power454

I just got my tmaxx 3.3 back from the hobby shop where the tech and I worked together and replaced the forward and reverse gears on the output shaft, the clutch, and gave it a tune up. It ran great for having a slightly broken front lower control arm. I bring it home finish putting the roll cage and other smaller miscellaneous parts on and clean it up. I took it out for the first time today after replacing the lower control arm and it started out running ok because I was being gentle and trying to work the clutch in. I started going a little faster and couldn't make a turn. I put it in reverse and then back in forward and the engine just raced and either barely moved or didn't move at all. It runs slowly in reverse if at all. Everything seems to be tight but no matter how much I rev the engine it doesn't go anywhere again. This is the third time in 3 runs that i've had this problem. Does anyone have any idea what the over all problem might be? If disassembled and reassembled the trans way too many times lately and don't see any problems. I checked every gear, bearing, and shaft and everything looks either new or in great shape and the hobby shop tech agrees. I'm about to sell this sucker or trade it for an emaxx!!!

JLRevo

Question one how much did the hobby shop rob you for 20 minutes of work. Question 2 Do you still have opti drive in.? If so remove asap and see what happens.

power454

Answer 1) they charged me $60 for parts and nothing for labor because I was helping do the work except for the tuning which i'm still learning how to do. I replaced the clutch and spring assembly, forward and reverse gears, wiring for my ez start, and a 3 channel receiver. The parts for the actual initial repair were like $30 of that.

Answer 2) I don't have opti drive on my truck.

I can't believe that the clutch would wear out in the matter of 10 minutes of running and most of that was tuning and what I call very gentle running. Meaning driving mainly in circles warming it up at slow speeds. Right now it's sitting on 2 car jack stands awaiting itsfate because i'm half tempted to destroy it with a forty pound sledge. I'm really about to walk away from rc because every time I run this truck I end up spending another $60-$100 for little stuff that's built like crap! And I usually upgrade when I replace something unless it doesn't make sense to upgrade it. Sorry this is just frustration talking now!

matts6887

Well, it is possible that ur clutch could have been bad right out of the box; as these days, quality control is not what it could be compared to back in the 80s...I would call traxxas though and see what they have to say about the situation at hand.....

dirtpile

First things first. What is or isn't spinning? Have you checked the slipper? How did the output gears look? Have you checked the operation of the forward/reverse servo?
You could also try rolling the truck back and forth a couple feet by hand and see if that changes anything, especially after switching forward/reverse. Let us know.

power454

The clutchbell, spur gear, and the gears on the shaft that meshs with the output shaft are all spinning but the output shaft does not move. The output gears were replaced at the hobby shop when it was tuned and running great. I tried giving it a little push and it moved slightly on it's own for 1 second. Reverse is no better. being that i'm an ex car mechanic i'm kind of ahead of the gameso i'm sure it's something in the trans but that has been torn down and rebuilt 3 times since I bought it including both cases, all bearings, output shaft, forward and reverse gears, sleeve that goes behind the forward gear and the big gear on the intermediate shaft. I'm all out of ideas with this one. It just seems like the trans is stuck in neutral and moving the selector shaft on the trans even manually doesn't do anything. I have an upgraded servo for the trans. I just don't understand how in 10 total minutes of running how it could all of the sudden stop going forward or in reverse when the hardest I ran it was to do a 2 inch jump at quarter speed???[:@][:@][:@]

TMaxxDriver

hmmmm... sounds like you are in a bind there power454.... let me ponder for a sec and see what i can pull out of my cranium....[sm=bananahead.gif]



[sm=idea.gif] OK... How 'well' is your spur gear meshed?? I had the same problem, jump something small, and then it doesnt wanna move... Problem for me was, my engine mount screw were a tad loose and the whole engine shifted... everything would still spin, but wasnt meshed good enough to make it move... reset the mesh, and re-tighten the engine mount screws...

another thing i would try, is rip the clutchbell apart and check the shoes in your clutch... they may be OK when you tear everything apart, but when put back together, it works ok for a min, then decides not to work. the shoes could not be 'biting' like they should... maybe the spring is not on right??

last but not least, maybe something in the tranny. but you are sayin it has been re-built 3 times... that shouldnt be the problem, but quite possibly could be... spray it out with some compressed air, go over every tooth with a magnifying glass, could be something stuck somewhere that maybe you cant see... if all else fails, you can find one on ebay, (a tranny), DIRT cheap, $15-30... I can understand your frustration, I had a similar problem not too long ago, but mine was simple and ended up being the engine mount/spur gear mesh...

and if you STILL cant succeed... strap the C4 to it, BUT take a video!! Good luck man. let us know what happens... I wish i could help more.

dapro

Pull the tranny, and get out your parts explosion, and dismantle it...

