G56'rs

[Randomrunner12]

So what fluid y'all recommend? I can't justify cost for a trans cooler and setup if for years they haven't added them factory or even made kits for the manuals. I don't tow heavier than 10k ever so heat doesn't really seem to be an issue for me trans wise.

 

[AH64ID]

So what fluid y'all recommend? I can't justify cost for a trans cooler and setup if for years they haven't added them factory or even made kits for the manuals. I don't tow heavier than 10k ever so heat doesn't really seem to be an issue for me trans wise.

It’s not an issue for nearly every G56 owner.

The Amsoil I linked above is a great fluid for the G56, but any quality synthetic GL-4 I 75w-90 should work well.

 

[AH64ID]

I tried the actual MB oil (expensive if it can be found) that MB recommended for the G56, and removed it within a thousand miles. Tried 50/50 mix of the MB oil with Royal Purple syncromesh fluid and with a 50/50 mix with Pennzoil scromesh oil. I finally settled on the Mobil delvac 50wt oil. It by far was the best oil I used. If your going to go to GL-4 75w-90, you better add a cooler. The 50 wt was also to heavy and retains heat, so the 75w-90 would even be worse. I have docummented proof that the G56 runs hot and even hotter with a heavier oil. The testing of temps and shiftability is why I went to a real transmission cooler. When the G56 gets hot, the gears can mesh out of alignment due to the softening of the aluminum. Like I posted, it's in the article writen by Joseph Donnelly.

We have gone over this before, but the SHC-MB was only one of four recommended spec's for the G-56 and it wasn't their all climate recommendation either. The all climate fluid is a simple GL-4 75w-90... which is VERY readily available. I always find so surprising that everyone is hung up on a discontinued fluid that wasn't even the main recommendation from MB. 3/4 specs are a GL-4.. you wasted a lot of money on fluids that aren't recommended by MB.

I've also shown you the fluid spec chart before, a 75w-90 isn't heavier than a 50wt. They are on different scales, crankcase vs gear lube. So the 50wt is a heavier oil when cold and they are similar when hot. So if you over-cool the 50wt it's not going to work nearly as well as a 75w-90 GL-4.

That article is very old, the G-56 is far more proven then you want the TDR to believe. You're mad at it because you spent a ton of money on what you perceived to be an issue, when if fact nearly every G56 owner is oblivious to the article and just drives it. It's been a very good transmission for Dodge/Ram.

 

[JohnM45]

Wasn't the Mopar recommendation to use AT4 fluid? I knew MB had other options but wasn't sure...

GL4 75/90 seems to be a common sense way to go...

 

[AH64ID]

Wasn't the Mopar recommendation to use AT4 fluid? I knew MB had other options but wasn't sure...

GL4 75/90 seems to be a common sense way to go...

Yes that’s the factory fill. Then again the dealership now fills the NV5600 and NV4500 with ATF.... so they really just wanted to reduce their fluids. That and who takes a 05 or older to the dealership anyhow.

Factory fill doesn’t mean proper fill. It only has to work for the warranty period. That being said, I’ll bet the vast majority of G56’s on the road still have ATF in them.

 

[Randomrunner12]

As I typed my earlier response I found your write up on my other post hahaha.

Thanks again everyone.

 

[RVTRKN]

John, you can post all you want, I know my bearings we’re burnt, and it cost me a lot of money. All I was making sure of, was that the trans was in good shape because of the DMF conversion to the SMF. You’ve seen the pictures, and it’s a known issue with the G56 running hot. My trans running with an unloaded truck at 10K GVW would run over 200* and saw as high as 250* with boat in tow at only 15K GCW. Until I developed my cooling system or even had a temperature sensor, I can just imagine what the temperature was at 23K GCW. With my cooling system, I kept the trans below 200* and cycled the temps between 160* to 180*. You can post all you want, it won’t change my temperatures. But now that it’s gone, it’s someone else’s problem. OP get a temperature sensor to at least see what your temps are.

