Hi I have this most wonderful transmission in my truck.  I'm trying to learn more about it and this is the best place for that!!!

 

For starters, the truck has just under 100k miles on it. 

 

 

1) FLUID TYPE:  What fluid is best to use (The tag is saying Texaco STF 1874 Chrysler P/N 04874464)

2) FLUID TYPE: How much Fluid does it hold?

3) FLUID : Is there an additive that is advisable?

4) TRANSMISSION COOLER: Is there some sort of manual transmission cooler add-on for the trans that would assist in extending the life of the unit?  I understand there were few of these made and the company that made them is out of business.  Therefor my goal is to make it last as long as humanly possible.

5) How many miles can one expect a clutch to last on the NV5600?  I know the answer is somewhat about how it was driven, but let's say worst and best case scenario so I have some idea.

6) The shifting feels a bit vague to me (not nearly as vague as a Porsche 914, which is fun) but still. I'm wondering if it would be a good idea to replace some high wear parts in the shifter or linkage assembly or if that's just how this system is.  Don't get me wrong, I'm loving it!!!!!  Call me silly I actually like a vehicle that requires more skills to drive that your average driver typically possesses!!!  I have a reputation for driving a manual transmission in a way that makes it last beyond it's expected shelf life.  As some of you know, it's all in the feel.

 

Thanks in advance for spilling a small slice of your vast experience and wisdom on me as this awesome group always does.

 

 

 

 

8 hours ago, leety said:

Was this more or less what influenced you to go with the 50 weight and are you using the Mobil Delvac 50 weight as recommended in the article?

 

No. My transmission rebuild told me he would allow me to use this fluid and warranty my transmission against failures if I did use the fluid. Being I was on the hunt for either 75w-90 synthetic GL-4 (must not be GL-5) this was way too hard to find. Where 50 weight synthetic GL-4 is very common and used in all the bigger Eaton Fuller Transmission on larger over the road trucks. Since my rebuilder had the 50 Weight on hand in Mobil that where I started at. I paid a premium price for that one bucket but still half the price for Mopar Fluid from the dealer. 

 

Next will be even cheaper... (12 dollars a quart)

https://www.napaonline.com/en/p/VAN706035M

 

Basically what I was buying from the dealer was in the range of 25 to 29 dollars a quart. Typically cost me 120 dollars for 1 gallon of Mopar fluid. This was one factor that got me out of the dealer only fluids. The second factor was Castrol quit production of the factory transmission fluid. So this meant that what was left was going up in price as well.

 

But what I'm learning from all this when you strip it all down the NV4500 and NV5600 are both transmissions with steel gears and bearings. We both have carbon fiber syncros. That was the huge scare at first was all the talk about the wrong fluid could wipe out the syncros. (Myth) This isn't true. Actually the problem that I found was the Cummins engine laid out so much torque the gear teeth where popping. So the fluid was designed around thermal protection of the gear teeth. The only thing the syncros require is GL-4 fluids (Protection from yellow metal to prevent syncro damage). The only thing the gear teeth require is a GL-4 Synthetic. 

 

This is another reason I'm not sold on the transmission coolers. Because in my study of probe placement you need it as close to the gears as possible and at the top of the fluid where heat rises. Not at the bottom and the farther from the transmission gears like the Fast coolers. I've used a few different probes and IR guns and measured the fluid in different places. The hottest is the passenger side top. Still, to this day the only time I've every broke over 220*F trans temp was doing a study of gear and grade climb on 110*F day on 7% grade. 4th gear (1:1 direct) is the COOLEST gear to climb grades with I climbed a 7% grade with my 31 foot RV and used 3rd instead of 4th. The just prolonged the heating the fluid which drove it up in temp. Next trip I climbed the very same grade in 4th and barely broke 180-190*F. No coolers. 

 

Like my last trip home from Ontario, OR ranging from 120 to 140*F in 85*F degree weather no issue with temps at all. No fancy coolers, no heater shields, no exhaust wrap. Now since I'm mastering the Quadzilla and getting the EGT's reduced the amount of heat coming down the exhaust pipe in greatly reduced. I struggle to even get 1,000-1,100*F in level 3 climbing a grade with the RV now. 

