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.

 

 

 

 

To follow up on this topic, the 5 gallon pail of Red Line MTL 75W80 part # 50206 did not show up in time of the appointment at the garage so I went with the 50% Amsoil MTF/50% SAE 50 Synthetic transmission oil. With the TDS pto covers it takes a little over 2 more quarts of oil to fill the transmission up to the now relocated and raised oil fill hole.

 

My observations were as soon as I got in the truck, I tried shift through some gears with the engine off and it was SOOOOOOOO much easier.  It was like shifting butter.  What surprised me was that the transmission does shift a bit stiff between gears and I just have to take it slow between gears until the oil in the transmission warms up and then it is back to shifting like butter again.  Being that it shifted so much easier with the engine off, I expected it to shift the same engine running but before the whole thing started, I was expecting in the back of my mind that the significantly higher viscosity oil would cause stiff shifts until the oil warmed up.  

 

Overall, I am very satisfied with it.  

 

Now...........I have to decide what to put in the wife's NV5600.  Her truck has about double the miles mine has and the 2nd to 3rd gear shift MUST be done with a momentary hesitation in neutral or the synchronizers bark at you and reject the shift.  I was originally considering the Redline oil for both trucks but I am concerned that the higher viscosity oil may cause a problem synchronizer and shift to become even more of a problem.  On the other hand the higher viscosity oil may help to dampen out the lagging synchronizer and make the shift a bit better.   Any thoughts on this?  

I'll just keep my trap shut... 

Did your trans not shift like butter with the engine off before? Mine always has. 

 

The thicker fluid might grab at the worn syncro's better, and like you said it might not. No way to tell without trying. 

 

SAE50 is thicker than both the Amsoil MTL and cold/cool Redline 75w-90, so there isn't much surprise it needs to warm up. 

On 11/16/2018 at 6:07 PM, LiveOak said:

To follow up on this topic, the 5 gallon pail of Red Line MTL 75W80 part # 50206 did not show up in time of the appointment at the garage so I went with the 50% Amsoil MTF/50% SAE 50 Synthetic transmission oil. With the TDS pto covers it takes a little over 2 more quarts of oil to fill the transmission up to the now relocated and raised oil fill hole.

 

My observations were as soon as I got in the truck, I tried shift through some gears with the engine off and it was SOOOOOOOO much easier.  It was like shifting butter.  What surprised me was that the transmission does shift a bit stiff between gears and I just have to take it slow between gears until the oil in the transmission warms up and then it is back to shifting like butter again.  Being that it shifted so much easier with the engine off, I expected it to shift the same engine running but before the whole thing started, I was expecting in the back of my mind that the significantly higher viscosity oil would cause stiff shifts until the oil warmed up.  

 

Overall, I am very satisfied with it.  

 

Now...........I have to decide what to put in the wife's NV5600.  Her truck has about double the miles mine has and the 2nd to 3rd gear shift MUST be done with a momentary hesitation in neutral or the synchronizers bark at you and reject the shift.  I was originally considering the Redline oil for both trucks but I am concerned that the higher viscosity oil may cause a problem synchronizer and shift to become even more of a problem.  On the other hand the higher viscosity oil may help to dampen out the lagging synchronizer and make the shift a bit better.   Any thoughts on this?  

 

 

You said your wifes is a NV5600 but what trans is yours?

 

nv5600s call for synchromesh manual transmission fluid which has the viscosity of 5w30 motor oil.

 

I can definitely see gear oil building more heat due to higher fluid resistance against the gears. resistance generates heat.

Good synchromesh and fill it up half way up the rotating assembly and call it good. 

5w-30 crankcase is only marginally thinner than 75w-90 gear lube. 

 

SAE 50 is by far the thickest. 

 

20 minutes ago, jigabop said:

 

 

You said your wifes is a NV5600 but what trans is yours?

 

nv5600s call for synchromesh manual transmission fluid which has the viscosity of 5w30 motor oil.

 

I can definitely see gear oil building more heat due to higher fluid resistance against the gears. resistance generates heat.

Good synchromesh and fill it up half way up the rotating assembly and call it good. 

Both her's and my truck have the NV5600.  

 

No.  These transmissions call for lubricant that meets Chrysler MS9224 specifications. All of the above fluids I listed with the exception of the SAE 50 synthetic transmission oil meet this specification as does synchromesh.  I tried synchromesh and it worked OK but not nearly as good as it does now.  I had pto covers that have a raised lubricant level port which allows for about 2.5 extra pints.   