 

[AH64ID]

250° didn’t burn your bearings. Even 300° wouldn’t burn them. I’m sure something was wrong to cause the burning, but well never know what.

Again, lots of folks using them. I’ve never seen anyone else talk about burnt bearings.

IIRC my NV5600 would run close to 200° on the case temp doing 85 on 100° day. I’ve also never seen anyone talk about burned bearings in a NV5600.

Were you out of warranty when you found the burned bearings?

We’re the gears damaged? They should see more heat than the bearings.


But none of that deals with why you still tell people that the MB recommended GL-4 75w-90 will run hotter than Delvac SAE 50.

 

[EZeis]

My 07 2500 had 145k on it running atf and the original clutch and dmf. Still going strong for the guy I sold it to. No magic fluids, no smf, no double or triple clutches. No aftermarket hydros. He pulled the clutch and it looked brand new. He put a new dmf kit in it since he already bought it. Surprised me as I got that clutch hot a few times in some tight spots with heavy 5th wheels.
I drove it like a truck though. I didn't speed shift it or race it. I bought a truck, not a drag car. I do miss that truck. Wish I could of afford to keep it and the new 18 I bought. But I definitely don't miss shifting gears for most of my life. Loving the aisin auto.


Earl

 

[Cummins12V98]

Side question. 2013 stick almost 2,000 rpm at 70 mph. What is the gear ratio?

 

[AH64ID]

Side question. 2013 stick almost 2,000 rpm at 70 mph. What is the gear ratio?

3.42 is just over 1900 and 3.73 is just under 2100... assuming stock tires size.

So if almost 2000 means just under 2000 I would say 3.42’s.

5th at 2000 should be 55 with 3.42’s.

 

[Cummins12V98]

Thanks!

that explains the steel diff cover.

That’s good as he will be doing a lot of highway driving.

 

[RVTRKN]

250° didn’t burn your bearings. Even 300° wouldn’t burn them. I’m sure something was wrong to cause the burning, but well never know what. See pictures posted, I know you've seen them before, but there posted for others that might not have seen them.

Again, lots of folks using them. I’ve never seen anyone else talk about burnt bearings. Who cares, mine were and I took the necessary steps to prevent it again.

IIRC my NV5600 would run close to 200° on the case temp doing 85 on 100° day. I’ve also never seen anyone talk about burned bearings in a NV5600. Apples to oranges, Aluminum vrs cast iron, although I believe your nearing the flash point at 250* to 300* it still wouldn't soften the cast iron, like it would with aluminum.

Were you out of warranty when you found the burned bearings? Ya, that works out well doesn't it, the clutch was waisted by the glitch my truck has had since a dealer update the ECM in 2009. Even when I explained the issue to Sag2 at may madness, his first words were "well you slipped the clutch" ya the clutch slipped itself under the surging power, but climbing a grade at 23K GCW when the engine surged uncontrollably. ( you know the story) So do you think the dealer is going to warranty a slipped clutch at 30K+ miles. So I went to the SMF and DDS clutch, do you think the dealer would warranty that. I had trans inspected by Richard Poels of standard Transmission, the expert that Joseph Donnelly used for his article he wrote up. So I'm supposed to tell him to put it back together so I can try to claim warranty. Its down, and I need it to go to the clutch installer, in Tucson AZ, when I lived in SoCal.

We’re the gears damaged? They should see more heat than the bearings. The bearings were the issue, I didn't see the internals when it was torn down. I was sent pictures that I posted, and was asked if I wanted to replace them. I think its a no brainer to have it done when the trans is already torn down, so thats a mute point. Warranty, I doubt it.


But none of that deals with why you still tell people that the MB recommended GL-4 75w-90 will run hotter than Delvac SAE 50.So what your saying is that the 50wt transmission fluid would work perfectly well in your differentials, I doubt it. So multi viscocity oil works with the lower viscocity number is when cold and when warm the molecules change it to the higher viscocity So 70wt cold, 90wt warm. Let me know how well the "Mobil trans synthetic transmission fluid (not SAE) works out for you in your diffentials.

