Zombie Slayer: DNE2 Overdrive Install

[UMR_Engnr]

My truck has a C6 and 4.10s so highway driving leaves something to be desired. I usually drive around the city so this isn't an issue, but with the IDI rally coming up (573 miles away) I was looking at my options for adding an overdrive. While surfing Craigslist, I found someone locally selling a TH400 Turbo overdrive for $150. From the picture it looked just like a DNE2. I went ahead and picked it up. Sure enough it is a DNE2, the TH400 adapter was cracked but I wasn't going to use it anyways. My plan is to replace my carrier bearing with this unit supported with a crossmember. There will be a short shaft between my BW1356 and the DNE2, and then a custom driveshaft to the rear.

Currently the BW1356 has a slip yoke, but I'm thinking I will add a fixed yoke, and have the slip be in the input gear to the DNE2. Since there will be little movement between the t-case and overdrive I think this will be ok. Having two slip yokes seems like a bad idea.

It should all fit, and will sit approx 3" below the frame rails.

So this is the beginning of this saga. Starting with the case broken open.

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Everything looks fairly serviceable, but I won't know till I get all the goop cleaned off. Anyone have any tips for quickly and easily getting all this gunk out of the case?

 

[DaveBen]

Your straight driveshaft will be good between the tranny and OD unit. No slip joint is necessary.

 

[icanfixall]

Wow is that ever a mess. Looks like someone NEVER changed oil in it. you might put it back together. Fill with atf. Find a way to spin it and let it spin for a few days. then drain off the old. Refill again and see how it looks after spinning it for a day.. Or use another type of oil. Getting to oil warmed up will speed up the cleaning too.

 

[UMR_Engnr]

I took off the shift mechanism panel first and was a little shocked. I expected the internals to look much worse, but they don't look too bad. Hopefully, it's not too worn.

 

[Hydro-idi]

Little dirty under there. I would steam clean it. That would clean everything 100% and remaining water would evaporate. Then oil it down & inspect for wear/broken parts.

 

[UMR_Engnr]

Steam cleaning. I like it. Any suggestions for a good steam cleaner?

 

[Hydro-idi]

They are expensive....at least the good ones are.
I would just take it to any machine shop and have them do it or ask to use theirs if you don't have one. Any engine builder should have that cleaning equipment.

 

[shawn deere]

Steam cleaning. I like it. Any suggestions for a good steam cleaner?

Use your dishwasher if your single. Or want to be. Lol

 

[UMR_Engnr]

I tried a McCulloch MC1275 steam cleaner and it did nothing. I gave mineral spirits a try and that is doing the trick on the small parts. A local machine shop said they'll clean the case for $45, but I need to completely break it down. There are a lot of blind bearings and bushings that I'd rather not remove, so I might just try soaking the whole thing in mineral oil and see what happens. Thoughts on if it will be a big deal if I put the four secondary shafts back in a different arrangement after I clean them? Do the bearings need to match up with the shaft they were previously on?

 

[UMR_Engnr]

When rebuilding boxes like these and transfer cases when should new bearings and bushings be used vs reusing the existing ones?

 

[tjsea]

When reassembling it make sure to time the gears. Dad has an old diagram somewhere of where they are to be timed at. It's kind of an odd timing arrangement.

 

[jayro88]

Wow is that ever a mess. Looks like someone NEVER changed oil in it. you might put it back together. Fill with atf. Find a way to spin it and let it spin for a few days. then drain off the old. Refill again and see how it looks after spinning it for a day.. Or use another type of oil. Getting to oil warmed up will speed up the cleaning too.

This is what I did when I got my DNE2, but it wasn't that dirty. I filled it with ATF and used a drill to spin it over. Repeated it a few times.

 

[UMR_Engnr]

I noticed the shift fork is very worn. Does anyone know if this was a standard part that was repurposed or is it custom for this box? If I can't find a replacement, I'm going to see about getting the pads welded up and reground.

 

[UMR_Engnr]

I don't think this motor is salvageable...

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[UMR_Engnr]

Here is a picture of the shift fork wear, and also some wear on the teeth that engage the shift collar.

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Based on the motor damage, I wonder if it didn't break mid shift and just grind the gears.

How serious is the gear damage? Is the unit still serviceable?

I did buy a NOS "Made in USA" motor on eBay, so I'm not worried about that part of it.