 

1 hour ago, jigabop said:

I can definitely see gear oil building more heat due to higher fluid resistance against the gears. resistance generates heat.

 

Hmmm... Strange I've got trouble with 50 WT lube to get above 100°F on the transmission temp. It like the viscosity of 90 WT gear lube. I've got to be above 50°F outside temp to even break above 100°F trans temp. Without FASS coolers... I've finally made 100k miles on 50 WT oil still going strong no issues to report. Now heading for 200k milestone!

 

Edited November 19, 20186 yr by Mopar1973Man

1 hour ago, Mopar1973Man said:

 

 

Hmmm... Strange I've got trouble with 50 WT lube to get above 100°F on the transmission temp. It like the viscosity of 90 WT gear lube. I've got to be above 50°F outside temp to even break above 100°F trans temp. Without FASS coolers... I've finally made 100k miles on 50 WT oil still going strong no issues to report. Now heading for 200k milestone!

 

 

It looks like your oil temp sender is too high, you might be getting a false reading. And your truck is just too dang clean!

53 minutes ago, NIsaacs said:

 

It looks like your oil temp sender is too high, you might be getting a false reading. And your truck is just too dang clean!

 

Slightly overfilled about a pint. Just checked the fluid today and its still over the top of the sensor. Just got to lightly tip the sensor sample the oil for color and screw the sensor back in and plugin again. Putting the sensor at the bottom will get a false cooler reading since heat rises to the top. This is quote the "hot side" of the transmission which most have heat shields, exhaust blankets and such to keep the transmission cooler. Again mine is cooler from the start without any fast coolers, blankets or heat shields. Now figure that out... All I'm running is that GL-4 50 WT Mobil Transmission Fluid... 

 

@AH64ID had the same comment to and we already dealt with that problem. 

 

57 minutes ago, NIsaacs said:

And your truck is just too dang clean!

 

Like today I crawled the entire truck checking lubes and inspecting brakes and everything the last thing I want is get total covered in oil and dirt. I keep after my leaks and keep the dirt and mud rinsed off. Winter time salt does it task when you leave a ton a mud under the truck. This why I been able to hold the rusting at bay so long!

1 hour ago, Mopar1973Man said:

 

Slightly overfilled about a pint. Just checked the fluid today and its still over the top of the sensor. Just got to lightly tip the sensor sample the oil for color and screw the sensor back in and plugin again. Putting the sensor at the bottom will get a false cooler reading since heat rises to the top. This is quote the "hot side" of the transmission which most have heat shields, exhaust blankets and such to keep the transmission cooler. Again mine is cooler from the start without any fast coolers, blankets or heat shields. Now figure that out... All I'm running is that GL-4 50 WT Mobil Transmission Fluid... 

 

@AH64ID had the same comment to and we already dealt with that problem. 

 

I still think it’s too high thou. The fluid level will likely drop several inches at speed. 

 

I also think the reducing bushings place the probe too far out into the ambient air, which will also reduce the temp readings. 

 

My oil temperature gauge sticks out of the filter head about the same amount and if it didn't have constant fly around it (in the feed for my bypass) I wouldn't trust it's accuracy. Being that your transmission doesn't have pressurized flow around the probe, and the level is likely below the probe at speed I think the reads are low. 

 

The fluid moves enough that the bottom would give a fluid bath temp, which would likely read higher. 

 

Next time you change the fluid you should relocate it to the PTO cover for a final determination. 

 

 

Edited November 20, 20186 yr by AH64ID

24 minutes ago, AH64ID said:

The fluid level will likely drop several inches at speed. 

 

Ummm... Seriously doubt that several inches comment.  Being that from the bottom of the case drain plug to the bottom fill plug is only 6 inches. I've got 7 inches of oil in the case which is over the top of the sensor. 

 

There is oil over the top of the sensor even if I put the gearbox in 5th gear rough road speeds RPM (~1,800) and transfer case in neutral and check it still got oil over the sensor. I've checked this too. 

Edited November 20, 20186 yr by Mopar1973Man

1 minute ago, Mopar1973Man said:

 

Ummm... Seriously doubt that several inches comment.  Being that from the bottom of the case drain plug to the bottom fill plug is only 6 inches. I've got 7 inches of oil in the case which is over the top of the sensor. 

