using 5th gear.

[71 LONG BED]

Hey MaxKlinger, here is all the info you'd wanna know on the Ranger Gear Splitter. http://www.fordification.com/torque-splitter.htm

[Galaxie64]

Even though 1900rpm at 65 isn't too bad with a 4 speed I'd personally rather have a 5 speed. I've towed many many loads with aATs turbo'd IDI 7.3 with a ZF5 behind it and 4.10 gears and you just have to be smart about when you can go into OD. The diesels will start to warm up real good if you lug them too bad in OD and then you learn pretty quick what you can and can't do in what gears. I am not a cummins expert but it has always been my understanding that they do not rev very high so a 5 speed might be better off behind it.

[averagef250]

The small block s5-42 ZF 5 works great behind the 4BT. The diesel one would be better since it's close ratio, but you'll need a custom adapter for it.

[briney]

where i am at the moment is i would like to gear the car fro 2100-odd in direct at 65. this by my calculations means 3:1 diff gears with my 31's. i would like to stick with 31's, as they are easiest to get in out of the way places. i don't plan on towing often with it,but when i do i wouldn't mind still having ok mileage. what sort of overdrive ratio is in the ZF ? also, the gearset out of the diesel one can be put into the gasser case can't it ?

[briney]

also, what is the 3-4 gaplike on the zf 5 speed. a big gap here seems to be a common failing. people talk about using a 3200 rpm governor spring to get around this.

[HRDROKN]

The ZF 5 speed is a great tranny. The Ford T-19 4 speed was made in close ratio version in the mid 80's.

Towing in 5th with a cummins NV4500 is not a good idea. NV4500's are not stout enough for the 5.9 and 5th gear fails in every one of them eventually towing or not. The 5.9 will tow anything in overdrive with the right gears and minor mods. Just because the engine will do it doesn't mean the tranny will take it.

NV4500 5th gear problem is a gear retention design failure and not a direct problem with the ability of the gear to hold the power. This design problem is correctable.

Also not to steal this thread are be argumentative.... all my readings to this point have indicated that the NV is the better of the two trannies, but I would also have to say that I hadn't been on many Ford sites until this project started I will have to see if I can dig up some old writings

[averagef250]

I am a bit biased against the NV4500 because I see them broken all the time. I rebuild 2-3 of them/week from behind cummins engines. My take on the whole "NV4500 is a great transmission" deal is that cummins dodge owners get a bit of a complex believing thier trucks are so great. The NV4500 will take a good bit of abuse and a lot of power through it, but every single one of them will have a 5th gear failure at some point. Most go south around 140-160K miles, in reality the tranny's been bad since around 100K, but by 150K or so 5th gear is starting to get sloppy enough and the rear mainshaft bearing has been spinning on the mainshaft to the point where it's getting real sloppy, reverse thrust has about a 1/16" groove worn into it and all it takes is a good load in 5th up a grade to spit the 5th gear splines off the mainshaft.

Yes, you can fix the 5th gear issue with the NV4500. Quad4x4 makes the torque king mainshaft and 5th gear that works excellent. The problem is you can go with a much better tranny than the NV4500 by the time you spend the dough on a torque king shaft.

In addition, NV4500 ratios aren't that great. Ford diesel trannies are close ratio. I'd much rather have a close ratio ZF5 over an NV4500 behind a low revving cummins. The NV4500 is rated for 450 lb/ft and the ZF5 S5-42 is rated for 420. The newer ZF5 is rated for 470 lb/ft. The ZF5 and NV4500 guts are the same size. The ZF S6-650 makes the NV4500 look like a joke and it's rated for 650 lb/ft and it has a built in pump and provisions for an oil cooler and holds way more fluid.

[HRDROKN]

I'm listening...

I have not yet seen a post of a NV4500 with the 5th gear nut fixed running proper lubricant level (which is more than factory recommended) have any further failures behind bombed cummins motors...

I have a ZF6 in my truck and its ok and works fine, but as i was told several times in the first stages of configuring my converson is the ZF6 is not built to handle that kind of torque from a high hp cummins, and the ZF5 is worse, and personally i dont like how the ZFs shift, once you learn it theyre ok but they are extrememly touchy, and like you said you have to buy the tranny and a clutch and an adapter plate which is very pricey and im having second thoughts on mine, i had to grind the hell out of my tranny bellhousing to make the starter fit, and the bolt holes for the starter are in aluminum (that lasted real well) and i worry about the mix matched clutch components, personally in your situation i would go with a NV45/5600 they are very nice trannies good to shift and they are already setup and designed to work behind a cummins, bellhousings clutches starter etc, and the 5600 is no longer made and im not sure what 6speed replaced it but its just as nice. Yes you have to deal with tranny mounts and a different transfer case and shifters, if i had mine to do over thats probably what i would have done, my 02 cents worth

[averagef250]

5th gear nut has zero impact on the NV4500's troubles.

