Dana 18 Small Hole To Large Hole Conversion

As most of you likely know, the T14 transmission is not compatible with the small hole (3 5/32") version of the Dana 18 transfer case due to the size of the T14 bearing retainer (4"). What's a guy do when he has a nice small hole Dana 18 and can't seem to find a large hole version?

Had to take light passes due to the interrupted cut where the oil passages are, but it turned out nice. I'll get an after pic with the bearing retainer installed and post it up, but it is pretty much a dead ringer for my other large hole Dana 18 now.

 

Be very careful doing this! I tried it once, behind a T15 and wound up breaking the mounting ears off of my transfer case. Turns out the counter shaft and reverse idler shaft protrude out the back of the transmission case a little bit further on the T15, and it was enough to break the transfer case. The recesses in the transfer case are larger on the big hole case where those two shafts go.
I'm not sure if you'll have the same problem with the T 14 , just a word of warning...

 

Thanks Doug, I will double-check that pocket depth where the transmission shafts and lock plate go and post an update.

 

Hey, that's cool!

 

That's what milling machines are for! Nice job.
-Donny

 

Okay, good heads-up play Doug...the pocket on the small bore case was shallower, but only by .020". I suppose that could be a difference in casting too, but slightly different none-the-less. However, when it comes to the T14, there is still plenty of clearance for the two shaft ends (.060"). So, I think we'll be good.

Here are a few more pics of the "finished" product (I still have to dress the edges a bit from the boring, clean and paint)....

Bearing retainer installed...

I will update this post once it is all assembled to verify all works as anticipated.

 

Are you gonna mill the intermediate gear for some tapered roller bearings?