Royal purple synchromax in 6 speed

hooperswish · **Posted:** Wed May 23, 2007 10:47 am

I plan on putting royal purple synchromax in the nsg370 6 speed today. My current fluid is a tad notchy, and I would like to smooth it out. I will keep you all posted as to my impressions. This is from the web:
Chrysler NSG370 transmission
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The Chrysler NSG370 is a 6-speed overdrive manual transmission sourced from Mercedes. It is Jeep's first 6-speed manual transmission and Daimler Chrysler America's second after the Dodge Viper T-56.

The NSG370 does not use standard gear oil for lubrication. It uses a 10W30 or automatic transmission fluid weight manual transmission fluid. Common synthetic alternatives to the factory Mopar branded conventional lubricant are Royal Purple's Synchromax and Red Line Oil's MTL. The synthetic alternatives often improve shifting performance while decreasing internal wear and noise.

Gear ratios:
1 2 3 4 5 6 R
4.46 2.61 1.72 1.25 1.00 0.84 4.06

Applications:

* 2005-present Jeep Liberty
* 2005-present Jeep Wrangler
* 2004-2006 Chrysler Crossfire

JJsTJ · **Posted:** Wed May 23, 2007 11:04 am

The Amsoil Full Synthetic Synchromesh Fluid is pretty good stuff too.

Curious, what did you pay for the Royal Purple brand and where did you get it?

sleeve84028 · **Posted:** Wed May 23, 2007 1:24 pm

Sounds like a fun little project!

hooperswish · **Posted:** Wed May 23, 2007 1:32 pm

JJsKJ wrote:

The Amsoil Full Synthetic Synchromesh Fluid is pretty good stuff too.

Curious, what did you pay for the Royal Purple brand and where did you get it?

$9.99 a quart at my local pepboys. 2 quarts and an $8.99 pump = about $30.00 total.
I know your Amsoil stuff is really good, and I might try it down the line.

JJsTJ · **Posted:** Wed May 23, 2007 2:02 pm

hooperswish wrote:

JJsKJ wrote:

The Amsoil Full Synthetic Synchromesh Fluid is pretty good stuff too.

Curious, what did you pay for the Royal Purple brand and where did you get it?

$9.99 a quart at my local pepboys. 2 quarts and an $8.99 pump = about $30.00 total.
I know your Amsoil stuff is really good, and I might try it down the line.

I could have hooked you up for about that price to your door. :wink:

hooperswish · **Posted:** Wed May 23, 2007 3:17 pm

So if you do the tranny fluid switch, it takes a 17mm hex for the drain plug, and a 14mm hex for the fill plug. I went to do it at lunch today, and all I had was the 17! Dang they make it hard. As it was, I had a friend weld a 17mm nut to a 17mm bolt for the drain. Now I have to ask him for another weld job with a 14mm....so my fluid change will have to wait a couple of days...At least I went to undo the fill plug first(always a good idea) or man I would be fluidless and scrambling. You can buy the 14 or 17 hex, but they aint cheep (I am).

k99jk99j · **Posted:** Thu May 24, 2007 8:07 am

i thought syncromesch was the factory fluid fill? not atf. anyone know for sure?

hooperswish · **Posted:** Thu May 24, 2007 8:59 am

k99jk99j wrote:

i thought syncromesch was the factory fluid fill? not atf. anyone know for sure?

The factory fill IS a synchromesh fill, not atf(too thin). I believe it was found to be a 5w30 weight motor oil with modifications made to the fluid in order to protect the soft yellow metals found in the tranny, i.e. copper or brass.
However, the factory stuff is dino, and I want synthetic. But to repeat, do not use atf, too slippery...
If you want to go factory, use pennzoil synchromesh- same stuff as factory-$7.99 qt. at pepboys.

hooperswish · **Posted:** Wed May 30, 2007 8:58 pm

Well, I gotterdone today. I found the hex sockets needed at autozone. Youneed the 14mm and the 17mm. Autozone sells a pack of 3 which includes the 12mm, 14mm and 17mm for $9.99. I also picked up a 3/8 hex socket for $4.99 for the transfer case plugs. (You can buy online as well. beats $20.00 for each socket.)
The tranny does run a little better (it really never did run bad, just a tad notchy). The old fluid looked somewhat cloudy, and the magnet on the drain plug had a fair amount of minute metal particles standing up on it. About what you would expect. Did the fluid really need to be changed at only 8,000 miles? definitely not. The fluid had a lot of life left to it (you would hope with only 8k). But now I stand satisfied that I am running a synthetic.
Next, front and rear diff!!! BTW the dang factory puts everything on so dang tight! I barely got the oil filter off the first oil change. For this job I had to run to sears to get a 15" socket breaker bar(12.99. I have always wanted one anyway). So it's all good now. I will repost if any changes happen in the future with the rp synchromax i.e. gets smoother or worse...

:wink:

hooperswish · **Posted:** Tue Jun 05, 2007 10:12 am

I went on a 200 mile fishing trip through twisting turning slow go mtn. dirt roads, varying hwy. roads, etc. yesterday, and i have to tell you that so far i am really impressed with the rp synchromax. The best word i can use to describe it would have to be "butter." Very impressed. We will see how it holds up, and how it does in cold temps....i will keep you posted next winter...

adamkrz · **Posted:** Tue Jun 05, 2007 5:19 pm

When I did mine I used the Amsoil and it really made it alot more qiuet,Now I have synthetic everywhere except the transfer case,Also when I did my trany fluid at 40k I noticed a fair amount of metal chips on the magnetic plug,It must be from the times I thought I was driving a 6 speed instead of my 5 speed and grinded it into the reverse gear.

Also on my 04 both the drain and fill plugs are 17mm.

Royal purple synchromax in 6 speed

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