Engine/Transmission (1998.5 - 2002) Towing with NV5600. 5th or 6th gear?

[dward]

I've read a couple of posts where some guys recommend to tow in 5th gear with the 6 sp Man.
Is this do to an overheating problem in the trans or maybe running too low RPM?
I added the FASS coolers and refilled with 8 qts of Penz Synchomesh, will this alleviate any heating issues?
If 5th is better, at what point is it ideal to shift? I would think with a lighter load on flat ground 6th will be fine.
I understand there would be less stress and better cooler running say 2200 RPM in 5th vs 1700-1800 in 6th.
What is everyone one doing and what is best for longevity and mileage?

 

[KATOOM]

The "best" gear to tow in would be best determined using a temperature gauge so you can monitor the fluid temp while towing. But understanding that most people dont have a temp gauge in their manual transmission.....the reasons why you should tow in 5th is because that gear (in the 5600) is 1:1. Meaning no power transmits through the counter shaft, therefore no heat is generated in the fluid by compounding gear ratios. Running direct will always result in lower fluid temps.

But do you "need" to tow in direct is determined by what you're towing and your towing terrain. If whatever you're tugging around is heavy, like at or over the GVWR, or you have taller than OEM tires, or your gear ratio is tall, or you're in more mountainous roads, etc... then you'll probably want to consider 5th. But obviously if whatever you're towing is mild weight then 6th will be fine as long as you're never lugging the engine. And lugging the engine can be identified with a pyro as the EGT's will skyrocket when the RPM's are low for the load.

I have Fastcoolers and a temperature gauge on my 4500 and I tow mostly in 4th gear (1:1 for the 4500). The running temperatures in my transmission will be considerably hotter in 5th than in 4th.

 

[klcammie]

I agree with above post. I have a 5600 and tow a 6k travel trailer from Eastern Ohio. I use sixth in flat to rolling hills. I will down shift when rpm or temps warrant it.

 

[NIsaacs]

Sixth gear is tough in the NV5600, use it. I do question the 8 quarts of oil, even with the coolers that is excessive.

Nick

 

[RustyJC]

Our 2002 Ram 3500 ETH/DEE had a 4.10 axle ratio. That pretty well determined that we towed our (then) 16K GVWR 5th wheel in 6th gear. We never had a problem doing so.

Rusty

 

[RVTRKN]

Anytime your applying pressure on the NV5600 or the G56 you should run in 5th or lower. Some say never tow anything past 5th gear and some never pay attention to the "5th rule of thumb". But the rebuilders of these transmissions do advise not to tow in 6th when applying pressure to the trans when towing. I have installed a true transmission cooler that helps me maintain the oil temperature under 180*, period. I've found fast coolers to be worthless, and they have only allowed me to install temperature sensors and with me tapping them for 3/8 fnpt for the inlet and outlets for my cooler setup. In the very near future, I'll be removing my fast coolers, and installing CNC machined aluminum plates to cover the PTO's that already have the 1/8 fnpt and 3/8 fnpt tapped in.

 

[KATOOM]

Sixth gear is tough in the NV5600, use it. I do question the 8 quarts of oil, even with the coolers that is excessive.

Nick

The issue isnt a gear "strength" issue but rather a fluid temp. Most people have this misnomer that a manual transmission is impervious to damage from heat and towing. But tow heavy in an OD gear ratio and the heat generates fast and can allow the fluid to creep well over the detrimental temperature of 225*.

As for the fluid level.....the 5600 is well known for lubrication issues based on a poor design that limits the amount of fluid which can easily reach the outer bearings. So running that particular transmission 1 to 2 quarts overfilled helps solve this lubrication problem. The Fastcoolers add 1 quart per side too. So the 8 quarts he has in there sounds about perfect.

 

[NIsaacs]

The issue isnt a gear "strength" issue but rather a fluid temp. Most people have this misnomer that a manual transmission is impervious to damage from heat and towing. But tow heavy in an OD gear ratio and the heat generates fast and can allow the fluid to creep well over the detrimental temperature of 225*.