I would bet you don't take your car to another mechanic do you?

When you put it back together the chuck a drill on the input shaft and experiment

dirtpile

I'm with dapro on this one. It's not an electrical problem so a careful inspection and some working knowlege (Which it seems you have being an ex-mechanic) will certainly reveal the cause. And use the parts explosion particularly for the location of any teflon shims. I had to replace a few gears in my own (old pro.15) trans due to one of those once.

Let's go over the scenario just to be sure. With your Maxx running you hit the gas and it doens't move. The spur gear spins like it should but the output shaft doesn't, meaning you have no power going to the shafts/diffs/wheels, hence it just sits there.

Assuming this is correct (And that the slipper clutch is OK.) narrows down the suspects greatly. It's definitely in the trans and there are only three parts in the trans that can affect both forward and reverse. One is the output shaft itself, but you just had that out and likely would have noticed that the shaft drum were worn/stripped/damaged so we can skip that one. The other is the one-way bearing on the intermediate shaft. If it's slipping you aren't going anywhere unless you get it to shift into second gear and keep it there. I would start there. If it checks out ok then move on to the third part. The pins in the forward intermediate gear and input gear, but this would be hard to miss too if youv'e have the entire trans apart..

And if you do find a problem with the OWB you might want to replace the shaft as well.

matts6887

From the sounds of things; I definitely agree here, that its gotta be something inside the trans; like dapro and dirtpile mention; tear that sucker apart again using the parts diagrams and have a look see; to see if u can possibly spot something that might look out of place or damaged/worn or otherwise in disrepair....

power454

I jsut replaced the transmission output shaft and the forward and reverse gears on that shaft as well as the bearings. Is there a 1 way bearing on the intermediate shaft in the trans? That would be the only thought that I can come up with. The slipper clutch beads were replaced just recently and it's tight. I can see the spur gear spinning and the intermediate shaft spinning on the front of the trans but the output shaft of the trans is not moving at all.

t-maxxmaniac

probly put the trans together wrong .......it happens its easy 2 do...

dirtpile

Hold on a tick. I don't think the intermediate shaft sticks out on the 3.3 trans. Your trans isn't black by any chance?

In case you're mistaken about whick shaft is sticking out (the input shaft does) then I'd look at the one-way bearing and the pin in the forward primary gear (it's held in with a c-shaped clip that may have come off) The OWB is in first gear (the big one) It's possible that it's sticking for some reason and somehow got unstuck when you had it apart, thus making it work fine for a while until it started sticking again.

If you have the black trans (where the intermediate shaft does stick out ) and it is definitely spinning then your OWB is likely fine and the problem is in either the pin/screwpin in the forward primary gear or the shift drum

TFancher

I had a similiar problem with my used truck right after I got it. Ended up being a problem with the
the gears you take out when doing the Forward only Conversion. That's the best $12 I ever spent
on the truck. Runs flawlessly now. Throw all that reverse and opti-drive crap out of the tranny and
put in the FoC and I bet you'll problems will be solved.

matts6887

Well yea the problem(s) will be solved, UNLESS like some others; ya want to KEEP reverse because it can come in handy in certain situations....

TFancher

Reverse is way overrated. [sm=drowning.gif]

power454

It must be the one way bearing on the intermediate shaft is going. I do have the black trans where the intermediate shaft sticks out. All clips, gear teeth, bushings and bearings are in great shape if not new. So that leaves the one way bearing that I didn't know about! Thanks guys! I will tear that sucker down again and replace the intermediate shaft and everything on it.

TFancher

Look at the center of your gears for wear. The center on one of my gears was almost ground in half.