Help new motor and some problems

[lightningsti]

Hello,

I am trying to get back into the hobby, so I picked up a used 2.5 tmaxx with forward only conversion and siro .18 motor. The truck ran great when I picked it up, the motor did not last too long, but what I have gathered from this forum is that was not a very good motor. So while the truck was down I gave it a very good cleaning, took the whole truck apart and cleaned and regreased it. The new motor was a 3.3 traxxs motor with the ez start, it was used but in very good condition. Put the truck back together and installed the motor. The motor started right up, no problems and sounds very healthy. My problem is the truck only goes in reverse, what did I do wrong? Thanks for all the help

 

[novaone]

I don't have experience with the 3.3 so this might be a wild guess but if they left the idler gear in the transmission when they did the forward only conversion and you installed the forward only gear (the one that has the drive shaft ends on it) backwards that would do it. Not sure if that's possible.

oh I just thought of a way to test my theory. Since you have forward only the large gear on the transmission only free spins one way. If it free spins one way and when you turn it the other the truck goes backwards this is probably your problem.

 

[lightningsti]

Thanks but the idler gear has been removed. Could it be possible that the differentials are backwards or upside down?

 

[Tmaxx96]

could be your differentials but it could also be you engine running backwards take your ez start off flip the one way bearing then reverse your ez start motor wires

 

[Metalhead Matt]

could be your differentials but it could also be you engine running backwards take your ez start off flip the one way bearing then reverse your ez start motor wires

Woa little buddy. Go take a time out. Before you do all that, find out what way the engine's supposed to turn. I haven't paid enough attention to know; someone will. Also, the small print on the owb should face towards the motor. But if your power wires are hooked up correctly to the ez start, it's not running backwards. Let some others chime in with some more knowledge on the subject.

 

[Tmaxx96]

good point but the engines are supossed to turn clockwise to go in forward so if you engine is running counter clock wise then do what i said

 

[lightningsti]

good point but the engines are supossed to turn clockwise to go in forward so if you engine is running counter clock wise then do what i said

Clockwise when looking at the back of the motor or looking at the front of the flywheel?

 

[traxxas t-maxx]

My 2.5 did that and all I had to do was flip the clutch shoes around.

 

[Beddo]

Clockwise when looking at the back of the motor or looking at the front of the flywheel?

Clockwise looking from the back of the motor, so looking from the EZ start end, the flywheel should be running clockwise.

Like someone said, check the writing on the OWB is facing toward the flywheel.

It sounds more likely that you have done something wrong in the transmission rather than the engine. Nitro engines dont like running backwards at all and it would be stuttering all over the place.

 

[lightningsti]

Supposed to be doing work at work but I am sitting goofing off. I think it is the diffs are in upside down. The motor spins the trans in the correct way, what I mean is that if the motor was spinning in the wrong direction then only the slipper gear would spin. So the motor spins corectly and engages the foward only trans that turns the output shaft clockwise, but since the rear diff is upside down (the large gear is to left of the center driveshaft) the truck wants to go in reverse. So tonight when I get home I will try and turning around the rear diff so that the large gear is to the right.

 

[Metalhead Matt]

Sounds like a plan. Is your rig only 2wd? The part that had me thinking was that it would be a heck of a coincidence to put both diffs in backwards. Very possible, though. It's an easy mistake to make. Let us know how it turns out.

 

[surgemaster1970]

You cannot fit the diffs in the bulkheads upside down without them being at an angle impossible to get the driveshaft on if you can fit it all together and you cannot fit them backwards either they work both reverse and forward for the front and back the same way and are the same units;-unless you totally dis-assembled the diffs too..Most of the T-maxx driveline and suspension parts work for front and rear except for the bulkheads...All my engines in my trucks / cars spin CCW when running;- staring at the flywheel.......

From what I get from this thread is the truck is driving backwards after installing a new engine and doing a good cleaning..Thats all?


The only thing I can figure vas the totally logical explaination is if you totally disassembled the differential units you put them together backwards like you guys think....Attention to detail plays an important role in dis-assembly....Good Luck with the outcome..

 

[lightningsti]

Yup the rear diff was in backwards, turned it around and now truck goes foward with no problem.