G56 Update

[RVTRKN]

It works great, however you have a NV5600, do you need a cooler like mine? It isn't hard it just takes money. Your 03 radiator with the manual will fit the OEM Auto trans cooler without any issues, but I took the extra mile by installing quick disconnects that the Auto OEM coolers have. It keeps my G56 very cool and was worth every penny. But if I had a NV5600, I wouldn't have done it. You can PM me your info if you like.

 

[STEVEBROOKS]

rvtrkn: I PMd you. Thanks!

Steve

 

[RVTRKN]

OK, here are the part numbers I used for the three main components 1) Oil Cooler ordered from Dorman #1988-05251189 2) Tilton Pump #40-527 (continuous duty pump) 3) Moroso Filter housing #23760 (part number depends on direction of flow)

Disclaimer: I recommend researching the numbers for comfirmation to fit your application, I'm giving the numbers as a reference only. Also, search for the better prices, I found a big difference from one distributor to another. I found Summit Racing to be the best for hose and the AN fittings, as well as customer service.

 

[ewcmr2]

The only advise I can give the G56 truck owner is to install a temperature sensor and drop a gear if it starts to warm up, especially a 3:42 optioned truck. My 3:73's with the AE G56 might have something to do with it running hot, but before my cooler was installed, I was running in sixth with 15K GCVW (boat in signature) going west out of Palm Springs on I10 and recorded 230*. They run hot and as mentioned I have the browned bearings to prove it. Unfortunately I did not have a temperature sensor installed, not until the trans was inspected and the bearings replaced and the SMF installed.

My g56 AD/3.54/20k GCW combo runs @185* in 100* ambient temps. Stranoparts got me the SBC/solid flywheel for @ $1000.
Never dyno'd my truck but cresting Cajon/Grapevine at the speed limit isn't a problem with 36' gooseneck in tow.
Are slightly dis colored bearing a definite sign of imminent failure?

 

[photowrite]

My g56 AD/3.54/20k GCW combo runs @185* in 100* ambient temps. Stranoparts got me the SBC/solid flywheel for @ $1000.
Never dyno'd my truck but cresting Cajon/Grapevine at the speed limit isn't a problem with 36' gooseneck in tow.
Are slightly dis colored bearing a definite sign of imminent failure?

Those sound like very reasonable, and quite low transmission temps...are you running an auxiliary trans oil cooler on your G56?

Regardless, sure seems you are getting plenty of good service/performance from your G56 at a reasonably hefty GCW of 20k.

James

 

[ewcmr2]

No coolers. Pennzoil synchromesh at factory level, maybe filled a little over by parking truck on sloped surface.

Above temp taken last week traveling I-5 in the Central Valley. Level ground, 62mph. Oil pan, trans and diff were all within 10* range.
I wonder if anyone has back-to-back temperature tested one quart overfill vs. factory level?

 

[photowrite]

No coolers. Pennzoil synchromesh at factory level, maybe filled a little over by parking truck on sloped surface.

Above temp taken last week traveling I-5 in the Central Valley. Level ground, 62mph. Oil pan, trans and diff were all within 10* range.
I wonder if anyone has back-to-back temperature tested one quart overfill vs. factory level?

I'm running extra, and a good gearbox oil in my 2014 as well.

Are you running temp sensors in the components (confirming not reading with a temp gun)?

With your 20k load and a speed of 62 mph am I correct to assume you're using direct/5th, not overdrive? If so, surely that helps, but your temp seems low, which helps before the added load of grades.

The ZF-S5 in my '96 F-350 ran very hot in overdrive (230+), cooler in direct, but it didn't have tall enough gearing (4.10:1) to run a reasonable road speed in direct without spinning the engine so fast that the coolant/engine got hot. That's not a problem with my current 3.42:1 gears. I'd prefer 3.73:1, but can live with the 3.42:1.

 

[Regcabguy]

No coolers. Pennzoil synchromesh at factory level, maybe filled a little over by parking truck on sloped surface.

Above temp taken last week traveling I-5 in the Central Valley. Level ground, 62mph. Oil pan, trans and diff were all within 10* range.
I wonder if anyone has back-to-back temperature tested one quart overfill vs. factory level?

I had to go to Delvac after the smf was installed. With Pennsoil synchromesh the trans sounded like it was going to grenade.

 

[RVTRKN]

My g56 AD/3.54/20k GCW combo runs @185* in 100* ambient temps. Stranoparts got me the SBC/solid flywheel for @ $1000.
Never dyno'd my truck but cresting Cajon/Grapevine at the speed limit isn't a problem with 36' gooseneck in tow.
Are slightly dis colored bearing a definite sign of imminent failure?

I'm curious to know how you are measuring your temps. I have suspected for some time that the 6.7 4" down-pipe is raising the temps to our G56's, and is why I wrapped my down pipe. If you look at my pictures, in my previous posts, you'll see how close it comes to my coolers, and see the wrap. Also, if you go to a heavier oil, your temps will raise though, but it sure will be quieter.

 

[ewcmr2]

Temps taken with infrared gun. In my 2nd gen 65mph equals 2000rpm in 6th gear - perfect for pulling a big trailer down the road.

My 12 valves cooler EGT's (1250* max) could be helping as well as a 2nd gen may have more/different airflow under the chassis. My 4" down pipe/remote exhaust brake are similarly close to transmission. It's very close to the bell housing but has some breathing room to the gearbox.
My G56 growls in 1st/2nd near idle but quiets down once the RPM's come up a bit. Or maybe it is noisy and I can't hear it over the rattle of the 12valve!

