rebal

I'm done this has got to be the worst transmission ever made .I got 150k out of the original pulling backhoes and other heavy loads .after having a syncro repaired at 150k I cannot get 1000 miles out of it .I have had standard transmission and gear rebuild the last 3 (1 and 2 local) and now it's blown again. it seems to let go just coasting or at really light power .second rebuild went 200 miles .my trailer weight is gvw16900 but the last 2 time I checked the scales I was only at 11800 so I don't think it's over loaded. I now have 155400 and it broke 4th again. are the new parts this bad? any ways I'm done just bought a new g56 to swap in .my buddy has a g56 in his 08 and pulls bigger loads with no issues yet so I'm hoping this will work out.picture and details of the swap with installing a oil pump and cooler to follow

johnh

iv'e had mine since new and i think it's a good trans. you must be doing something that nobody else is doing, maybe you are using the wrong lube, or not enough............by the way, i no longer have the 12,000 lb fiver that i used to pull

rebal

used mopar first 2x then amsoil then torqo it's not the lube all 2qts over full.honestly I think the case is bad the first time it grenaded I was fully loaded and it locked up rearend and slipped the clutch. every part from clutch pilot to rear has been replaced.I don't hot rod the truck and after logging over 2 million miles OTR I would think I know how to drive a stick (no I don't float the gears) in this truck .the one thing I did notice is that when I bought the truck Trans temp stayed around 160-190* now it seems to run 220+ just going down the road, and I never tow in OD. we have an 05 with same Trans no issues at all so I am at a loss

SIXSLUG

I'm thinking something is wrong on the rebuilds, Odd nobody else is having them go like this. Mine is fidgety and shifts way smoother when towing heavy I've noticed, doesn't like to shift smoothly when cold and gets pretty hot when at operating temps....

gorms

Any idea on what is breaking? 5600 is a pretty stout transmission, good luck to you with a g56 but I'm not sure it's much of an upgrade. A properly built NV will stay together under some serious stress.

I'm sure you have contacted standard? 220 is very hot for an empty truck, something isn't right and is getting overlooked.

deere country

The higher than usually temp is the give away to something going on internally. Not surprised that another nv5600 has turned up problematic. Some think the thing is the best thing on earth but I would disagree. I have towed home nearly as many nv5600 trucks as autos and their are a bunch more auto trucks out on the road vs 6 speeds.

If you want to stay with a 6 speed manual look into the ford ZF trans. They don't shift as smooth as a nv but if that's needed get an auto. The zf runs an internal oil pump and 3 times the oil in them. Ford used it in their medium duty trucks with a much higher gvw than a 1 ton truck. It's not cheep to swap but doing an nv 6 times isn't cheap either.

saggonwaggon91

Like stated above, there is a problem with the rebuilds. I would look into getting a complete NV5600 replacement before going with the G56...

rebal

last time I talked with Richard at standard transmission in AZ and told him to please see what's going on seem 4th is the problem . the time before it pulled 3 teeth out of 4th and then broke other parts from the teeth going through. this time I heard that sickening sound as it got my adrenaline flowing ,of glass cracking ,and I emedetly shifted to third and looked at my wife (lost 4th) and she's like "how? we're going down hill coasting! "anyways drove to our destination and back home using 3 and 5 but I was 250* running flat ground by the time I got home.when I got home pulled the trans (I'm really good at it now) and through the stick hole could see 4th gear was ok but the gear it rides on on the main shaft has 3 teeth gone right down to the base.I am so at a loss and sick too over this.btw I called standard transmission in AZ no longer there so I Googled it and said permanently closed.

KATOOM

Sounds like you've had some poor rebuild workmanship, bad parts, cheap Hecho en China parts, or lubrication problems. Or.....a combination of all said. Not only is the 5600 a stout transmission but you're not doing anything out of line which would constitute abuse. Well.....unless you simply dont know how to drive a manual and are the true reason for the problems.

But that said, I'm giving you the benefit of the doubt here because the fluid temperatures tell a different story. Your transmission should rarely see over 200* unless you're towing in the mountains in summer weather. Even at that 225* would be HOT. Any unloaded truck with a manual transmission would see temperatures no higher than 150*. If towing heavy is a regular thing then Fastcoolers are a good investment.

You could switch to a G56 or find a competent transmission builder. I've heard good things about Standard Transmission but maybe you should try Blumenthal Blumethal or Quad 4x4 Torque King 4x4 - Your 4x4 Experts!

rebal

well like I said I have 2 million miles OTR with 5 and 4 9,10,13,18 speeds and the original NV5600 got 150k before the first catastrophe .and I hauled backhoes and other heavy stuff including a 38k excavator. lol. but now 5 in 5 thousand miles. and it has fast coolers and a heat shield on exhaust next to Trans. on a side note the 05 with nv5600 was overhauled by the same place as this 01 at 325k and it's been 3 years now. I think the case is off kilter some how . and now it's sorta a mute cause .I just got a reman G56 and a crank spacer so I can keep my SBC, drive lines getting cut and stretched and re balanced should have it back together in a couple days...... crossing fingers! and if this blows im trading it in for a 3 wheel bike with a basket and bell

KATOOM

Whoa.....! You drag around a 38k load behind your truck? Well I have to say that it sounds like if this is anywhere near the norm for your adventures then I dont think any transmission you stick in there will stand the test of time. Matter of fact.....kudos to the 5600 that lasted 150k miles.

And I agree, possibly your transmission is just tweaked.

Just noting too that the G56 is known for splitting when subject to huge loads and/or huge power.

It seems you better start combing through Craigslist for that trike. Might have to get the bell and basket from Walmart though.....

rebal

38k was just a 1 time move it was a little much😫but most of the time it's just pulling 33' toy hauler camper anymore. got bigger trucks for the the big stuff. and it's always let go pulling camper on flat ground or starting down a hill never on a up hill or under a load . wife said she found bike already just waiting now😂and for what it's worth Truck dynoed at 334 /779 and that was when mach injectors and catcher first hit the diesel market .been running that setup since 2003 it's just the last 3 years it's blowing 4th. or more.

rebal

well it's in .was a fairly easy swap for the nv5600 to g56 only things needed was crankshaft spacer with longer bolts removed starter spacer, modify rear transmission mount lower 1"and shorten drive lines 2.75" and wired reverse lights. the g56 has a fatter bell housing so a slight rearward tilt of the engine was needed to mate the two but once together it gos up with lots of clearance.I also added a oil pump and cooler and filter setup to the Transmission. figured it was an easy thing to do and I can just spin on a filter every 30k and add a quart of delvac 50.should keep floating particles out of my oil too. so far other then reverse location not a big difference in the way it drives.
I will post back as miles roll by .next trip will be San Diego in a month but I'll have the wife drive it to work for a few weeks to make sure alls good and then go over everything once more. keeping fingers crossed.

SIXSLUG

I hope its a good match for you.

I'm still mulling over why your 5600 kept failing. I know mine had regular gear oil in it and that's what killed it, they couldn't even get the mainshaft apart with an 80 ton press!!!

I wonder if it could have been non spec'd assembly lube or something that just cooked when run.....

KATOOM

80 ton????? That much pressure should have crushed it if it didn't come apart.