Who knows NV4500's really well? (2 Viewers)

[GLTHFJ60]

I do know the 6bt is a lot more motor than any of the stock OEM diesels and I'm hoping a 4bt isn't as hard on parts.

How hard the 4BT is on parts depends on two things:

1. Power output of the motor ( how built it is )
2. Your personal driving style

However, I think the big problem you're going to see with the H55 is that it doesn't have enough overdrive. The 4BT is most efficient, and makes peak torque, around 1800 RPM, so that's where you want to be at highway cruising speed ( if you drive on the highway ). For crawling, the NV4500HD is the obvious choice, with more aftermarket GRB support and a lower first gear ratio.

I'm really happy with my NV4500HD and Dana 300 combo. Even though the D300 is center output, I'm running it with a FZJ80 rear axle, and have been for 4 months now, with 0 issues and 0 vibes. The only adapter I have to use is to mount the D300 to the stock Dodge 4WD output housing of the NV4500HD, but it's just a clocking ring, not a whole assembly with bearings that can fail.

You can see the adapter below. It's the shiny aluminum bit between the D300 case and the NV4500HD output housing.

 

[boots4]

... wouldn't mind test driving any cruiser with a diesel swap!

The next time we're in the same area you are welcome to drive mine. Recent tunes and maintenance is making it even more enjoyable for me to drive it.

. The 4BT is most efficient, and makes peak torque, around 1800 RPM, so that's where you want to be at highway cruising speed ( if you drive on the highway ).

Slight hi-jack but I think there are a couple factors involved in the right cruising RPM. Some that come to mind are tuning, tires, gear set up (diff), intended use and driving style; those combos start to play around with that cruising RPM number with tuning having the potential to playing around with the peak torque RPM. I think a good cruising range to aim for the 4bt is 1800-2000 rpm. But I definitely agree that if one can keep their foot out of it, the more efficient it can be.

 

[GLTHFJ60]

Slight hi-jack but I think there are a couple factors involved in the right cruising RPM. Some that come to mind are tuning, tires, gear set up (diff), intended use and driving style; those combos start to play around with that cruising RPM number with tuning having the potential to playing around with the peak torque RPM. I think a good cruising range to aim for the 4bt is 1800-2000 rpm. But I definitely agree that if one can keep their foot out of it, the more efficient it can be.

I completely agree. I'm still working on finding my optimal cruising RPM.

One of the reasons I love Cummins so much is because they give us SO MUCH INFO about their motors. I have a CPL 858, so this graph isn't 100% accurate, but it gives us a pretty good starting point.

 

[Kief]

boots- I would love to test drive your rig... How about coming down to McGrew!

 

[cody c]

How hard did you wheel it before having issues?

not that hard, remember too Im open diffs, I dont get out as often as Id like, and half the wheeling I do is in snow. I havent been slamming it hard in mud holes or in low gear on the rocks, though I do have a heavy right foot on pavement in third or fourth gear sometimes. The narrow RPM band of the motor coupled with short first and second and the torque of the motor makes it unsuitable to drive it hard in first or second (high gear). It makes enough power to idle along rough trails down to about walking speed in second gear without stalling on most terrain

I replaced a trans mount, I think that with the trans mount gone it may have affected harmonics to every other part, allowing it to shake things loose a bit easier. If you do have one and use a split case, try using a toyota split case gasket between the two halves and thoroughly clean the bolts holes and thread lock them before you reasemble, then leave it for a day or two for gasket goop and thread lock to cure before filling with oil - if you are putting one together or reasembling.

I didnt have any issues with it for about 4 or 5 months.

 

[Jason Andrews]

Well, its neat to see this old thread, and to update it, I have less then wonderful news.

After a few years with the NV4500/AA adpapter/Split case I can tell you this: I wouldnt use the AA adapter, I would rather a different transfercase based simply on the fact that Ive had issues with the adapter.

Its broken the $90 sealed bearing in it once, leaked fluid out of a hole I couldnt see from the front of the t-case, and now pushes all the fluid into the t-case till it runs low. As it is now I have to top up the transmission every 4-6 months, and the intervals seem to be getting shorter.

With the NV4500 from behind the cummins, they used a specific carbon fiber synchro disc which is particular about what kind of oil its in, for this trans it needs a $35CAD a bottle of oil, the case takes about 4 or 5 bottles from empty, this gets expensive after 3 or 4 fill ups. I believe the non cummins versions did not have the carbon fiber synchros though, so they dodnt need "magic synthetic oil" from what I understand.

