Anyone replaced a LT230 Transfer Case?

[TerrorFirma]

Question: I am replacing my LT230T (28D 1988 model from behind a 5 speed manual) transfer case with one from behined an auto (14D 1984 model) and have discovered that the output shafts from the gearboxes have a slightly different spline?

On the 5 speed they are the same width but are angled across but on the auto they are the full square type. Now I am just about ready to slide on the new xfer case but doubt the mating compatability. Has anyone come across this and how have you remidied it?

JTO

[Bush65]

The LT230 input gear slides straight onto the mainshaft of manual gearboxes.

The ZF auto uses a spud shaft to adapt the LT230 to the auto mainshaft. There are 2 different spudshafts (see pic below). The early ones have a shorter splined section (top of pic). The length of spline inside the LT230 input gear was increased (and cross drilled for better lubrication) to overcome a problem with spline wear. This gear requires a different spud shaft with longer splines (bottom of pic) for the ZF box.

Apart from the length of the internal spline in the LT230 input gear, all model LT230's have the same 10 tooth SAE parallel side spline form (BTW same spline as the 10 spline rover axles).

Edit: The mainshaft on manuals is waisted where the spline length finishes and is not different for the later input gear.

The form of the splines on your gearbox mainshaft should look like those on the pictured spud shafts. If the sides of the splines are not parallel, they may have suffered from the dreaded wear problem. Your post said they are
angled across, I am not clear on what you mean by this. If they are badly worn, you will need a new mainshaft $$$.

[TerrorFirma]

Bush65,

Yes the splines are worn somewhat and dont fully look like the ones in your pictures as mine has a threaded section at the end of the shaft.

At this stage I am bouncing between just putting it in and getting the safety cert and rego and then do the replacement to the auto or just doing the auto replacement now while its all apart. The output shaft splines on the auto are in smick condition.

JTO

[Bush65]

Bush65,

Yes the splines are worn somewhat and dont fully look like the ones in your pictures as mine has a threaded section at the end of the shaft.

...

JTO
The pic shows the comparison between the early and late spud shaft for the 4 speed ZF Auto, not the mainshaft of a 5 speed manual.

The only similarity between the ZF spud shaft and the mainshaft of a manual box, is the spline form (10 tooth SAE spline).

Wear of the spline on the mainshaft/spud shaft and the input gear of the LT230, is a well documented problem, that will eventually result in no forward or rearward motion.

This problem is overcome by improving the oil lubrication of the splines, by providing cross drilled oil holes in the hub of the input gear. You will find much information in past threads in this forum. Rover has replacement input gears that have the cross drilled oil holes. Note that there are different input gears (number of teeth, tooth pressure angle, tooth width etc), depending on the version of LT230.

For a ZF auto, the spud shaft with the longer splines, must be used with the cross drilled input gear.

Cross drilled input gears are not available for some early LT230's. For these, you would have to drill your own (using special drills for the hardened material which the gear is made from), or there is an oil feeder plate available the help the lubrication.

Do not grease the splines at assembly, as this will not allow the oil to properly lubricate the splines.