As for the fluid level.....the 5600 is well known for lubrication issues based on a poor design that limits the amount of fluid which can easily reach the outer bearings. So running that particular transmission 1 to 2 quarts overfilled helps solve this lubrication problem. The Fastcoolers add 1 quart per side too. So the 8 quarts he has in there sounds about perfect.

Yes, I am well aware of overdrive being able to create excess heat, as can any of the lower gears in a prolong usage, any time you use the counter shaft it can create heat. However, on the NV5600 with 6th gear in front, next to the input shaft, it is not near as critical as most transmissions that have overdrive to the rear, such as the NV4500 or Getrag. I tow heavy, have extra power and use 6th all the time. I never see temps over 195 and that is on a hot day, 185 is normal. Obviously when I need 5th I use it but I am not afraid of 6th at all.

I use the standard fill (1 Gallon) on my NV5600, 295k miles so far, same on my '91 Getrag 322k miles. If you keep them full and clean there is no need to overfill. Per the internet, they should both be toast by now.....

Nick

 

[KATOOM]

Dont misunderstand my input Nick. If you're aware of the potentials then thats great and kudos for not basing everything on internet garbage. And I'm not stating that not following other methods based factory specs is the "only" way, nor that everyone has to follow internet info over that of basic maintenance either. A lot of how a vehicle runs and lasts is typically based on the owners capability to self diagnose and attend to what that vehicle needs. Thankfully it sounds like you're that kinda guy too.....

As for the gears in the 5600, I may be wrong but I understood 6th to be more in the middle of the counter shaft, not the front. And yes, the 4500 has its 5th gear hanging on the end but thats because the 4500 was initially a 4-speed which was converted to a 5-speed. Thus the 5th gear hanging outside the main housing with bearing support on only one side. Kinda stupid idea but thankfully it works as long as you dont abuse it.

Temperature wise, I guess it depends on the terrain and ambient temps. Because I can maintain towing temps around 175* - 185* as long as the grades arent miles and miles long. Thats in 100*+ summer heat too. But running up a hill that requires downshifting and the temps will start to climb. Typically maxing out around 200* - 210*.

 

[NIsaacs]

Dont misunderstand my input Nick.

As for the gears in the 5600, I may be wrong but I understood 6th to be more in the middle of the counter shaft, not the front. And yes, the 4500 has its 5th gear hanging on the end but thats because the 4500 was initially a 4-speed which was converted to a 5-speed. Thus the 5th gear hanging outside the main housing with bearing support on only one side. Kinda stupid idea but thankfully it works as long as you dont abuse it.

.

I read all your posts, they are always good reading!

Good description of the NV4500. The cantilever affect of the gears outboard of the case and bearings is tough on the gears, as one wants to be forced in and one out due to the angle cut gears, used hard they will fail, Lol.

Here is a pic of the NV5600:

Nick

 

[klcammie]

Thanks for the pix of my transmission. Ito overfill 1-2 quarts and down shift as needed.

 

[KATOOM]

Good picture Nick. I was thinking 6th was where 3rd was but your picture clarified that. Thanks.

 

[NIsaacs]

Thanks for the pix of my transmission.

You are welcome, 360# of steel is good stuff

When I rebuild a transmission they usually look like one or both of these pictures, Lol

The first one is a Getrag 360, the second one is an NV4500.

The early NV5600 transmissions had some issues that seems to dog even the updated version. I blame some of the problems on the Dodge engineers (Gasp) for telling the consumers in the operators manual that the Getrag 360 and NV5600 had a lifetime oil fill and changing was not necessary. I also feel the factory oil fill was too light so I use 15x40 in both.

Nick

 

[KATOOM]

I agree with you that any lubricating fluid called "lifetime" is a highly misleading. There isnt a lubricant that wont need replacing at some point in time.