There is no "5th gear nut fix". The nut is the problem idea is dodges doing. Around '97/98 dodge realized they were having tons of the NV4500's failing early so they came out with a nut fix which was replacing the original nut with one of a different design. Really, all they were doing with replacing the nut was tightening the holy bejebus out of the new nut in hopes the trannies would last longer. Starting in '99 all NV4500HD's from New Venture came with Dodges "new" nut. I know a guy who bought 160 new surplus cummins NV4500's from new venture with the "old nut" design from NV. The nut design makes no difference in how long 5th gear lasts.

The mainshaft itself and the splines in 5th gear are the issue. The Quad4x4 shaft does work. The Quad design locks 5th gear onto 2" of interference fit splines with tapered fit primary nut, loctite cylindrical bonding compound and two additional jamb nuts torqued to 325 ft/lbs.

[HRDROKN]

Yes, I knew that the mating of the splines was a design problem, but I'm not sold as to what type of failure that in of itself was causing. The problem that I'm aware with the 5th gear burning up is related to the retaining nut backing off, letting the gear walk on the splines and reducing the gear/gear contact area... thus creating even greater stress and heat, until failure....

[averagef250]

No, there is no such thing as the nut backing off.

Would you believe there wasn't a nut-coming-loose problem if you torqued the nut to 325 ft/lbs and tack welded it to the mainshaft, then 2 years later at 80K miles (in a hotshot truck) 5th gear is stripped again and when you pull it down the nut is still welded exactly where you put it?

If you saw the dozen or so various design NV4500 5th nuts you'd see that regardless which design you used each and every one of them would be very impossible to get to back off without first removing the locking screws and/or chisel off the peened over locking flange.

The issue is the frequency of the cummins vibrations going through 5th gear causing fretting between the gear and the shaft. Fretting is why NV4500 gear oil looks red/brown when it comes out because it's full of iron particles from 5th gear splines.

The gear itself being loose really isn't a big issue. Personally, if it was just an issue of the gear loosening I could care less. The issue is when the gear comes loose it's what clamps the rear mainshaft bearing to the mainshaft. When the bearing is no longer clamped it starts to spin on the shaft. After 20-30K miles the bearing spinning has worn enough into reverse thrust and depending on how hard you run the truck in reverse, reverse gear itself can then start slamming into reverse thrust from the other side compounding the problem. The more the bearing wears and reverse thrust wears away the more internal clearance the tranny gets, the more the mainshaft deflects from the countershaft under load. when the mainshaft deflects from the countershaft it sideloads the input, putting extra stress on the already undersized cummins pilot bearing and increasing the chance of stripping the input/countershaft forward gear.

[HRDROKN]

Out of curiosity I did a search this evening on 5th gear failures in the NV4500 over on the TDR website and my approximation is that 90% + of the failures the symptom was that the 5th gear nut had backed off.

NOTE: An improved output shaft, gear, and nut is available from Standard Transmission. This revised shaft is fully splined to reduce the 5th gear vibration that pounds the nut loose. All of the special tools are available from SPX Miller but if your gear is loose the only one you will probably need is the nut wrench - special tool 6743. The other tools can be improvised.

I also noticed that those that repaired 5th gear after a failure and used the same splined shaft had repeat failures by approximately 15-20% So it would seem that to get a correct repair a new shaft is required. Of those that did the 5th gear nut repair before any trans problem, have reported multiple 100K's without failure. Some of those tow 23K on a regular basis.

[averagef250]

I'm not bothering to write anymore on this. 99% of the TDR guys are just like the know-it-all dodge owners who come into my shop after thier tranny's have bit the dust.

The NV4500's the toughest thing in the world until it comes apart on them.

Here in the real world, the NV4500 is not some gold plated super tough super tranny. It's an undersized problematic time bomb behind a cummins. The internet is a wonderful place full of biased opinions.

The NV4500 is the perfect tranny to go behind a big block. It is not up to the cummins.

You can immediately discredit anyone who says the nut backs off. If you've actually worked with NV4500's you'd know full well the nut does not turn on the mainshaft.

I know ONE guy who has a 96 Cummins 4x4 with 350K on it and the original NV4500 untouched. It's worn out, sloppy, noisy and you can feel the slop in 5th on and off the throttle. I also know a guy who's done in 6 of them in 300K. He's a hotshotter, but he's not abusing the truck.

[HRDROKN]

I'm not bothering to write anymore on this. 99% of the TDR guys are just like the know-it-all dodge owners who come into my shop after thier tranny's have bit the dust.

Hey... more power too ya! To think that one opinion is the only right answer to the subject is typical. To think that the Ford community is also more righteous than the Dodge community is also typical.

Having seen many things in the lubricant industry.... I take it all with a grain of salt.

Personally it doesn't appear that the ZF does any better than th NV behind the Cummins.... just trading one set of problems for another!

[customcrewcab]

to tell somone that who has been there done that then tell him he's wrong dudes just trying to help you and others out. just becasue you don't want his info doesn't mean others don't.