NIsaacs

Thanks, it has 3.55's and yes I tow in 6th all the time if I am at 60 mph and above. The trip I just made was a slow road, no freeway but lots of steep grades including Salt River Canyon. When I tow my sled puller in the Rocky Mountain states I average 12 mpg, I am at 19k gcw. Local round trip hauls with my dump, I average 13-13.5, loaded 26k+, empty 14k.

Just make sure they are "new" Bosch injectors. You will need a boost fooler and elbow for best results. I just made a round trip, 389 mile run with my '01 hauling a loader bucket both ways, probably about 8200 lbs total weight of the truck and got 19.16 mpg on winter fuel. This is with 285/75x16 tires and 300k miles on my RV injectors, set on level 5 with the Edge Juice.

Another plus of changing oil is you can inspect what is in it, possible brass or anything at all that don't belong. When I tried it in my '01, cold days were the worst, warm days were fine. Shifting quality was/is night and day between the 50w and 15/40 engine oil, in my NV5600. It was like the 50w synthetic was just too slick.

According to this invoice your tranny pretty much received a complete rebuild, including syncro's. Maybe the heavy twin disk clutch is giving you false feelings of syncro issues, slow your shifts down. Again, I would try a different gear oil before I pulled out a (possibly) perfectly good tranny. https://mopar1973man.com/topic/16584-nv4500-broke/?do=findComment&comment=216697

Why would a builder not inspect and repair as needed, especially something as wear prone as syncro's? I would not be happy about this. I think I would change out the 50w gear oil and try something else first. My '91 Dodge w/Getrag and '74 Ford w/Clark 280VO likes it. My '01 Dodge w/NV5600 did not.

Flat bed dually's take power and fuel just to roll. My Ford only gets 16 mpg and it is a VE pumped 12 valve, way less power than yours. The flat bed is 8' wide, air horns, full size west coast mirrors, two transmissions and stacks all take a toll.

My NV5600 takes one gallon. I never overfill. I change every 36k miles with 15/40 engine oil. I tried 50w synthetic manual transmission oil one time, it didn't like it until it warmed up a little. Maybe it is too slippery too, IDK. I assume the Redline you used is a synthetic, what weight? I would say your shop did the change just fine. There are overfill stories all over the internet, however, any manual transmission manufacture will tell you to "not overfill". I drain out of the bottom PTO cover bolt and fill till the oil runs out of the fill plug. Every other change I will pull the cover and clean the magnet and sop up the small amount that is in the bottom.

I had the same problem with only changing two tires at a time. For some reason old Michelins don't play well with a set of new tires. Here is a thread on my experience. I recommend changing the front's out too. https://www.turbodieselregister.com/threads/strange-michelin-behavior.258287/

I think Mike has 4 wheel abs, the tone ring failed in his front unit bearing. I think you said your truck was 2 wheel ABS, same as mine. So no, on the diff bearings.

Mine started out doing what yours does. It first started out acting up when I was towing heavy on a hot day and climbing long grades. It was related to hot under hood temps. After I topped out and cruised on the level it would work fine again, until the next hill. At first I thought it was the rear axle sensor, that climbing, it raised the temp and then cooled off on the level. So I changed it, no help at all. I don't remember how I determined it was the module, I think I guessed Anyway, I bought a used one off E-Bay and it fixed the issue, that was several years ago. It is vehicle and 2 or 4 wheel abs specific. It did act up one time this year. I was towing heavy out of Phoenix this past summer @ 115*. The long grade out of Superior, 5 miles of 7%, water temp at 219, it quit for a bit, but just this one time.

