I have aluminum flakes in my NV4500 oil looks like metallic paint What can be wrong? What is aluminum in the transmission?

Something in the rear cover failed. The rear cover is aluminum.

Could it be 5th gear nut lose and gear slid back grinding on housing.

No matter what that transmission is coming out and being fully inspected for damage and clean all the debris out of it. Get enough junk in the oil holes for the bearing either will plug the oil holes up and ruin the bearings or enough small debris makes into the bearings and ruins the bearings either way that transmission is coming out to be cleaned up.

Complete disassembled main shaft nut loose-- washer hitting 5th gear syncro fork (aluminum)  replaced nut -shift fork- 5th gear on main shaft

 

Did you upgrade the main shaft too? 

 

IIRC the torque on the 5th gear nut is in the range of 500-600 foot pounds on the upgraded shaft. You might look it up and make sure it torqued properly. Way too many video out there of guys beating the nut back on with a hammer and chisel. For sure not the way to do this job. 

8 hours ago, IBMobile said:

 

Still I don't trust your calibrated torque hammer it doesn't say "Snap-On". Most likely a Harbor Freight and the Calibration is very good.

I changed my fluid for the first time (yes, ever. still was the original 1999 fluid) at ~195-200k miles. Came out looking like metallic gold paint. Figured it would be a little normal for having that much mileage, so I just bought 6 quarts of the Mopar PN for the original stuff and filled it back up. I recently made my own short shift kit, and during that, I noticed the fluid is now a very dark gray, but not very metallic (216k). Probably going to change it again soon, but I don't want to spend $150 either. What fluids are out there (or link to other forums) that are sure not to rip the things apart, aside from the Delvac SAE 50W that's been tested? I don't really beat on it or "speed shift" since the engine is bone stock except for an intake and exhaust.

12 minutes ago, jathanmentzer said:

Delvac SAE 50W that's been tested?

 

Any of the Synthetic 50w SAE GL-4 is fine. I'm closing in on the 100k miles on the Delvac no issues to report as of yet. 

 

Now I know that AMSOil has a flavor of Synthetic Oil for the NV4500 I know @AH64ID would know. 

 

75w-90 gear lube is also fine ONLY if its GL-4. If its GL-5 it will wipe out the carbon fiber syncros. 

Alright, thanks. I knew there was a certain grade or rating that it would have to be, just wasn't sure what. Might check out the AMSOil.

Basically stock was 75w-80 for viscosity and the GL-4 rating. 

 

The 50 SAE I run is more like 90 weight oil. Thicker but no issues. 

 

The big thing is GL-4 rating more than anything. 

1 hour ago, Mopar1973Man said:

 

The big thing is GL-4 rating more than anything. 

What's funny is if you go to get it, almost all sale people will say we have gl5 but it covers all previous ones. 

19 minutes ago, Dieselfuture said:

What's funny is if you go to get it, almost all sale people will say we have gl5 but it covers all previous ones. 

 

That's the problem right there. I ran around forever trying to find 75w-90 without GL-5. 75w-90 GL-4 does not exist around here.

Edited February 20, 20187 yr by Mopar1973Man

23 hours ago, jathanmentzer said:

Alright, thanks. I knew there was a certain grade or rating that it would have to be, just wasn't sure what. Might check out the AMSOil.

 

The Amsoil for the NV4500 is their MTG 75w-90. 

 

https://www.amsoil.com/shop/by-product/transmission-fluid/manual/manual-transmission-and-transaxle-gear-lube-75w-90/?code=MTGQT-EA

 

6 qts would be about 2/3 of what you paid for the OEM stuff. Hit me up with a PM if you're interested.