 

On a flip side now going to ther freezer the coldest temp I remember seeing on my outside temp gauge was -35*F going across New Meadows and heading toward Council. Shift quality was still excellent even in the bitter cold even though the fluid is much thicker than factory 75w-80 which 50 weight is actually 90 weight gear lube. No problems with shift quality. I'll bring up something there is a lot of people that complain about using the wrong fluid typically because they have shift problem already or clutch problems and the fluid aggravates the shifting issue. I've started out with fresh rebuild so I can say without a doubt 50 weight fluid are OK to use for NV4500 so far. Almost to 100k miles and still handshaking. 

 

Ramblings of a Mopar Nut...

Edited June 20, 20186 yr by Mopar1973Man

9 hours ago, Mopar1973Man said:

Hmmm... Funny how the 3rd Gens are using ATF in the manual transmissions.

And then Mercedes, the manufacturer of the G56, told Chrysler that ATF is wrong, and recommends a Syncromesh fluid (or GL-4 as well)

15 minutes ago, trreed said:

And then Mercedes, the manufacturer of the G56, told Chrysler that ATF is wrong, and recommends a Syncromesh fluid (or GL-4 as well)

 

This is my point. There is room to play with fluids. Dodge/Chrysler using one thing and Mercedes stating another. Basically comes down to viscosity and the rating of the lube. Now look back at the Getrag's G360 transmissions again produced by Mercedes. You'll see people didn't hold to the spec set by Dodge they experimented a bit and switch from 5w-30 engine oil to some using GL-4 fluids and some using synthetic 15w-40 engine oil. Notice some people when up in viscosity to keep the oil in contact with the bearings and gear teeth longer when the oil is hotter like during towing?

 

This story continues today like @trreed points out where people are changing lubricants to solve spec problems. In the case of what he points out that Dodge went with ATF+4 because they already use it for the automatics and thin enough to make for smoother shift quality. As trreed points out most are going up in viscosity for better protection. Kind of like myself... After the study work and finding the 50 weight (90 weight gear lube) is actually thicker than the 75w-80. Or in trreed case ATF+4 to syncromech which is thicker. Hmmm... See a trend here?

 

 

 

Edited June 20, 20186 yr by Mopar1973Man

With the G56 it has more to do with gear rollover when switching from a dual mass flywheel to a single mass flywheel.  ATF is too thin to be quiet with SMF.  It doesn't have as much to do with synchro protection.

Still thicker fluid is being used. Still heading back towards GL-4 fluid. Just pointing out that you can experiment some with lubricant and specs are not written in stone. Proved two different cases here where people change lubricant away from factory to improve the characteristics of the transmission. (Chose my words a bit better this time)

46 minutes ago, trreed said:

With the G56 it has more to do with gear rollover when switching from a dual mass flywheel to a single mass flywheel.  ATF is too thin to be quiet with SMF.  It doesn't have as much to do with synchro protection.

 

I just thought about that... My Mobil 50 SAE fluid does not have the gear rollover noise like the old 75w-80 that factory provided. Again thicker fluid...

4 hours ago, Dieselfuture said:

Hey, you're one of us now...

YAY!

2 hours ago, Mopar1973Man said:

 

No. My transmission rebuild told me he would allow me to use this fluid and warranty my transmission against failures if I did use the fluid. Being I was on the hunt for either 75w-90 synthetic GL-4 (must not be GL-5) this was way too hard to find. Where 50 weight synthetic GL-4 is very common and used in all the bigger Eaton Fuller Transmission on larger over the road trucks. Since my rebuilder had the 50 Weight on hand in Mobil that where I started at. I paid a premium price for that one bucket but still half the price for Mopar Fluid from the dealer. 

 

Next will be even cheaper... (12 dollars a quart)

https://www.napaonline.com/en/p/VAN706035M

 

Basically what I was buying from the dealer was in the range of 25 to 29 dollars a quart. Typically cost me 120 dollars for 1 gallon of Mopar fluid. This was one factor that got me out of the dealer only fluids. The second factor was Castrol quit production of the factory transmission fluid. So this meant that what was left was going up in price as well.