It might be your ABS Module. https://www.moparpartsgiant.com/parts/mopar-module-anti-lock-brakes~5015528ad.html

Some good info here on my thread at TDR, (Ford twin disk) It may or may not apply in your case. Take a good look at the pictures, they tell the story. https://www.turbodieselregister.com/posts/2560735/

That's what I used for years in my Ford dually when it was a gasser. The Cummins is gear drive, Holset 8.5 cfm air cooled. When I need portable air I have one of these. https://www.northerntool.com/shop/tools/product_200660640_200660640

You did good, I only got 220k on my radiator. It was my bad, I only changed coolant once in that time. I replaced it with a Spectra also. I have since changed the coolant twice in 110k miles. What is your take on the difference in cooling capacity going from two large cores to 3 smaller cores with the same total core thickness? The early 2nd gens were 3 core and when they changed out the radiator for a 2 core the performance went down. My oem was a two core, the Spectra I installed was a two core. I am looking at a three core but hate to not improve from my two core. Also, for some reason when I try to post, an ad gets in the way. Why is that? I have to jump threads to get rid of it because it covers my post button.

Did you go with the upgrade input shaft? I would also take a good look at the supplied clutch release bearing, some are not up to the task of a long wearing twin disk. Southbend finally upgraded to Aetna bearings. SKF is also good stuff. https://www.aetnabearing.com/products/aetna-clutch/clutch-release-bearing-assembly/

How did you manage that? Are you going to share? A good single is about $600 w/flywheel and a twin is about a grand.

Just slide it into two gears, 2nd and 4th and that locks the output shaft.

1500 hp. sounds like a good number.

No, overdrive (6th) is inside the case, better support and it is a bigger tougher tranny all around. The issue with the NV4500 is 5th gear is outside the main case. So any slight bearing slack on the counter shaft or main shaft, one or both 5th gears can tip slightly, the mismatch causes tooth breakage. The 5th gear nut issue is caused by the angle cut gears always forcing the 5th gear against the nut, under torque. The bottom, matching counter shaft gear is only held on by a snap ring, but the angle cut gear is forced toward the case so it don't fall off like the top gear can. The NV4500 weighs 200#, the NV5600 is 360#.

GAmes (TDR) went through 12 of 'em. Running a G-56 now. https://www.turbodieselregister.com/threads/why-does-my-nv4500-always-die.266177/#post-2580990 Link on his install: https://www.turbodieselregister.com/threads/221115-Mission-G56-(pictures)?highlight=mission G56

Per Quad 4x4, TDR issue 44 page 142, one of the most frequent transmission failures, is due to misalignment of the input shaft drive gear with the countershaft driven gear, when the pilot bearing fails. I assume because of the angle cut gears, it only takes a slight amount of misalignment to cause havoc. They also point out, that if the thrust bearing is loose on the input shaft, that the in and out movement will damage a pilot bearing or input shaft nose. So yes, both possibilities exist. Good Call Mike and KATOOM with your in depth thinking. I will be watching and learning on this thread. They also claim, the oem bearing kit is the only way to go. That aftermarket kits are not up to the task. See Tech Note 2: in this link. https://torqueking.com/product/10005/qu10005-1997-2005-complete-nv4500-bearing-and-seal-kit-for-dodge/ KATOOM, since you as such a thinker, do you care to comment on your lube comments?

I wouldn't, that should be some fine oil. I think Mike's report on the pilot bearing is spot on.

The FSM says 280#, I go to 450#. I use the 3/4 drive nut wrench with my 150# and a 3' pipe. https://torqueking.com/product/882036/qt2036-3-4-drive-mainshaft-nut-wrench-quadtool/

I would guess the pilot bearing pocket in the flywheel was machined too large or the Chinese bearing was slightly small. I would also guess that since 5th and reverse both have problems that there is a major issue with the counter shaft bearings. I dread the day my 6 spd wears out.

If you upgrade the disk hub, Mobil 50 or not, you will get noise. My tranny was quiet too, with my stock clutch. Your clutch looks like a plain jane 13125 (13" x 1.250" spline) stock type Luk. Better than the 12.3" it was born with, but not much. With your power level I would move up some. I would guess that clutch to be rated about 400/800. You need one in the 450/900 range+