T-Maxx model 4910 engaging problem

[Zdragon71]

I recently bought a used Traxxas t-maxx model 4910 2.5 which has had the 3.3 motor installed. The vehicle ran great for 3 days until i started not engaging into drive. When it first started it did it once and then it seemed to be slipping really bad and then it wouldnt engage at all. I took apart the tranny and found the pin holding the gears on the output shaft broken. So i replaced the pin and put the tranny all back together as the specs diagram showed. It still would not engage in gear. i then took apart the slipper clutch assembly and noticed that it is worn. can't really tell but looks about completly worn. I just now re asembled it all after tightening the slipper all the way and backing off 1/4 to 1/2 turn and it still doesn't engage. I have also checked the clutch bell and main clutch off the engine and it is all in tact and seems fine. I do have the slipper upgrade kit on order but i want to know if anyone knows for sure that is my problem or if I'm missing somthing. I've been back in the tranny twice now to make damn sure i assembled it back corectly.

 

[Snook Man]

I’m assuming you have the forward only conversion since you said gears on the output shaft, and the stock setup with reverse would have no pins on the output.
Look at the pin that attaches the forward and reverse primary (two smallest middle shaft gears) to the shaft. It too will break on occasion. Make sure the OWB in the largest gear on the primary shaft (1st gear) will rotate freely on the shaft and will grab the shaft when spun the opposite direction.

As for the slipper clutch, what shape are the friction pegs in the spur gear? If the slipper looks really worn, chances are the friction pegs and/or the spur gear needs replaced.

 

[Zdragon71]

The friction pegs are what look to be worn down completly and no forward only conversion has been istalled that i know of. The servo for reverse has been disconnected and the shaft it pushes into the tranny is pushed all the way in. I will check the other gears you mentioned and see if something else is broken. Thanks

---------- Post added at 5:35 PM ---------- Previous post was at 5:33 PM ----------

the new conversion kit comes with new spur gear input shaft and 3 friction pads and all the hardware. i should have it by monday.

---------- Post added at 5:36 PM ---------- Previous post was at 5:35 PM ----------

Also the friction pegs in my slipper are small and round

 

[Snook Man]

I’m pretty familiar with that transmission and a little confused at which pin you replaced. If you have reverse there are no pins that attach the bottom (output) shaft gears, they free float on the shaft and work as a centrifugal clutch with a pawl to engage the inner clutch bell that the shift fork slides back and forth for forward and reverse. (Shift fork rod pushed all the way in toward the tranny is forward, make sure the shift fork stays secured since the servo is unhooked)
The only pins in the stock 2.5 reverse equipped transmission is the 1 pin on the middle shaft and 1 roll pin on the input/slipper shaft.

Are you testing the transmission in the truck under power? You can not spin the spur gear fast enough by hand to engage the internal clutches when it is equipped with reverse.
If you have the transmission out and in hand you can test it by blowing compressed air on the spur gear.

 

[Zdragon71]

the pin I'm reffering to had broken and replaced is the one on the middle shaft, my bad. but i just now went back through the entire thing and see nothing wrong inside the tranny. So again I'm hopeing that its the slipper clutch being worn completely out. Also yes i have been testing under rpm and it seems just barely and vaigly trying to move if any at all. My slipper has the 6 round plates and the upgrade will have the 3 larger plates and a totally new input shaft assembly all together included. Whats your thoughts on the slipper being the problem? and thanks for the input so far.

---------- Post added at 6:21 PM ---------- Previous post was at 6:19 PM ----------

going to try the compressed air trick now

---------- Post added at 6:33 PM ---------- Previous post was at 6:21 PM ----------

Snook man THANKS! Now i am sure the tranny is fine the compressed air kicked it into gear and spun the drive shaft so it has to be the slipper clutch and mine should be here saturday or monday from Hobbytown usa. They said they would ship it out after the fuel tank i ordered came in today.I'm Stoked!

 

[Snook Man]

You are welcome...

The torque control slipper upgrade works well. The only draw back is there is the 72T spur gear that comes with the kit is the only size available that meshes with the clutch bell correctly with the stock setup. Due to the design of the slipper being wider than the stock slipper they had to engineer the spur gear to be concave so it would fit closer to the transmission and fully align with the clutch bell front to back.
Other than that it is a good upgrade.
I use it on most of my builds with some modifications to be able to run the revo mod 1 spur gears and 1/8th scale clutch bells.

 

[Zdragon71]

Nice lookin rig. I've noticed your responses on about every thred I've viewed and seems like you are very knowledgable in all classes. Thanks for all your input and as the money flows I fully intend on making the best upgrades possible.