 

[RVTRKN]

I didn't want to edit the post, looking like I tried to hide anything. I'll apologize for two incorrect statements on the last post after looking up the specs for Delvac 50wt. 1st) It is an SAE oil. 2nd) The flash point is @ 400*. But the oil is still lighter than GL4 75w 90 gear oil. The heavier the oil, the less the heat transfer, meaning the oil will run hotter than the lighter oils. ATF4 has the ability to transfer heat better, but in my opinion, it is to light for a manual transmission.

 

[AH64ID]

But the oil is still lighter than GL4 75w 90 gear oil.

Really? What specs are you looking at?

Here’s the specs on the 2 fluids discussed in this thread.

Amsoil MTG GL-4 75w-90
Viscosity at 100°C.....14.0
Viscosity at 40°C.......80.3

Mobil Delvac SAE 50
Viscosity at 100°C.....17.5
Viscosity at 40°C.......132

Here’s another GL-4 75w-90
Viscosity at 100°C.....15.5
Viscosity at 40°C......86

The range of a 90wt can be slightly thicker or thinner at 100°C than the range of a SAE 50wt, but the ones I’m finding are all thinner. Not to mention they are all MUCH thinner when cold. SAE 50wt is not a thinner fluid than GL-4 75w-90.

Just for fun.

Amsoil ATF...East to find specs
Viscosity at 100°C.....7.5
Viscosity at 40°C.......38.5

Or how about Penzoil Syncromesh
Viscosity at 100°C.....9.1
Viscosity at 40°C.......40.6


ATF isn’t that much thinner than synchromesh either, nowhere near as thin as a lot of people think.

 

[JohnM45]

Any chance anyone looked up which TDR magazine issue has that article that was referenced about the G56? I'm in upstate NY all weekend at my inlaws' and have no internet and only a single bar of intermittent cellphone signal.... i'm dying....i might find enough signal to download the article to my phone if i walk up the road.

 

[AH64ID]

Apples to oranges, Aluminum vrs cast iron, although I believe your nearing the flash point at 250* to 300* it still wouldn't soften the cast iron, like it would with aluminum.

Ah, sure different case materiel. What it means is the NV would hold the heat in more than the G56, as aluminum transfers heat faster. So if heat were a major issue one would think the NV would have been more prone to it.

Please don't tell me you've been confusing fluid readings in Fahrenheit for flash points in Celsius all these years... most temps in specs are °C.

Flash point of the Syncromesh I used is 218°C (424°F).
Flash point of Amsoil ATF is 234°C (453°F).

Nowhere near flash point at even 300°F.

Ya, that works out well doesn't it, the clutch was waisted by the glitch my truck has had since a dealer update the ECM in 2009. Even when I explained the issue to Sag2 at may madness, his first words were "well you slipped the clutch" ya the clutch slipped itself under the surging power, but climbing a grade at 23K GCW when the engine surged uncontrollably. ( you know the story) So do you think the dealer is going to warranty a slipped clutch at 30K+ miles. So I went to the SMF and DDS clutch, do you think the dealer would warranty that. I had trans inspected by Richard Poels of standard Transmission, the expert that Joseph Donnelly used for his article he wrote up. So I'm supposed to tell him to put it back together so I can try to claim warranty. Its down, and I need it to go to the clutch installer, in Tucson AZ, when I lived in SoCal.

Location, Location, Location... sure sucks when it's the wrong one.

We’re the gears damaged? They should see more heat than the bearings. The bearings were the issue, I didn't see the internals when it was torn down. I was sent pictures that I posted, and was asked if I wanted to replace them. I think its a no brainer to have it done when the trans is already torn down, so thats a mute point. Warranty, I doubt it.

Certainly worth replacing while it's apart... the rest of the upgraded I'm not convinced on. Just my point of view.