But yet, in the auto engineers defense (not that I'm defending them), lifetime fluid is based on the running temperatures they calculate that fluid will average while using the vehicle within the factory ratings. Since oxidation isnt something to worry about until approx 180*, they must have assumed that these transmissions were going to run fairly cool throughout their service life. But clearly the problem with that is I dont think too many of us know anyone who conservatively follows the factory tow ratings and/or hasnt increased their trucks HP substantially either. Not many of us have legitimate room for complaining as we ask far more from these trucks than they're originally built for. But we still do.....

 

[AH64ID]

I've never been scared to use 6th when I can.

 

[JKinney]

I tow in 6th all the time and when climbing mountains east of the Mississippi with my 4.10 gears if I got a good head of steam at the base , I just watch the egt and push some fuel. I have changed my transmission fluid many times, there must be 8 quarts in there if it drips out of an upper plate bolt then i figure its good. If I start to slow and cant keep her at 2000 to 2100 then i go to 5th

 

[HHhuntitall]

I've got a fleet of these things, in 2nd and 3rd gens.... There is currently one sitting in the floor I just pulled out of my '97. Yes, I said a 1997 model. It ran 265,000 miles in this truck, behind this motor, almost 200k of it, the engine was capable of 55-60psi boost, depending on ambient temps and my right foot. I usually didn't push it that hard unless it was over 2000 rpm, as torque hammer is hard on just about anything..... The original NV4500 gave up at 189k, and I installed a new engine and transmission, rebuilt my T-case, and put it together. The first transmission looked like NIssacs's. BUT... it made it home.

This one started crying for mercy last year, so I only drove it when I had to have it. I swapped the transmission last week, with a Blumenthal reman, and am waiting on a bushing for the tailhousing on the T-case. Again.

My point is that the NV5600 is very tough. I'd never put that kind of torque through the G56 or G360 for any period of time.... They can't handle it.

And the point in the 6qt fill is that the input bearing never runs dry. 6qts puts the fill line about 1/2" up in the input shaft, keeping it well lubed. Is it overkill? I dunno... maybe. But as I said, I've been running a lot of boost for a long time through this one. And it doesn't have the updated, drilled shafts to improve oiling. But I've kept the oil changed every 50k, tried not to let it torque hammer too hard, and let my foot out of it when I can..... and is it loaded? Only if I'm driving it. Truck weighs around 13,000 with my tools and me in it. Then a trailer with whatever on it. DOT nightmare? Maybe. But it's served me well!! As has my '03 and '04s. The '03 dyno'ed at 379hp with no electronics.... now? Prolly around 425-450. This engine only has around 65k on it, and transmission is at 135k, holding up well. Yep, tough transmission. But it also helps that I try to keep the oil changed, only go the big boost when I have to, and downshift if the rpm falls while loaded. Everyone to their own, but it works for me.

 

[RVTRKN]

My point is that the NV5600 is very tough. I'd never put that kind of torque through the G56 or G360 for any period of time.... They can't handle it.

For the members here that know my opinion of the G56, this statement sums it up very nicely for me. The G56 is only reliable if you stay within stock parameters and Dodges ratings. HHhuntital, what is your opinion of the Blumenthals rebuilt NV5600? Blumenthals is where my NV5600 is going to come from, when it's time to replace my noisy and weak G56.

 

[NIsaacs]

For the members here that know my opinion of the G56, this statement sums it up very nicely for me. The G56 is only reliable if you stay within stock parameters and Dodges ratings. HHhuntital, what is your opinion of the Blumenthals rebuilt NV5600? Blumenthals is where my NV5600 is going to come from, when it's time to replace my noisy and weak G56.

You might be interested in this, if it were a 4x2 I would jump on it for my '91.

http://www.ebay.com/itm/00-15-DODGE...-TRANSMISSION-CONVERSION-265080-/232190648758

Nick

 

[RVTRKN]

Sounds good, but I wonder if it was in gear when it got wrecked, the NV5600 might not even be worth the Core deposit.