D21 FS5W71G gearbox upgrade?

[Datsuntech]

Bear with me as I write a book...

A few years ago I picked up a Japanese 1992 4dr D21 Nissan Datsun, TD27T, 5-spd 4x4. Soon after I got it I noticed a bad noise from the front of the trans. When I took out the trans the input shaft seal had failed and the input shaft bearing was toast. While tearing it down I found that the needle bearings in the input shaft were pitted and had wrecked the input shaft and the end of the mainshaft. Rather than replace all of that I found a rotted truck with a bad engine but a newer rebuilt trans in it. Being from a Z24 powered truck the case front had to be changed to fit the diesel. I took the trans apart inspected everything replaced the seals and gaskets and put it back together with a new clutch.
All good...
Fast forward to a few weeks ago I'm on the highway and bang! No 5th! Crap Ok try 4th, yup that works slow down some more, no 3rd...
All I have is 4th/direct no other gears or reverse. Well 4th got me to my destination but when I stopped I noticed oil coming out of the bellhousing so the input shaft seal is toast again and most likely the clutch. I haven't had time, nor desire to pull this trans to see just what went wrong but this is the second trans on this truck with only a little over 130,000 kms. I use this to tow my camper and my cars around on a car trailer. When the trans blew up though I was unloaded and just cruising along.
I write all of this to ask. Has anyone upgraded the trans on the back of the diesel? FS5R30 from a V6 Pathfinder?
I have never blown up a FS5W71 in any of my 2wd trucks or even in my 510 that I drive the crap out of, but this truck continues to eat transmissions.
Suggestions??

 

[Datsuntech]

Bump for attention...

 

[bods]

Hey mate. Didn't see this earlier, plus I'm not sure who if any of the older guys that used to be around on here with experience with the td27 are even still around....

From memory though, and I'm sure someone will correct me if in wrong, I believe the fs5r30 is in the zd30 and yd25 D22 navaras. I don't know if any issues with them, I know the patrols had problems breaking the 5th gear cog if towing under excessive load, but I'm not sure what model gearbox that was with those problems.

Whether or not a fs5r30 bolts up to a td27 I could not say, I'm not even sure if there are any service manuals floating around on here anymore that may have had exploded diagrams so you could compare them.

I don't know if that is of any help to you, but good luck...