I've done lots of unnecessary upgrades in the past... I'll admit to them and won't be doing the same "upgrades" on my '18. You live and learn. If all we did was read articles and forum blogs about trucks and failures we'd never stop modding or changing things, when in reality most the talk is about very small percentage stuff not major common issues.

So what your saying is that the 50wt transmission fluid would work perfectly well in your differentials, I doubt it. So multi viscocity oil works with the lower viscocity number is when cold and when warm the molecules change it to the higher viscocity So 70wt cold, 90wt warm. Let me know how well the "Mobil trans synthetic transmission fluid (not SAE) works out for you in your diffentials.

How and where did you get the idea to dump it in diffs?

No, what I am saying is that MB recommended 4 different fluid specs for the G56. All 4 are rated for manual transmission use, just as any GL-4 75w-90 would be. Everyone gets hung up on the Mobil Delvac SHC, maybe because it's no longer made but it wasn't the only option.. why ignore the rest of the specs??

Our differentials take a GL-5 fluid... so who is talking apples to oranges?! No one has mentioned putting GL-5 fluids in the G56, only the MB spec'd GL-4.

 

[EDankievitch]

I used my G56 hard. I had 137k miles on my original cutch. I tried all the lubes talked about on here. The one that I found to work best year round was Pensoil synchromesh . ATF seemed to be a bit thin and I always felt when the unit gothot it just didn’t feel right. The 75-90 was way too thick. I couldn’t get it to shift at all when it was below freezing unless I put the transfer case in neutral and let the transmission run if gear a few min. My day starts at 0400 I can’t have my truck idle in the drive for 5 min the neighbors will shoot me. Synchromesh worked very well. Well over 150 kin the unit towing and whatever else it was asked to do. My only mistake was installing way more clutch than I needed. The cofe clutch would get very grabby in the humid climate I live in. The power of the Cummins I never had to ease into or slip the clutch . It would grab an go. Al good until you try to back a trailer up a hill and need the clutch to slip some. Never was an issue with the factory one.
I had really good service out of it and would love to have one in my 13 rather than the slush box it came with.The RFE68 is quite the adventure on hills with a trailer. But that is another story. People way smarter than I built these units. Don’t abuse them. Change your fluid with what meets the spec and enjoy life. If you are burning bearings chances are there is another issue. How you drive? Or an oil passage not drilled properly. Or just not enough fluid. These units benefit from 1 extra qt of lube. . I found it easier to put the passenger side of the truck up on my ramps then do the fluid change. The extra qt goes in easy.

 

[RVTRKN]

If you are burning bearings chances are there is another issue. How you drive? Or an oil passage not drilled properly. Or just not enough fluid. These units benefit from 1 extra qt of lube. .

The burn't bearings was from running ATF at factory level. Only the dealer performed service on my G56 until the SMF was installed. Regardless of what others think, I never treated my G56 harshly, nor the clutch and only towing at 23K GCW was for, maybe a 1000K miles. I know I will never own another one, regardless of lube or how high the level is. I love my new Aisin in my 2019 SRW 3500, I will not do any modifacations or upgrading. After spending $5K+ trying to nurse my G56, I'm done with upgrading.

 

[EZeis]

The burn't bearings was from running ATF at factory level. Only the dealer performed service on my G56 until the SMF was installed. Regardless of what others think, I never treated my G56 harshly, nor the clutch and only towing at 23K GCW was for, maybe a 1000K miles. I know I will never own another one, regardless of lube or how high the level is. I love my new Aisin in my 2019 SRW 3500, I will not do any modifacations or upgrading. After spending $5K+ trying to nurse my G56, I'm done with upgrading.

Dealer underfill it? Dealer did that the first time they serviced mine. Only put in 3 quarts. I caught it on the paperwork. I said wait, that thing holds a lot more than that. The tech used the wrong spec and dumped 3 quarts in and called it full instead of filling it to the fill hole. Fortunately I read the paperwork before signing and paying. So they ran it back in and filled it to the fill hole and left me see that it was to the fill hole. Idiots.


Earl