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View Full Version : somewhat bullet proof jato tranny....


whitrzac
06.29.2009, 01:26 PM
the pinions are 28/18...

you MUST use the stock lower shaft and file off the raised part, or drill the correct hole in the 1 speed shaft to use the 2speed diff idler gear gear...

the mod takes ~ an hour, most of the time is spent fine tuning the endplay in the bottom shaft...

make sure to use the corect pin for the plastic gear:whip::cry:

http://i272.photobucket.com/albums/jj182/whitrzac/jato/IMGP4996.jpg
http://i272.photobucket.com/albums/jj182/whitrzac/jato/IMGP4995.jpg
http://i272.photobucket.com/albums/jj182/whitrzac/jato/IMGP4997.jpg

Metallover
07.09.2009, 04:38 PM
So are those two metal gears you put in the gears that strip? Which one in particular?

whitrzac
07.09.2009, 05:20 PM
So are those two metal gears you put in the gears that strip? Which one in particular?


the lower plastic one that drives the diff, it striped out the pin...

I didn't have the right pinions, but if you find one the size of the top gear in the 1 speed(15t??), it will be alot stronger...


you cant use a modified 1 speed lower because it moves the pinion too close to the diff when you flip it...

Metallover
07.09.2009, 05:47 PM
http://i345.photobucket.com/albums/p382/metallover1/tranny.jpg

So we have gear A, gear B, and Gear C. We also have pinhole 1 and 2.

By my understanding pinhole 2 is the first to go? And gear A and B strip too?

Gear A is in fact 15t, I have a 16t pinion that was just too big and fit real tight. Gear b is something around 20-22 teeth, didn't take too much time to count.

whitrzac
07.09.2009, 06:38 PM
http://i345.photobucket.com/albums/p382/metallover1/tranny.jpg

So we have gear A, gear B, and Gear C. We also have pinhole 1 and 2.

By my understanding pinhole 2 is the first to go? And gear A and B strip too?

Gear A is in fact 15t, I have a 16t pinion that was just too big and fit real tight. Gear b is something around 20-22 teeth, didn't take too much time to count.


gear A is the first to go, and usualy takes part of B with it,

I filed the shaft from the origanl 2 speed down to 5mm all the way accross to be able to flip the pinion the other way

you could use the 1 speed gear if you cut the larger portion off, and bore out half of it so the setscrew of the pinion will fit inside

http://i272.photobucket.com/albums/jj182/whitrzac/jato2spped-1.jpg

Metallover
07.09.2009, 09:40 PM
Awesome! Thanks for the info... I think if I blow A or B I'll get a 15t pinion to use for gear A and see how long that holds up.

Are the diffs/output yokes good stock? I have to assume...

whitrzac
07.09.2009, 09:47 PM
Awesome! Thanks for the info... I think WHEN I blow A or B I'll get a 15t pinion to use for gear A and see how long that holds up.

Are the diffs/output yokes good stock? I have to assume...


do it now, cus when A goes it takes B with it...

J57ltr
07.12.2009, 12:37 PM
So does this keep the 2 speed function? I am thinking of putting a Jato tranny into my HB lightning 10 specifically for the 2 speed. Are their any other problems with the Jato trans? I know I will need to have the mechanical brakes.

Jeff

whitrzac
07.13.2009, 08:28 PM
So does this keep the 2 speed function? I am thinking of putting a Jato tranny into my HB lightning 10 specifically for the 2 speed. Are their any other problems with the Jato trans? I know I will need to have the mechanical brakes.

Jeff

no...

there is a alloy 2 speed gearset on ebay for ~$70

J57ltr
07.19.2009, 02:42 PM
Is that Jato trans that weak? My Rustler trans seems to take a ton of abuse without any problems (after you use a VXL diff and Steel idler), and I don't use a slipper at all.

Thanks

Jeff

whitrzac
07.20.2009, 01:48 PM
Is that Jato trans that weak? My Rustler trans seems to take a ton of abuse without any problems (after you use a VXL diff and Steel idler), and I don't use a slipper at all.

Thanks

Jeff
yes, but its a diffrent gear pitch and ratio than the rustler...

Unsullied_Spy
09.09.2009, 05:47 AM
Jato trannies are very weak. The Rustler tranny is tougher because it has steel gears (even though they are smaller pitch). I've seen people putting an 18T pinion in the tranny in place of the stock 17T and they said it meshed better and held up to a ton of power.

J57ltr
09.13.2009, 09:07 PM
I guess I'll look into this. I bought a JAto tranny a while back and thought about removing the center dif in my Lightning 10 and mounting the trans sideways. I want to keep the 2 speed but will have to use the mechanical brake and won't have reverse, but I want to set it up for top speed runs. I am not going to lock it into just second. Some people think that a 2 speed is useless for electric but I think it will keep the current draw down and allow me to keep the motor rpm's down.

What is the pitch on the Jato trans.

Jeff

whitrzac
09.13.2009, 09:17 PM
I guess I'll look into this. I bought a JAto tranny a while back and thought about removing the center dif in my Lightning 10 and mounting the trans sideways. I want to keep the 2 speed but will have to use the mechanical brake and won't have reverse, but I want to set it up for top speed runs. I am not going to lock it into just second. Some people think that a 2 speed is useless for electric but I think it will keep the current draw down and allow me to keep the motor rpm's down.

What is the pitch on the Jato trans.

Jeff


I thought that too, but the stock tranny WILL blow when it locks into 2nd...

