xtm monster mmt

[debo350]

any one have any luck getting the tranny to shift into second gear?:surrender:surrenderI had this truck for a month and just can't get it to shift. Any web sites out there I need help BAD!! or should I just give up on it, you can see this truck on hobbypeople.net web

 

[bnrpat09]

your car is shifting you can't hear it shift in this truck the mammoth is the same way its because it is more of a diff in the middle instead of an actual transmission!!

but if you just arent shifting period

try tuning it a little leaner if the engine is running too rich the truck wont shift

 

[olds97_lss]

In my mammoth, when it shifted, I knew it shifted, you could definitely hear it... as for your truck, I have never seen one run or even seen one other than pictures.

Considering the two speed parts listed for it are the same as the ones for the mammoth, I'd assume that you would be able to hear it shift as well. For my money, the mammoth was geared too tall. Good for speed, but for such a large truck, you needed one heck of an engine to get it rolling.

I'd suggest putting something under it and getting the wheels off the ground, then lightly apply the gas and see if you can hear it shift as you gently increase the engines RPM.

Does it seem really doggy off the line? Does it seem like it goes really fast but takes a long time? Or, does the engine peak out on RPM's and it doesn't go that fast?

 

[debo350]

it seems to go fast , but it takes a little time, and I've adjusted the trans a WHOLE lot of times with every figure a can think of, someone told me to try a cold plug? But a you said any two speed trans you will here the shift, but over all it does seem a little lazy because the truck weighs about 15lbs, but my MGT weighs 12lbs and its not lazy at all so what do you suggest!!

 

[olds97_lss]

Well, if it was stuck in first, it wouldn't be all that fast and it would hit it's top speed quickly. But, if it's shifting into second too early or is stuck in second, it will be relatively fast, but it will be slow to get top speed. What you can try is to screw the two speed adjustment screw all the way in. Not with a lot of force, or you will deform the spring. With it screwed all the way in, the truck should not shift at all out of first gear. So, it will be relatively quick off the line, but will hit peak speed pretty quickly. Then, if that works, adjust the two speed in 1/4 turns out until you get it to shift.

I liked the two speed of the mammoth for the same reason they are on other trucks (quick off the line, decent top speed), but it was too hard on the diffs. No slipper. I ended up swapping out the two speed with a center diff. Then I had to gear for a happy medium between top speed and quick of the line. But, my diffs lasted much longer.

A plug or tune will only affect your two speed if your engine isn't running right. If your engine sounds clean throughout the entire RPM range, it's something still with your two speed or your clutch. If your engine is running rich or lean, your not getting good power/RPM's out of it throughout the RPM range.

If your clutch is slipping, the truck will move slow off the line, but the engine will run a higher RPM that you can hear. A slipping clutch will make the two speed sound unnoticeable at times when it does shift. When it hits second, instead of hearing the engine drop RPM's, the clutch slips until the speed of the truck matches the RPM of the engine. You will find the same is true on trucks with a slipper clutch set too soft (which you do not have).

Sorry, I looked for a while to find a mammoth ST at least so you could hear how it shifts.

Go here and download the vid: http://www.rcpics.net/view_single.php?medid=76379
It's 12.7 meg in size.

At seconds 11-12, 28-29, 32-33, 42-43, and 47-48 you hear it shift. It shifts from 1st to 2nd a total of 5 times that I noticed in the vid.

Hopefully this will help you gauge what's happening with yours as well.

 

[debo350]

I had it out yesterday and the same thing, what I did notice is that if I hold the truck on the ground and give ity throttle it will hardly move , and know that you said the clutch might be the problem it made me think, that,thats what the problem is. I have a set of losi clutches and I'll throw them in and see what happens, and check out the old ones, I should have known that they wouldn't give you a good set of clutches in a ready to run.

 

[jon2]

Sounds like you really are running too cold. Have you broken in the engine? You Don't try tuning for speed till you have broken in the engine properly.


Let us know

 

[debo350]

The engine was broke in properly, but what I'm seeing really is a carb problem, I'm going to change it today and seal up the whole engine,I'm really thinking of getting a LRP 28 and junk this bomb, but I'll let you all know Mon. evening

 

[olds97_lss]

XTM engines used to be pretty good... the 24.7 was their flagship engine for a long time. 5 years ago or so, it was the engine to have if you owned a savage. At least for a basher. That was before everyone and their brother were making .26+ engines for off road RC.

 

[debo350]

I found the problem thanks to olds97-lss, it was the clutch shoes worn beyond the point of no return, changed the turned the set screw all the way in, tured back out 3 turn shift flawlessss, thanks to everyone out there that helped me, and a BIGGG shout out to rc nitro talk AAA+++++++++++ members!!!