Tranny/Transfer compatibility (1 Viewer)

[DickM]

As part of the tub swap/complete 2F rebuild, and more for my (mostly) 78 40 series, I finally bought and built the Orion transfer case that I have lusted after for years. The "4 speed case with 3 speed gears" was tired and noisy, and was depositing a good bit of metal in the gear oil.

Ands as these things go, I saw a rebuilt H41 in the MUD classifieds. The existing H41 was in about the same shape as the TC it was mated to. It had been bought used/inspected from SOR about 10 years ago, and has served me well, but in the last couple of years, shifting up or down into 2nd gear required a vigorous double clutch. The gear oil when I drained it to pull it had a "lovely" golden hue, with an impressive mound of metal sludge on the drain plug magnet.

So, after confirming that the for sale H41 had a 10 spline input and a new 16 spline output, I did the deal, and had the new drivetrain of my dreams.

Or not.

The one-piece Orion will not physically mate to the new H41. The transfer case side of the existing H41 and the just purchased H41 are completely different.

New H41

Old H41

After bunch of swearing, and some research, I am still not sure how I ended up where I am. The new tranny obviously needs a split case transfer case, but I thought that the later H4x transmissions that mated to split cases had 19 spline outputs. The output on this one was changed, but why 16 spline? What transfer case would you run behind this tranny? And more importantly at this point, what options do I have to get to where I need to be?

Thanks for any insight you can give.

 

[DickM]

From Advanced adapters website:

August 1980 to 1989: In August of 1980, major drivetrain changes occurred in both the FJ40 and FJ60 models. The transfer case design was changed to a split-case configuration with a 19 tooth internal spline on the input gear. The low gear ratio was 2.27:1 in these transfer cases. There are three different models of this transfer case; however, the differences are very minor. The transfer case adapters we offer will work with all three models. Click here for Low gear options for this transfer case. TLC 19 Spline 1 TLC 19 Spline 2

 

[Toyoland66]

Looks like your new transmission doesn’t have a back plate on it. It looks like the one from your old trans would bolt up except for the bottom bolt.

 

[DickM]

Looks like your new transmission doesn’t have a back plate on it.

Well, I believe you have solved my problem. A quick look at SOR shows 2 versions of back plates, a 3 bolt and a 2 bolt.
While I have removed and installed several different trannys, I have never seen one with the backplate removed, so, to be honest, it never occurred to me that the backplate wasn't part of the case. DUH!
One thought that went through my head was about needing an adapter to make things work, and you have pointed me to the one Mr. T already built.
Thanks a bunch for the help.