 

But what I'm learning from all this when you strip it all down the NV4500 and NV5600 are both transmissions with steel gears and bearings. We both have carbon fiber syncros. That was the huge scare at first was all the talk about the wrong fluid could wipe out the syncros. (Myth) This isn't true. Actually the problem that I found was the Cummins engine laid out so much torque the gear teeth where popping. So the fluid was designed around thermal protection of the gear teeth. The only thing the syncros require is GL-4 fluids (Protection from yellow metal to prevent syncro damage). The only thing the gear teeth require is a GL-4 Synthetic. 

 

This is another reason I'm not sold on the transmission coolers. Because in my study of probe placement you need it as close to the gears as possible and at the top of the fluid where heat rises. Not at the bottom and the farther from the transmission gears like the Fast coolers. I've used a few different probes and IR guns and measured the fluid in different places. The hottest is the passenger side top. Still, to this day the only time I've every broke over 220*F trans temp was doing a study of gear and grade climb on 110*F day on 7% grade. 4th gear (1:1 direct) is the COOLEST gear to climb grades with I climbed a 7% grade with my 31 foot RV and used 3rd instead of 4th. The just prolonged the heating the fluid which drove it up in temp. Next trip I climbed the very same grade in 4th and barely broke 180-190*F. No coolers. 

 

Like my last trip home from Ontario, OR ranging from 120 to 140*F in 85*F degree weather no issue with temps at all. No fancy coolers, no heater shields, no exhaust wrap. Now since I'm mastering the Quadzilla and getting the EGT's reduced the amount of heat coming down the exhaust pipe in greatly reduced. I struggle to even get 1,000-1,100*F in level 3 climbing a grade with the RV now. 

 

On a flip side now going to ther freezer the coldest temp I remember seeing on my outside temp gauge was -35*F going across New Meadows and heading toward Council. Shift quality was still excellent even in the bitter cold even though the fluid is much thicker than factory 75w-80 which 50 weight is actually 90 weight gear lube. No problems with shift quality. I'll bring up something there is a lot of people that complain about using the wrong fluid typically because they have shift problem already or clutch problems and the fluid aggravates the shifting issue. I've started out with fresh rebuild so I can say without a doubt 50 weight fluid are OK to use for NV4500 so far. Almost to 100k miles and still handshaking. 

 

Ramblings of a Mopar Nut...

Fun ramblings, very informative!

So based on @Mopar1973Man's basic requirements:

 

Fluid must be GL-4

Fluid must be Synthetic

 

How about this stuff?

 

https://www.ravenol.de/en/products/usage/d/Product/show/p/ravenol-motogear-sae-10w-40-gl-4.html

We have talked about fluids for three different transmissions, none of which were the original transmission in question. There are synchronizer differences between Mike’s NV4500 and your NV5600 that dictate the different fluid requirements. Also, Mike had a shop tell him that they would willingly warranty any damage caused by their recommendation of using a known wrong fluid. Sure it worked, but Mike’s scenario is a one-off situation.

Based on that, I caution trying to find a replacement fluid for the NV5600. As @dripley has said, OEM parts are no longer made, and most on the market are cheap knockoffs. There are only a handful of people who rebuild these transmissions correctly, and they charge around $4600 for a stock rebuild, and you gotta ship the trans as freight to them. Depending on which carrier you use and the distance, there’s another 500-1000 each way. Why play with fire on a rare transmission trying to find a different fluid when pennzoil synchromesh is available at chain auto parts stores for $8.49/quart? It’s just not worth it. 

Edited June 20, 20186 yr by trreed

@Mopar1973Man can you ask your rebuilder on what he thinks about using your fluid in nv5600, unless he doesn't deal with them. Be curious to know. 

18 minutes ago, trreed said:

We have talked about fluids for three different transmissions, none of which were the original transmission in question. There are synchronizer differences between Mike’s NV4500 and your NV5600 that dictate the different fluid requirements. Also, Mike had a shop tell him that they would willingly warranty any damage caused by their recommendation of using a known wrong fluid. Sure it worked, but Mike’s scenario is a one-off situation.