I dont have any issues with the cruiser t-case, I have killed a clutch, a couple diffs and maybe some other parts, the split case held togther, but it did seem to have the two halves work a bit loose and leak pricey transmission oil, though Im not sure if its cause I used black gasket goop instead of a gasket, I did use thread lock but maybe some of the threads were still oily.

Ive heard some things about a land rover t-case. If I did it again I would either find a NV4500 with a transfercase on it, or take a better look at the rover t-case.

As you can probably tell, I am less then happy with what I got from AA, though I am glad they have options for the aftermarket crowd, perhaps they need to look at their R&D a bit better.

Just my experience, your mileage may vary.

Hmmmm, I am having a similar issue. I'm leaking tranny fluid from somewhere I can't see and it is dripping from my tcase. At first I thought it was the pinion type seal on the adapter that keeps the fluid in my tranny and out of the adapter. Tranny shop said it wasn't leaking and couldn't find leak anywhere. I have been looking for a hairline crack on something.

I am swapping turbos and haven't driven it in 3+weeks. The leak on my driveway has gone from a quarter size to a basketball size without even driving it.

 

[cody c]

Hmmmm, I am having a similar issue. I'm leaking tranny fluid from somewhere I can't see and it is dripping from my tcase.

I am swapping turbos and haven't driven it in 3+weeks. The leak on my driveway has gone from a quarter size to a basketball size without even driving it.

There was a bolt hole on the flange to the split case which did not get a bolt through it on mine, this would leak onto the adapter.

There was no hole through the split case so I couldn't see it to put a bolt in it or figure it out when I bolted the split case to it. The bolt hole in question is on the driverside, near where the output shaft of the adapter passes into the split case, because its a threaded bolt hole I dismissed it thinking it wouldn't be the problem, but when I pulled it apart the second or third time I noticed there wasnt a bolt to go through it.

The double sealed bearing included with the adapter cracked in two pieces where the split ring pops into it, and allowed the bearing to pass more fluid from the trans to the adapter and t-case, and then the adapter leaked and the t-case filled with oil. I dont know why or how the bearing broke, but it did break at its weakest point, I accidentally noticed this when replacing a clutch that had broken all the disc springs and the disc had separated the friction material from the metal structure and splined center piece.

Despite being a sealed trans, check your fluid level on your NV4500, it may have moved oil to the t-case, as it is I think I may have to add fluid to mine this weekend when I get time. My split case also weeps along the surface between the two halves and a bit from the bolts holding the two halves together, this may have something to do with the trans pushing fluid into the t-case as well.

Ive given up on the expensive fluid last time, just putting in synthetic gear oil. I'll let you all know if I have any issues with the synchros.

 

[Kief]

If there is that much desintigration of parts and pieces I would start to wonder if everything is centered, true, perpendicular and in alignment. It is possible an adapter, bellhousing, tailshaft or a flywheel isn't within specifications.
I noticed the bearing in the 5spd to splitcase kit from AA looked a little generic.
I also rember putting in a allen head plug with sealant in one hole- is that the same one you mentioned?

 

[cody c]

If there is that much desintigration of parts and pieces I would start to wonder if everything is centered, true, perpendicular and in alignment. It is possible an adapter, bellhousing, tailshaft or a flywheel isn't within specifications.
I noticed the bearing in the 5spd to splitcase kit from AA looked a little generic.
I also remember putting in a allen head plug with sealant in one hole- is that the same one you mentioned?

The bearing with the AA kit is generic, it can be found at transmission shops and is a SKF or similar double sealed bearing.

Not sure about parts being out of spec, I had issues breaking the old flex plate with the previous setup, then I went to the flywheel and dodge bell housing etc. The previous setup was the trimmings off a toyota and dodge bellhousing brazed together by the PO. After I had the truck offroad enough times I broke the flexplate around the bolts at the crank. The shop that did the work drilled and tapped 6 holes inside of the dodge 8 holes on the crank, then machined a pilot bushing to center the flexplate.

None of the bolt holes were oblonged and all were machined, the machining for the bearing to sit in wasn't damaged or oblonged. The clutch is brand new last fall BTW.

You are correct about the Allen head fill plug, I checked fluid on mine on the weekend and it was fine, though I thought it might be a bit low.