 

There is oil over the top of the sensor even if I put the gearbox in 5th gear rough road speeds RPM (~1,800) and transfer case in neutral and check it still got oil over the sensor. I've checked this too. 

 

Ever seen how far it drops in the diff? Several inches is probably accurate. 

 

Several inches wouldn't surprise me at all, in fact I'd be very surprised if your probe was in the bath at highway speeds. 

I would have to add that even though heat rises I dont think the temp is enough different from top to bottom with the gears stirring the fluid up.

54 minutes ago, dripley said:

I would have to add that even though heat rises I dont think the temp is enough different from top to bottom with the gears stirring the fluid up.

 

I compleatly agree. 

 

The potential issue I see with @Mopar1973Man‘s location is the removal of the probe from direct fluid contact due to its height as well as the reducing bushings.  

 

If the probe were constantly bathed in fluid I bet it would read hotter. 

 

Just the effect of the bushings and airflow will alter the readings. 

 

 

I want to add something too 

Even if sensor is not in oil when moving, coming to a stop should then make the temp go up if sensor got submerged in fluid when stopped. I would think  unless air inside is same temperature then nothing would change. But then again I seen my temp drop 15- 20 degrees or so in matter of seconds less than a minute on a hot day, lagging it in 6th and then downshifting to 5th keeping same speed. So maybe by the time you come to a stop it would change to much to really see what happens at speed vs load. 

Did anyone understood what I'm trying to say or is it just me following my own thoughts 

I get what you’re saying. 

 

The temp when stopped would be lower anyways as there isn’t heat being generated with the gears, and the fluid isn’t moving to pull heat out of the gears/bearings. 

 

34 minutes ago, Dieselfuture said:

Even if sensor is not in oil when moving, coming to a stop should then make the temp go up if sensor got submerged in fluid when stopped.

 

If the operator shifts the transmission into neutral and takes his foot off of the clutch pedal (as he should) when he brings the truck to a stop, then the transmission input shaft and all the gears and bearings on the counter shaft would still be turning, albeit everything would be turning at a  much slower speed and there would be no load on the gears and bearings.  However, there still would be plenty of splashing going on so I would think that the oil level would be quite a bit  lower than it would be if the engine was shut down. 

 

Since friction from loaded bearings and gears would generate heat, it stands to reason that heat would be conducted to the oil as the oil flows around the bearings and gears.  So it seems to me that you would want that sensor immersed in the oil that is returning and collecting in the lower part of the transmission.

 

I think it would be worth some trial runs with the sensor in different locations.  Just my two cents.

 

52 minutes ago, AH64ID said:

The temp when stopped would be lower anyways as there isn’t heat being generated with the gears, and the fluid isn’t moving to pull heat out of the gears/bearings

 

I agree.  For example,  if you had been pulling a load at highway speeds for awhile and then you decided to stop and get some fuel, by the time you arrived at the service station, the transmission would have cooled considerably because of the greatly reduced load.

 

- John

Going back to another life as a UH-60 Maintenance Test Pilot, if I recall from my rusty and faltering memory, the chip detector and the temperature sensors were mounted on the bottom of the main transmission.  Perhaps this may have been a function of accessibility and maintenance design but I guess the point I am making is that the oil is being circulated repeatedly throughout the transmission performing its primary lubrication purpose but also its secondary purpose of carrying thermal energy (heat) to via main module pump to the transmission oil cooler would carry and distribute the main transmission thermal load throughout the oil circulation path.  I am sure the indicated temperature would vary depending upon the location on the transmission it is mounted but probably not enough to matter.  

 

In Mike's case with his NV4500, even if the temperature probe was not in the oil bath/sumped oil, so much would be slung by the main gear shaft throughout the transmission case, I would suspect the temperature throughout the transmission would be reasonably consistent and not vary enough to make that much of a difference.

 

Anyhow........this comment should make things clear as mud now! LOL!  

  

watch all of these in this series. very very enlightening.

 

 

 

9 hours ago, AH64ID said:

 

I compleatly agree. 

 

The potential issue I see with @Mopar1973Man‘s location is the removal of the probe from direct fluid contact due to its height as well as the reducing bushings.  

 

If the probe were constantly bathed in fluid I bet it would read hotter. 

 

Just the effect of the bushings and airflow will alter the readings. 

 

 

 

I agree, however, an analog gauge probably can't read the difference. Pretty sure a digital could but probably not enough to matter.