Trucks Help With My 2.5 Tmaxx

Charlie88

New Member
So long story short I just completely tore down my dads tmaxx and cleaned/rebuilt everything. Now that I have everything back together I’m having issues tuning it. I put the carb to factory settings and it was running filthy rich, after messing around with it on the bench it seemed to be idling alright. Out in the yard we go where it still seemed to be running rich but I’m nervous to lean it out anymore because it already seems too lean according to the carb settings (2.5 out on the hsn and maybe .5-1 out on the lsn). Still revs to the moon when pinching the line off to the carb before dying and of course it smoked the slipper clutch in the process of running around the yard so now I’m at a stand still.

any tips or advice would be much appreciated, still fairly new to nitro and this truck is starting to push me away.
 

Tony

Staff member
The low speed should be pretty much flush with the face. When you pinch the fuel line, it should take 3 seconds to die. Any longer and it's too rich on the bottom, any less and it's too lean.

Tuning the high speed needle should be done with a temp gun for best results. No more than 240ºF at the glow plug.

When you say slipper clutch, I think of the slipper that is attached to the spur. Is this what you are saying was smoked? If so, then it's too loose. The slipper should be adjusted so that you do not spin the wheels until about two feet after you went WOT. Then it should grab and launch.

If you are referring to the clutch that is inside the clutch bell, either the idle is too high (which is what I'm thinking) or you were bogging it down too much. Try adjusting the idle and don't use part throttle as much unless the truck is rolling.
 

Charlie88

New Member
Thanks for the response tony, I just came in from messing with the truck again after replacing the slipper clutch assembly (spur gear). I’m assuming it was too loose cause the plates were blued and it melted the middle of the spur gear. I started over with tuning and got it running pretty good at least at idle and slight throttle.

The problem I’m having now is it seems I have to rev it up higher then normal for it to actually move. When it does it’s making a chattering noise and I can actually see the spur gear stop and start spinning again almost like it was spinning the opposite way before it engages. After letting the motor run a little bit I brought it back in. I didn’t want to ruin another spur gear not knowing if maybe I have a tranny issue or not.
 

Tony

Staff member
The chattering you are seeing is caused by part throttle application and it is the dog slinging out, hitting the pin inside the transmisstion in the 1-2 gear set which causes it to reverse which you are also seeing.

The slipper can help this, but if this is happening at only part throttle, it is normal.

One of these days I will finish the T-Maxx videos and the slipper adjustment is one of those that I need to get done.
 
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