Hi all. New to forum old at r/c. I have an NMT2 with 18SS, THS pipe, MS filter and other mods. I stripped the rear diff gears even after shimming. Bought the steel gears from TOWER, but they do not have the pins that hold the spider cross shaft in place. put it together anyway, and now it turns rough and locks up. what can I do what parts do I need? Great truck, great engine want to run it bad. Very good forum. Thanks for your help.

I toyed with the notion of building what you have at length... I'm sure it's a blast....

That said...

Look in the HPI manual (if you don't have it, they have all manuals on their site) for the HPI part#, look for a Master blow-up and the number it carries will match with the part# on a list. Once you have it you can plug it into Tower's search. I don't know what it is, but you can search for a string like hpi gear and get 50 results. The gear you need invaribly will not turn up. If they don't stock it they can order it if you call them with the HPI part #. Your local hobby shop can also order it.

Thank you FROST I already have a set of steel diff gears from TOWER. But the old alloy gears had pins cast on them to hold the cross shaft in place. The new steel gears do not have the pins, and it appears to let the spiders move around and cause binding. It is a blast to run. Insanely fast and handles great. But its sitting on the bench till I get the diffs fixed

Crash:

I have a whole bunch of similar mods to my MT2. I just regularly change out the rear gears, but someone posted on the Official MT2 Thread that you can add spacers to push the gear into the spider gears:

Here's a link to the part:
http://www2.towerhobbies.com/cgi-bin...?&I=LXBTA4&P=7

and a pic of where to put them:

Thank you Grantothismo, good diagram, I actually solved the problem by installing shims on the cross shaft between the housing and the spider gears. The spiders were apparently rubbing on the diff housing. Seems the pins on the original gear help to locate the spider gears toward the center of the diff housing as well as hold the shaft in place. I used some small thin washers I had in my parts box. The new steel gears are very smooth now. Thanks to all who replied to this post