Hi all, i just changed the fluid in my nv5600 last weekend, i used the redline mtl-90. I drained through the lower pto bolt, and filled through the shifter. Now i got out just a whisker over a gallon milk jug, and filled with 5 full quarts. My problem is, it shifts harder, and grinds more that it did with the old fluid. Is there something i don't understand? It is realy bad for 3rd gear, especially when it is within the first 5 miles. the truck has 188,000 miles, 90% of that is highway. Is there something i did wrong, or should do? I thought the redline was supposed to make it smoother. Thanks for your replies. Jason
P.S. The truck is a 2002 4x4, nv5600, dana 80 rear, 60 front.

 

You may want to do a search on the NV5600. I know the recommended fluids are the Texaco lube sold by the dealer, Penzoil syncromesh, and I think there is one or 2 others that meet the spec for the tranny.
If you put the wrong stuff in, it could be a step backward. The Penzoil is readily avaialbe, not too bad on cost.

 

The "MTL90" is heavier weight oil than just the regular Redline MTL thats probably why your having a harder time shifting. Thicker oil equals better gear protection against wear and shock loading but will also cause harder shifting.

 

OH... there wasn't that option at the auto store, only two to pick from, mtl-90, and regular 75-90 gear oil. i just made sure it was gl4 spec. So, am i going to have trouble, will i have to drain it all out, and replace, or can i drain half and add MTL to it. What is the suggestion before i damage it. Thanks

 

I've heard of guys mixing different weights before, even different types (gear oil and atf for example), but I've never trusted that. I would drain it and fill it with the right stuff. I've heard good things about the Redline MTL in these trannies. I'm running RoyalPurple Syncromax in mine right now. Its not bad, but I think the stock stuff did better.

 

Yeah, thats what i figured. i just didn't want to waste $55.00 for the 5 quarts dumped in. Better then the price for a rebuild i guess. Lesson learned!!! Thanks for the input.

 

$55 is still cheaper than a trans rebuild. I'm running regular Redline MTL in mine with no issues. The only ones I have involve the loose nut behind the wheel.
I think MTL90 is meant to be used in the NV4500.

 

I drained out the Texaco stuff at around 60K and it seemed a little thicker thatn the Redline MTL. After the fluid change it shifted noticably smoother. Although, I have read quite a few posts where guys replaced the MTL with the Amsoil version and thought it shifted even better. I don't have anything to compare it too though.

 

I also ran Redline MTL in my 2001. Had it in there for 40k miles. No problems at all, but didn't notice any real improvements either, except when it was cold.
I ordered my REdline from Jeg's. No one around here carried what I needed.

 

I changed the lube, put the mtl in, and dumped 5 1/2 quarts in. It's at least back to normal, i don't know if it is any better than the stock, but alot better than the mt-90. I can't believe the difference it makes between the two lubes. Thanks for all the input.