Builds Dirty Koala Build - Cummins Common Rail + NV4500 + HF2AV Swap (6 Viewers)

[Dirty Koala]

But don’t you also have to machine down the splines on the output shaft of the transmission if you don’t use the intermediary shaft? Isn’t that also making it slightly weaker?

No you dont. The diameter of the NV4500 mainshaft and the HF2AV input is virtually identical. The machining is primarily to cut the splines into the shaft after you have cut off the uneeded extra length of the 2wd mainshaft.

 

[Will Van]

No you dont. The diameter of the NV4500 mainshaft and the HF2AV input is virtually identical. The machining is primarily to cut the splines into the shaft after you have cut off the uneeded extra length of the 2wd mainshaft.

Oh, ok gotcha. Does Diesel Adapters still make the adapter plate between the trans and t-case?

 

[Dirty Koala]

Not sure...probably. If you search around here you can find the cad files that can be given to any machine shop to create. They are now open source to the mud community.

 

[Will Van]

Not sure...probably. If you search around here you can find the cad files that can be given to any machine shop to create. They are now open source to the mud community.

Thank you, sir! Love your truck BTW!

 

[GLTHFJ60]

But don’t you also have to machine down the splines on the output shaft of the transmission if you don’t use the intermediary shaft? Isn’t that also making it slightly weaker?

Like Morgan said, that is not the case with the NV4500. Even if it were the case, the modified shaft would be as strong, or stronger, than the factory output shaft, aka the transfer case input.

 

[Will Van]

Like Morgan said, that is not the case with the NV4500. Even if it were the case, the modified shaft would be as strong, or stronger, than the factory output shaft, aka the transfer case input.

Apologies. My mistake. Thanks for the great intel. Searching for the trans to t-case adapter CAD files now.

Thanks again for all of the great info!!!

 

[Mr Cimarron]

Apologies. My mistake. Thanks for the great intel. Searching for the trans to t-case adapter CAD files now.

Thanks again for all of the great info!!!

I have a friend that will be attempting to machine the adapter for me. If it works and he wants to make more for some extra cash I will post up. I'm a month out from even thinking about as I want to bring him the NV4500 4wd tail housing and transfer case so we can make sure everything bolts up nicely. I believe the adapter in the file has some extra material on it that needs to be ground off so I want to modify the CAD if that is true. The 2WD main shaft will be sent off to the recommended shop (can't remember the name at the moment) that knows what to do already.

 

[Will Van]

I have a friend that will be attempting to machine the adapter for me. If it works and he wants to make more for some extra cash I will post up. I'm a month out from even thinking about as I want to bring him the NV4500 4wd tail housing and transfer case so we can make sure everything bolts up nicely. I believe the adapter in the file has some extra material on it that needs to be ground off so I want to modify the CAD if that is true. The 2WD main shaft will be sent off to the recommended shop (can't remember the name at the moment) that knows what to do already.

Very interested in the adapter, especially if you modify the CAD file to make it more refined.


Just to be clear, you guys are using the NV4500 4WD heavy duty Dodge transmission, but modifying the 2WD output shaft so that it mates to the Toyota transfer case? Is that correct?

 

[Mr Cimarron]

Very interested in the adapter, especially if you modify the CAD file to make it more refined.


Just to be clear, you guys are using the NV4500 4WD heavy duty Dodge transmission, but modifying the 2WD output shaft so that it mates to the Toyota transfer case? Is that correct?

Yup. Two ways to think about it. You can buy a Cummins 2WD trans and take it apart to modify shaft and then buy a 4wd tail housing. I just ordered one on eBay for $83 shipped. Or you get the HD 4wd model and rebuild using the 2WD shaft. I believe thats how it goes.

 

[cody c]

I believe there is some variations of the 2WD output shaft on the NV4500, maybe check if the part numbers are same/different for chev and dodge 2WD's, I believe when I searched on ebay they looked different.

Also looking forward to an AWD T-case back in my 80 for winter roads here.

 

[Dirty Koala]

I think all of us that have gone the NV4500 to HF2AV route had started with Dodge 4wd trans and modified a new 2wd mainshaft.

 

[Dirty Koala]

Havn't posted in a while, just been enjoying the rig. I was having a bit of a hard time starting...slow cranking which I figured was a toasted battery. I had Dustin and the boys at State Automotive in Midvale, UT replace both of the start batteries with Group 31 Duracell AGM's...total of 3 of those bad boys in the truck now. I also had the condensor replaced, and now have ice cold A/C! I cleaned up the terminals and cable lugs with baking soda/hot water and a tooth brush. Now the motor fires up almost instantly.

This past weekend I took the family for a quick camping trip up Diamond Fork just east of Spanish Fork, UT.

Next on the to-do list is wire up the Cummins grid heaters and wire up the harrop lockers including dash locker lights.

 

[Will Van]

In mine I moved the engine 1/2" forward to better clear the steering box timing cover interference with the DA positioning.

I kept the stock fan hub and fit a 89-90 non I fan it's smaller than the intercooled truck but still pulls a ton of air. No issues with clearance and the stock tach sensor this way as well. Sees to work so far and I have 1" clearance to the rad.

The mechanical fan would hit the bypass nipple on the top of the radiator.
View attachment 1263089

I cut the nipple down and screwed in a stainless machine screw with thread sealant. It's in there good and tight, with plenty of fan clearance.
View attachment 1263090

There is a good 1" clearance from fan to radiator.
View attachment 1263092

Do you think the smaller ‘89-‘90 Dodge fan would resolve the bypass nipple clearance issue on the radiator?

 

[Dirty Koala]

Do you think the smaller ‘89-‘90 Dodge fan would resolve the bypass nipple clearance issue on the radiator?

I am not sure of the dimension of the 89-90 fan, but if it is about .25" shorter then it likely would. That said, you still have no use for that nipple with a 6BT, so there isn't any need to keep it at full length.

 

[Will Van]

I am not sure of the dimension of the 89-90 fan, but if it is about .25" shorter then it likely would. That said, you still have no use for that nipple with a 6BT, so there isn't any need to keep it at full length.

Good point.


I wonder why Toyota included the bypass in the first place?

 

[Mr Cimarron]

I kept the nipple.

 

[Mr Cimarron]

I'm glad you have your build nicely organized. It will save me time digging through your tread as I will be copying a few things for my 75 build.

 

[Dirty Koala]

I'm glad you have your build nicely organized. It will save me time digging through your tread as I will be copying a few things for my 75 build.

I have been meaning to go back in and tidy up the indexing...there is a vubch of stuff that I did that I never added to the index in the 1st post...will tackle this once I finish getting through the @NLXTACY and @scottryana Turbo Kit thread.

 

[Will Van]

I kept the nipple.

Easy if you’re running electric fans!

 

[Dirty Koala]

Easy if you’re running electric fans!

Yes...but the cummins mechanical fan is a beast and moves a lot of air....about 8500 CFM when in full lockup...there arent any electrical fans out there that will push that much air.