J57ltr
09.13.2009, 09:32 PM
Care to splain? As I see it by the time the trans is going tro shift the power is going to be down as opposed to a nitro, so when second hits the motor will peak again, but then power will start dropping again as rpm's increase.

I do understand that the lower the overall ratio the weaker it is.

I don't know, I'm just asking.

Jeff

Unsullied_Spy
09.14.2009, 06:31 AM
I believe they are 32p gears.

A few reasons why 2 speeds don't work well with electrics:

1) BL motors work best with a certain amount of load on them, this varies between motors and setups but you ideally want to find the sweet spot and run it there. If your 1st gear is the gear where it is setup ideally and it only kicks into 2nd when you nearly max it out in 1st I suppose it would be good for a speed gear, but there are a few other issues.

2) A 2 speed will not reduce amp draw, it could actually make it worse. Amp draw of a BL motor is proportional to the load placed on it, when you shift into 2nd there is suddenly a lot more load on it and nothing to absorb the shock (part of reason #3) and the amp draw spikes because the RPM at the input shaft (being driven by your motor) suddenly drops but the ESC is still working the motor at the speed of 1st. The ESC can compensate for this quickly, but the increase in gearing will still require more amps to provide the power needed to get moving.

3) Drivetrain shock. Unless your slipper clutch is adjusted so loose that it slips quite a bit unless you're very gentle on the throttle as soon as it kicks into 2nd gear the sudden RPM change WILL tear things up. Think 2 speed clutches, one-way bearings, output yokes, U-Joints, stub axles, and tranny gears (possibly spur gear if your mesh is too loose).

4) When it shifts into second you will either spin the tires or wheelie, depending on how much traction you get (some nitros experience this same condition when shifting into second). Either way it is very possible you will lose control. This happens because when more load is placed on a BL motor the power output actually goes up unless you can't supply enough amps to feed the motor (in which case things start getting hot, fast). The sudden increase in power and RPM change causes your control problems.

That's about the best I can put into words, but I really think you're best off going with a properly setup single speed.

J57ltr
09.14.2009, 08:36 PM
1) If I'm trying to do 120 I don't want to run 12S and a really low KV motor. (I know it's less effecient) I'd rather stick with a higher Kv motor in the 3.5K range and more on the 4S-5S range (I use A123's) so that's why I think it would load the motor going into 2nd and allow me to run it up.

2) It's not going to be set for bashing at all just top speed runs. If I had a single speed the amp draw would be way up there when I start if it was locked in 2nd. The amp draw will be less than it would in a single speed and a little easier to get the speed I need without really overgearing it like I would have to do with a single speed.

3) Everything on the Lightning 10 buggy is metal, right now at the power levels I have on my Rustler (up to 1800W peak) the only thing I have trouble with is the stub axles (before I changed to VXL gears in the trans) and they are plastic and metal. Part of the problem is that I use a spool on it. I am not opposed to fixing the transmission it really isn't a big deal. Not to mention it's really lightweight I will be around 6 Lbs, maybe a little lighter.

4) It's a buggy so it sill still have a "center" Diff and I could change fluid to compensate for this couldn't I?


One of the things I don't understand is that if a Nitro engine which has a power curve inversley proportionly to a motor can do it why would a brushless be harder on it. I know the power will actually jump quite a bit with a motor, but I would think the Nitro would be just past it's peak when it shifts and right back into the sweet spot as it shifts. I guess these transmissions have a hard time in the stock application?

I guess you could say I am a hard head but I think I am going to try it anyway. Plus It's a little easier to make a motor plate to adapt a motor to the Jato trans. I would buy the RC monster Stadium 10 mount, but I will eather use the Jato trans or make my own mount.

whitrzac
09.14.2009, 11:07 PM
you want to do 120 with a jato tranny???:lol::rofl::rofl::rofl:

my setup was a novak HV 4.5(5000kv) on a 4s geared 18/56, I would get to 90% throttle and it would start slowing down. blew out the tranny...:diablo: even with the alloy gears, I still couldn't keep it together... mabey with a little more time, but its still a PIA

J57ltr
09.15.2009, 12:23 AM
What exactly blew out?

You know I totally forgot that I had an additional 3:1 reduction in the Diffs I have to deal with. I guess It may not be such a good idea after all. Even with a 1:1 ratio for the spur and pinion it's still too much.

Jeff

whitrzac
09.15.2009, 12:18 PM
What exactly blew out?

You know I totally forgot that I had an additional 3:1 reduction in the Diffs I have to deal with. I guess It may not be such a good idea after all. Even with a 1:1 ratio for the spur and pinion it's still too much.

Jeff

the top gear, then the middle gear...

J57ltr
09.15.2009, 01:52 PM
Seems like the same thing for the rustler. I chewed up the top gear on it as well a few times. Then again I don't run a slipper.

Jeff

reno911
11.30.2009, 09:08 PM
http://www.hot-racing.com/index.cgi?partnumber=SJT1000X&c=180

Build on my friends...

whitrzac
12.03.2009, 12:34 PM
http://www.hot-racing.com/index.cgi?partnumber=SJT1000X&c=180

Build on my friends...

$88:surprised:

mistercrash
05.22.2011, 03:37 PM
So how's the Jato tranny holding up? :lol:

whitrzac
06.07.2011, 03:59 PM
So how's the Jato tranny holding up? :lol:
IRRC I sold it in January 2010...

mistercrash
06.12.2011, 02:46 PM
Thanks for the update.