T-90/Dana-18

[Mastiff]

I'll be pulling these from my Scout 80 while I have the engine out, to seal leaks at the very least. My 2nd gear was grinding for a while, but it seems good now. I wonder how difficult a rebuild is and whether I ought to just do it while I have everything out?

Does ihon have rebuild kits for these kinda like the ones from novak I keep hearing about? Their kits appear to include all the gaskets and seals plus common wear items (bearings, synchros).

 

[Robert Kenney]

Fairly easy to rebuilt the t-90. Some of the parts are difficult to find depending on vehicle vin. The 2-3 clutch hub and syncro rings to be specific. Iirc the earlier version is rare.

Places to watch are the input shaft to output shaft pilot bearing needles and bearing surfaces. If flat towed in neutral and with the transfer case not in neutral this point can be damaged.

The 2nd and 3rd gear clutching dogs especially 2nd gear can be damaged from grinding. Don't know if those are available new. Damage is clear as the points are 45*/side but will show rounding and significant shortening. That can cause popping out of gear.

The x-fer is also simple to redo and parts are available. The Scout d18 has the larger idler shaft with the roller bearing and fairly bullet proof. Setting up the input and output shaft roller bearing end play is the worst part.

Jeff has the bearing/seal kit, idk about the other hard parts. Probably need to call.

When you tear into it you can post pix and get our opinion on condition.

 

[Mastiff]

One place I'm sure I have a leak is from where the shaft comes through the front of the case underneath the input shaft. Is that fixable, or does it just come from wear on the case over time?