I have an 89 F 350 that I tow a lot with. Usually 7-10K + 6800 for the truck. Sometimes I'm pulling 20K + the truck. My ZF is about dead and has the wrong ratio gears in it. I am faced with a reman ZF5 with the wide ratio or moving to a NV4500 or 5600. From what I have read the NV 5600 is a stronger trans.
Has anybody put an NV 5600 trans behind their IDI?? Did it work as desired?? Would you do it again??

Yes my truck is 4WD. Will my Borg Warner Tcase work with the NV5600??

 

If i was going to swap, i would be looking at the cast iron 6spd in the 00-02 dodges. There is the ZF6 too from Superduty 7.3s But the NV might be easier. I am thinking mine is toast too, gets hot fast and is developing a whine.

 

I put an aux trans to spilt the gears it work fairly well.

 

That doesnt really fix the transmission being shot?

 

that kind of weight is best suited for the f-super duty with the 4.63/5.13 gear options not the 250/350's.those are rated to a max of 18k and to get that,you need the 4.10 and E40D too boot not the zf5/3.55 or 4.10 combo.
might be time to step up to what you need.if you will be sticking to the pickups and overloading them,then you should consider building the truck up from where ford left off.my suggestion (is moving up to the f450 firstly) would be:
zf5 to (hd updated) E40D
3.55/4.10 pickup gears to 4.56-4.88 range
vac to hydroboost brakes

that combo would handle 20k gross no issue.however by the time you invest in the upgrades,it could and would likely just be cheaper to buy the f-sd rated for the 23-26k gross right out of the hole and be good to go all legal.

it's far better to have a lot more truck,than a little to less truck to handle the task.

 

no, but replacing the zf then putting in the aux would be easier than fab work for a completely different trans. the best part of the aux trans is you can get 3.55 mpg with 4.10s empty in double over drive.

 

The problem with your plan is it requires a CDL once you tie a trailer onto it, you get poor mpg empty, and you are required to have a dot number on any thing rated over 10,000. a stock 250/350 with a manual and 4.10s will handle that kind of weight.

 

Hauling a trailer up hill, having a ZF-5, 4.10s and a GVOD is amazing -- the 2nd-over and 3rd-over are the real lifesavers there, and 5th-over lets you cruise empty at 70 smoothly and quietly, with good MPG.

 

OK, I have a CDL and a a few of bigger trucks (Mack RD 690 & Western Star 4964). I am a one man business and what usually happens is I get the dump truck and loader to the site. Then I need the p/u and backhoe at the site. Rather than make numerous trips with the dump truck I would rather move the back hoe with the P/U. Going to a 450/550 would be fine except 60% of the time I drive the p/u as a ""grocery getter", 20% at 15K gross and 20% at 26K gross. Fuel in the 450/550 while running errands would destroy any profit margin. The F350 has 3.55 gears and the F250 has 4.10 gears. The 350 runs better and pulls better except when starting out at 26K. Rather than slip the clutch I start in the LO range. Once I get into 5th in the Low range I put the trans in N, the tcase in N, the trans in 2nd, then the tcase into 2WD Hi. I then go thru the gears again in the Hi range. I know the ZF's are not made for longevity, I am not sure about an NV5600? I would rather not go thru a transmission redesign/ swap, but I need a durable trans.
The GVOD - what is that?? Is it an overdrive "brownie" like US Gear makes?? I have heard that they have a tendency to gernade when pulling heavy loads. My info is 12-15 yrs old, are they any better now?? I would be happy with a fresh reman ZF and a durable brownie.
I think the EOD4 is an automatic - there will be NO automatics in my driveway!!

 

yes that's what they are talking about and no.they're no better.you can only use them when in 2wd and empty.no 4wd use and no towing.not what your after.
perhaps think about a small car for the "grocery getter" and the f-450 for your work duty.if your pickups are in decent shape they could fund the new vehicles that might fit ya better? nothing saves on fuel like running a 4cyl car when just hauling yourself is needed.i always say it's easy for me to say this,as id rather be driving a beater car than a good truck lmao.i just prefer cars.always have.

 

My aux is an old Watson that I pulled out of a 2 ton 60s Chevy, the under drive is great for starting out and backing up trailers, then for splitting gears I just use direct and over drive.
it's mounted be hind the trans so If the hubs are in you have to have it in direct, but you can put it in neutral to turn in sloppy stuff.
the gvod is a gear venders over drive that mounts on the back of the t-case, there used a lot in the racing world so they should be fairly tough, but I have no personal expedience with them. the 2300 new price price tag has kept me away from them

 

If your really worried about overloading your trans. I would suggest a 5 speed from an international setup.

 

I've been tinkering with the idea myself to swap the zf-5 in my project for a wide ratio 4 speed like a np-435 and putting in an aux box, like the ranger torque splitter, between the bellhousing and the transmission. That way you have a "4 speed" (2-3-4-O) for getting grocery's and a "many more speed" for hauling. It will probably be easier to put an aux-box behind the transmission like Red454 though. Just a thought.