fluids, the Castrol is the only thing you can put in that transmission.

I've seen three offroad vehicles with the NV4500 that have had conventional gear oil installed, and all three didn't run more than 1K before they started having problems. At that point, it was too late and all had to be rebuilt to continue to be used. The worst part was all three were new, and the company they bought from wouldn't warranty, because when they were sent back, the company (Advance adapters) could tell immediately that the wrong fluid had been used.

Get the right stuff, unless it's time for a rebuild anyway.
6.5 Detroit Diesel
05-24-2008, 09:53
Well, that's the plug I pulled to drain it. :eek: Hopefully it wasn't something else. I could take a picture while the tranny is out and put it up.
Hooter
05-24-2008, 20:19
Found some Amsoil locally. Gonna go with that. Thanks for the replys.
HH
05-26-2008, 07:04
Found some Amsoil locally. Gonna go with that. Thanks for the replys.

Make sure it is the API GL-4 rated oil. GL-5 rated oil is not good for the syncros.

My NV4500 had the square plug on the side.
trbankii
05-26-2008, 11:26
Searching a bit more, apparently some of them did come with a drain plug but others you just remove the lowest bolt from either of the inspection/PTO covers.
6.5 Detroit Diesel
05-26-2008, 21:31
I must have one with a drain plug then. Good to know! Any more info on the truck is appreciated.;)
trbankii
05-27-2008, 06:49
Interesting that we both have a '93 - but with different configurations.

I couldn't really find anything that said what the cutoff was or if it was a hit-or-miss type thing as to which had what.
Turbo Al
05-27-2008, 16:25
Some got it some don't both are NV4500's

Al
Hooter
05-29-2008, 05:49
Picked up the Amsoil 75/90 GL-4 gear oil last night and will put it in over the weekend. This stuff seems pretty thin for being a heavier oil. Compared to the 80/90 gear oil I put in the differential, this stuff seems like water. Will see if it improves the shifting over whatever fluid is in the tranny now.
DmaxMaverick
05-29-2008, 07:47
Picked up the Amsoil 75/90 GL-4 gear oil last night and will put it in over the weekend. This stuff seems pretty thin for being a heavier oil. Compared to the 80/90 gear oil I put in the differential, this stuff seems like water. Will see if it improves the shifting over whatever fluid is in the tranny now.

Sounds normal for synthetic multi-viscosity lube oil at room temp. In any case, it will be much less "thin" if you compare it to dino lube when hot, which is the desired performance. I use Amsoil synthetics, and have never had a lube related issue with them.