 

[RVTRKN]

I'll take a infrared reading of my trans next time I get it up to temp, but that could be awhile though, I only drive it weekends, if I need to. I would imagine that there will be a difference between the oil vrs case temps. Also, the infrared gun needs to be as close as possible, that red laser beam if you have it on your gun, is just a reference point and represents the center of the cone that the gun is measuring. The farther away the gun is, the bigger diameter of the cone that it measures and it takes the average temperature within the cone. As an example, if your cone is 4" in diameter and 2" on one side is 70* and the other 2" is 90* it will read out as 80*. So make sure your a couple inches away from it, also shiny surfaces can interfere with the reading. I strongly recommend you install a sensor in the oil. Geno's sells an awesome cooler that attaches to the PTO opening and they come with an 1/8 NPT access for the sensor. I installed two sensors, one on each side, so I see both sides of the transmission temperatures, and I have seen a 5* difference in temps while climbing when at empty weight (10.5K) which allows the trans to get hotter and hotter as I climb. That is why I installed my cooler system and at 23K GCW I can keep my temps below 200*.

 

[ewcmr2]

Understood on the infrared cone. I hold gun 4' from gearbox and take multiple reading to confirm consistent readings.

The first summer after I installed the G56 I stopped often to check temps and never saw anything scary. Now I only occasionally check the trans/diff.
Towing with the G56 for almost 8 years (https://www.turbodieselregister.com/threads/205340-12v-six-speed-swap-speedo?highlight=G56) without a problem makes me think it's up to the job. Hopefully it won't grenade tomorrow!

 

[RVTRKN]

ewcmr2, I'll assume your running heavy most of the miles, and I have a question for you. As research and most rebuilders claim, has indicated about the trans case stretching when towing heavy, what is your average GCW?

That's why a girdle was designed to help in eliminating case stretching which I almost purchased. My theory on stretching, is because the trans can run hot, as I have seen running at 15K GCW with my trans oil temp as high as 250* on a 85* day, that allows the aluminum to soften. Your probably familiar with the stretch of roadway I recorded this temperature on. I was west bound on I-10 starting in Palm Springs with trans temp around 200* after decending Chiriaco pass and when I got to Cabazon/Banning I looked down and saw 250*. This was not the first time, I regularly saw this with boat in tow. I don't have enough data with the 5ver at 23K GCW because I now run a true cooling system, and never had a trans temperature sending unit until my browned bearings were discovered and replaced. I believe that happened towing my 5ver up the south bound Grapevine @ 45mph in 4th at 2800 rpm, but as I have indicated I didn't know trans temp.

I'm glad to hear your trans is doing good.

 

[ewcmr2]

18k to 22.5k depending on what car(s) are in back. My "normal" load is 19k, I rarely drive truck without trailer.

I don't know that I buy all the talk about case stretching and softened aluminum. If an old VW bug cylinder head can hold together approaching 400* a transmission at 250* doesn't sound so bad. Iron/steel shrinks with repeated heat cycles, is aluminum the opposite, it grows?
Maybe somewhere along the inter-web stretching and thermal expansion got mixed up and became the same thing? Thermal expansion is surely a bigger concern for an aluminum case, but thermal expansion is a known quantity and the G56 designers must have taken case expansion into account when setting bearing tolerances.

The Pennzoils site says Syncromesh is good to 150c (302*f) When your bearings browned did your transmission still have ATF in it?

 

[ewcmr2]

ATF really doesn't like high temps. Quote below from Googled ATF failure temperature...

"Most ATF can withstand normal operating temperatures of around 200 degrees F for tens of thousands of miles. But if the temperature of the fluid rises above 220 degrees F the fluid starts to break down quickly. Above 300 degrees, fluid life is measured in hundreds, not thousands of miles. And above 400 degrees, the fluid can self-destruct in 20 to 30 minutes!"

 

[RVTRKN]

Yes, it was ATF, and Trans was torn down for inspection only purposes when discovered. I like the fact that my Trans will rarely go over 200* now with the cooling system. The Mobil Trans synthetic 50 that I run now has really quieted it down, but I still have noise, and when it fails an NV5600 will go in its place.

 

[AH64ID]

I am trucksitting for a friend who is overseas and drove his 2010 with a G56 a bit on Monday. I need to find out what fluid he has it in but it shifts very notchy compared to my NV5600 or my dad's G56. It also has a Valair Street DD in it and I am glad I have a SD in my NV5600 but his truck is quieter when lugging but it could also be the increased displacement of the 6.7 as they can run lower rpms a little better.

 

[Regcabguy]

I am trucksitting for a friend who is overseas and drove his 2010 with a G56 a bit on Monday. I need to find out what fluid he has it in but it shifts very notchy compared to my NV5600 or my dad's G56. It also has a Valair Street DD in it and I am glad I have a SD in my NV5600 but his truck is quieter when lugging but it could also be the increased displacement of the 6.7 as they can run lower rpms a little better.

They are notchy compared to the NV5600. The shift gates are very precise while the 5600 shifting seems sloppy. Seems like a lot of play in the shifting. The shop's NV5600 that I drove does require less effort than mine and it's running Mopar supplied fluid. I like the proximity of reverse and 2nd on the G-56 but in reality wish we had the iron cased NV5600 sometimes.
I've driven one of the original SBC 3250 DD G-56's and it is slower shifting than mine.

 

[AH64ID]

They are notchy compared to the NV5600. The shift gates are very precise while the 5600 shifting seems sloppy. Seems like a lot of play in the shifting. The shop's NV5600 that I drove does require less effort than mine and it's running Mopar supplied fluid. I like the proximity of reverse and 2nd on the G-56 but in reality wish we had the iron cased NV5600 sometimes.

I am not sure I would call it precise over the NV5600, more of a hesitation feeling. It still doesn't feel the same as my dads 06, which I just drove last month for about a week. I need to ask him what fluid is in it.

 

[RVTRKN]

Sounds like the syncro's are going.