O123456789

Hi,

Iam trying to troubleshoot an issue with my TMaxx and would appreciate any help / suggestions. Iam somewhere between a novice and a noob so if some of my terminology is wrong please don't hold it against me.

WhatIhave:
Original Tmaxx .15 with forward/reverse transmission

Issue:
The Tmaxx does not move when Igive it gas.

When Igive the tmaxx gas Isee bell clutch thing on the motor spin, which spins the spur gear.Ibelieve the slipper clutch is fine since Isee the drive shaft attached to the spur gear spinning. Ihave taken apart the clutch and inspected the shoes which appear to be fine. Itook apart the transmission to see if anything looked wrong, like stripped gears. Everything appears to be fine, soIam not sure what else to look at or look for.

Itried to talk with an employee at my local hobby shop but he didn't seem to want to waste his time talking to me. He just said bring it in and he will look at it. Since Iwould like to understand how the truck works, and more importantly how to fix it myself, Idon't want to become dependant on someone else fixing it when it breaks.

Any suggetions would be much appreciated.

PsyCho DaDDy

So blown diff ?
Not meshed correctly, cogs ?
Snapped tail shaft ?
Snapped uni joint ?

Jurgen1

so when you give it throttle the clutch bell and spur spins do the axles coming out of the trans spin ? did you check  the one way clutch inside the trans and make sure its locked on the  shaft   check the pin to make sure the gears are on the shaft .

O123456789

Hi Jurgen1 (or anyone else who may have ideas),


With the tires on the ground the axles didn't spin,Ididn't try it with the wheels off the ground or with the axles detached. Currently the transmission is out of the car, as took it apart to see if anything seemed out of the ordinary. If Ispin the spur gear with my finger, sometime the axles coming out of the transmission will spin, as quick test Iused a stand alone eletric motor to spin the spur gear and the axles do spin.

For reference which item in the exploded diagram is the one way clutch ( is it item 4988 ). In the pdf from traxxas my transmission has the "old style" primary shaft assebmly.
http://www.traxxas.com/PDF-Library/4...o15_tranny.pdf


MoreInfo:
It "seems"to me that the rotation from the motor and spur gear is not getting transfered to the axles. Ilooked at the output gear assembly (item 4997 +4998)and they "seem" ok. The little metal thing(black pawl/ shiny pawl) on the gears swings out when Ipush on the one side of them. It looks like that is how the 4990(transmission clutch bell) gets engaged to spin the axel. How does one know if the output gear assembly is behaving correctly?

Thinking outloud:
Iguess Ireally don't know that the clutch bell on the engine is engaging correctly. It is possible that even though it is spining it could still be slipping and not giving enough rotation to the transmission (spur gear) for it to engage. How does one verify the engines clutch bell is being properly engaged?

steed2-inactive

those early t maxx,s have a clutch on the output shaft inside the transmission. could be a problem there?

O123456789

Hi steed2,

Do you have any ideas/suggestions on how to troubleshoot the output shaft?Since all the gears and parts "seem"ok it is hard for me to know what to look for, besides just replacing parts until it starts to work.

Mclovin350z

I would take it all apart and clean anything that looks important except the gears. There is a one-way bearing in there and if I'm not mistaken at least 2 pawl type clutches. I would get a forward-only frst if you're going to throw parts at it.

O123456789

Hi (Mclovin350z),

Ihave taken the transmission apart a couple times now and after this last time it seems to be behaving differently then before. Iam also looking at a FOC(forward only conversion)since there seems to be less stuff to go wrong in the transmission with this conversion.

I posted my issue on two forums, I got some suggestions on the other forum and will post my results here as well.

Test that engine is properly engaging spur gear:

Action: Hold spur gear while I giving the car gas.
Result: I had to give the car a fair amount of gas to get the spur gear to spin (while holding the gear), but it was able to spin the gear. I would say I was using more then slight but less then vice like pressure on the spur gear. I did get a little cherry burn on my figure.

Test if transmission is being engaged.

Action: Pick car off ground and give gas
Gentle Gas:
Result: I don't hear clicking just the motor spinning, and the tires do not move.
More Gas (1/2 throttle maybe):
Result: I can't say I hear clicking but the tires did spin. With the car off the ground I kept giving it gas until the wheels finally spun. It was sort of a jerking spin, then after a sec or two the wheels spun at a consistent speed.

Since the wheels spun this time I figured I would try to put it on the ground and see if it would go. Again I had to give the car a fair amount of gas for it to go, it was slow/sluggish but did move. I tried both forward and reverse and both seem to function.

Note: It has been a long time since I last drove it so I don't recall how responsive it was when I first got it. Maybe it is behaving normally now and I just don't know it.

Mclovin350z

If it will move at all then try to TIGHTENthe slipper clutch, just a little bit.

O123456789

Hi (Mclovin350z),

Ihave my slipper clutch a little tighter then recommened by traxxas and Istill have the same issue. Someone on another forum suggeted Ilook at my throttle linkage, which was a little off. Imade some adjustments but the car is still slugish. When my car initally broke (a long time ago)Iam not sure it was fully broken in. Iwonder if the behavior Iam seeng now is the result of an untuned engine.

dea.racing

My Feedback: (60)

did you ever solve the problem?

O123456789

Sorry didn't notice the reply.

So I think I know what happened with my TMaxx.

When I took apart the transmission and clutch bell I fixed an issue with my transmission and induced an issue with my clutch bell. I think my transmission was probably stuck in between forward/reverse and taking it apart and putting it back together got everything back in sync. When I put my clutch shoes back on, I did so referencing my operations manual, which states to put the shoes with leading edge engagement. When I looked at the online manual it states to put the shoes with trailing edge engagement (step 28) (http://www.traxxas.com/support/index...n&suchbegriff=)

After switching my clutch shoes around the car seems more responsive to throttle. I drove it around a bit and broke a few teeth off my spur gear. I read around the forum and I am guessing my motor likely shifted. So I am off to buy some light thread lock

Radioman193

Adjust the grub screws on the fwd output gear and it will kick in at a lower rpm

O123456789

Hi Radioman193,

Ihave since switched to a FOC transmission, but when Iput back in my stock (forward/reverse)transmission Iwill give that a shot.

Thanks