Based on that, I caution trying to find a replacement fluid for the NV5600. As @dripley has said, OEM parts are no longer made, and most on the market are cheap knockoffs. There are only a handful of people who rebuild these transmissions correctly, and they charge around $4600 for a stock rebuild, and you gotta ship the trans as freight to them. Depending on which carrier you use and the distance, there’s another 500-1000 each way. Why play with fire on a rare transmission trying to find a different fluid when pennzoil synchromesh is available at chain auto parts stores for $8.49/quart? It’s just not worth it. 

And that my friend is why I decided to go Pennzoil Synchromesh, until I'm very convinced that something else is better.

Amosoil synchromesh or Penzoil synchromesh for the NV-5600... that’s it. 

 

Don’t experiment with a GL-4 in a NV5600.. there are those who have and aren’t happy with the results or damage. 

 

The NV-4500 came with a 75w-85 fluid, so the SAE 50 or a 75w-90 are only marginally thicker. There are several 75w-90 Synthetic options in GL-4 if someone is looking. 

 

The  G-56 is recommend to run a GL-4 as well, from MB. 

26 minutes ago, Dieselfuture said:

@Mopar1973Man can you ask your rebuilder on what he thinks about using your fluid in nv5600, unless he doesn't deal with them. Be curious to know. 

He said yes you can use the 50 weight in the NV5600 with no issues.

 

Yes, I called my rebuilder Abe at Weller Truck.

Edited June 20, 20186 yr by Mopar1973Man

Can and should are two different things. Yes I can put 80w-90 in my 6 speed (and actually had a shop do that.... idiots) but it doesn’t mean I should. Accelerated wear and poor shift qualities will come around when those brass synchros are eaten away and cold weather hits

Edited June 20, 20186 yr by trreed

6 minutes ago, trreed said:

Can and should are two different things. Yes I can put 80w-90 in my 6 speed (and actually had a shop do that.... idiots) but it doesn’t mean I should. Accelerated wear and poor shift qualities will come around when those brass synchros are eaten away and cold weather hits

Maybe that's why my third gear is a bit stiff when it's cold out, but honestly my 02 Accord shifts like butter comparing to my truck. And I tried running Factory Dodge fluid, Pennzoil and now amsoil with about same results. Maybe po abused it before I got it.

All our transmission should be in the GL-4 class. GL-5 will eat yellow metals and carbon fiber. Do look up for GL ratings lot of good reading.

8 minutes ago, Dieselfuture said:

Maybe that's why my third gear is a bit stiff when it's cold out, but honestly my 02 Accord shifts like butter comparing to my truck. And I tried running Factory Dodge fluid, Pennzoil and now amsoil with about same results. Maybe po abused it before I got it.

Again unknown past history then trying different fluids typically results with this.

 

 

Yes, but they’re not in the same class. I can’t tell you specifically why the 5600 can’t use a GL-4 fluid, but I can tell you at $4600 per rebuild with almost a 1.5 month wait right now, I’m going to be putting in what’s recommended and not be experimenting. 

Edited June 20, 20186 yr by trreed

4600??? I'm glad Ive got an NV4500 was only 1800 to rebuild. About 4 days to be rebuilt.

Exactly.  And that's on the high side for a quality rebuild.  Prices are so much higher that it's literally not worth it to find an alternative anything for a 5600.

Edited June 20, 20186 yr by trreed

There is no way I will ever pay that much to rebuild mine, I'll buy another one or a different one before I did that

You can buy rebuilds as low $2500 still on Ebay and such if you trust that route. I personally don't. 12 month 12k mile warranty does not make me feel warm and fuzzy inside. Just regular rebuild while not cheap is palatable. But if need much in the way a hard parts it real pricey real quick.

 I lost 4th out of the OE about about 7 years ago and found one out of 02 that had 52k on it for $2500. I have put about 200k on since. Still works good but sure would like to have it gone thru.

@trreed who is that guy out Texas that's supposed so good. Something Stick or another? He seems knowledgeable and had 100k warranty on them IIRC.

Super Stick Transmissions.  His stock 5600 rebuild is $3250 with core, 5 year/100k mile/700 HP warranty.  Also offers modifications to the oil passages for increased shifting speed.  So I was really high on my estimate above.  He also offers a 1000 HP capable 5600, and an over 1000 HP capable unit.

Edited June 20, 20186 yr by trreed