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-   -   Lets fix the Savage Transmission (https://www.rc-monster.com/forum/showthread.php?t=29260)

JasonB 02.05.2011 11:00 PM

Lets fix the Savage Transmission
 
1 Attachment(s)
The 29T and 32T gears (HPI 86084/86098) inside the tranny tend to granade or quickly wear eachother down to nothing depending on the batch; some are brittle and most are soft.

Both the 44T (HPI 100905) and the 18/23T (HPI 102514) are hardened and don't have this issue. Obviously HPI knows how to make a decent gear, but for some reason, they refuse to fix this problem.

First Attempt: I used GPM Delrin 32T (DSAV1232T) along with the HPI 29T because I figured metal on plastic works great with the pinion/spur, so why not in the tranny. I wanted to use a hard plastic gear, but I have been unable to locate one, so I figured I give delrin a go. My truck has never run so quiet, it was GREAT until . . . after about 10 min, the weak delrin gear broke; $11 down the drain. :cry: I really think a 32T gear made out of the same plastic that the 47T spur (HPI 76937) is made out of would be the ultimate fix for this transmission. It would be plenty strong, cheap, and very quiet.

Second Attempt: Some people have had success with the HPI Lightweight Drivegears (HPI 86274/86275). I'm currently running these and my experience is they are even weaker than the stock gears and wear down even quicker because they are so thin. I've got about 15 runs on them and they are already worn down to a point.

Third Attempt: Will be to go back to the stock gears, seal up the bottom half of the tranny with silicone or liquid gasket, and throw in a little synthetic, gear, or silicone oil (just enough to get the bottom of the lower gear wet).

Any other ideas; anyone fixed this thing yet?? :neutral:

Attachment 9685

lincpimp 02.06.2011 05:36 AM

Your third attempt idea should do the trick. The wear is caused by metal to metal contact. Oil will stop that. I have some of the stp oil additive that I have planned to run straight out of the bottle in my savage trans. Grease is just a waste of time, flings off at the rpms we turn stuff. Just wish the savvy diff cases were sealed.

JasonB 02.06.2011 10:56 AM

Something I noticed in my Honda 1/1 when changing out the transmission fluid was a magnet at the bottom of the pan. Seems like a good idea in this application because those gears really like to eat each other up and the magnet would help prevent those shavings from getting continuously cycled through all the gears with the oil splash.

lincpimp 02.06.2011 04:48 PM

Quote:

Originally Posted by JasonB (Post 396840)
Something I noticed in my Honda 1/1 when changing out the transmission fluid was a magnet at the bottom of the pan. Seems like a good idea in this application because those gears really like to eat each other up and the magnet would help prevent those shavings from getting continuously cycled through all the gears with the oil splash.

Good idea, A small high powered magnet glued into the case somewhere would be great. I have seen those magnets somewhere, I will have to look again.

Jahay 02.07.2011 07:29 AM

15 runs is great out of any savage internal gears to me!!!

i was getting max 5-8 runs out of the light weight gears... which is the same out of the stock cast gears... so i just carried on using stock..

I like the sealed box idea, but i found the best solution which is a centre diff conversion!!! ONLY WAY TO CURE THIS WEAK TRANNY PROBLEM! get rid of it!

mjosparky 02.07.2011 03:45 PM

Quote:

Originally Posted by lincpimp (Post 396881)
Good idea, A small high powered magnet glued into the case somewhere would be great. I have seen those magnets somewhere, I will have to look again.

See if you can find a small “rare earth magnet”. They are strong and hold their power almost forever. :yes:

Sparky

JasonB 02.08.2011 05:38 PM

Quote:

Originally Posted by Jahay (Post 396987)
I like the sealed box idea, but i found the best solution which is a centre diff conversion!!! ONLY WAY TO CURE THIS WEAK TRANNY PROBLEM! get rid of it!

I have considered the center diff, but I haven't seen a straight forward way to get it done. Everyone that's done it has had to custom fab a mount. I've been holding out for some company to come out with a drop in solution for the Savage. If the tranny becomes a real pain, I will pursue the center diff for sure.

Other thing is custom length bones; sounds pricey.

Jahay 02.08.2011 05:43 PM

it sounds pricey.. but imagine the price of a drop in centre diff conversion that will cure all the savage tranny problems? THAT WILL COST A LOT because everyone wants it...

All you need is a centre diff, diff mounts, custom alloy diff plate and maybe one custom dog bone which i paid $20 for... so its not as tough as you may think

ZippyBasher 02.08.2011 06:05 PM

With all the Cars and Dog bones made for them. I doubt you need any "Custom" shafts. Just takes a little time and effort to find what will work for you. I mean they make 50-145mm dogbones. Gotta be something you could use...

I agree though CD all the way. It actually makes MT handle somewhat decent... :lol:

josh9mille 02.08.2011 07:17 PM

Maybe we should get Monster Mike to make some hardened gears for the tranny that are full width instead of the narrow ones from HPI

What's_nitro? 02.08.2011 08:48 PM

Quote:

Originally Posted by josh9mille (Post 397172)
Maybe we should get Monster Mike to make some hardened gears for the tranny that are full width instead of the narrow ones from HPI

$$$$$ :lol:

Could be worth it if the demand is high enough. There are lots of Savage owners out there...

josh9mille 02.08.2011 10:28 PM

Quote:

Originally Posted by What's_nitro? (Post 397186)
$$$$$ :lol:

Could be worth it if the demand is high enough. There are lots of Savage owners out there...

It would be better than trying to modify everything to run a CD. Luckily I have had no problems with my HD gears so im not really worried about it.

JasonB 02.08.2011 11:47 PM

3 Attachment(s)
I think all we need is a hard plastic 32T gear to run with the stock 29T and it would last for a LONG time and be cheap and easy to replace because it's the top gear. My $3.50 47T plastic spur has lasted for 6 months and is showing no signs of giving in.

Pics of my new tranny. Three magnets that I had in my parts bin. One is under the gear wedged beneath the bearing holder. Just have to wait for the top gear to come in.
Attachment 9701Attachment 9702Attachment 9703

JasonB 02.09.2011 12:12 AM

Quote:

Originally Posted by ZippyBasher (Post 397167)
With all the Cars and Dog bones made for them. I doubt you need any "Custom" shafts. Just takes a little time and effort to find what will work for you. I mean they make 50-145mm dogbones. Gotta be something you could use...

I agree though CD all the way. It actually makes MT handle somewhat decent... :lol:

You would think that with all the Savage owners out there someone would have found the part numbers of the existing bones needed to make this happen already and it would be common knowledge. :neutral:

I'll be first in line for a relatively straight forward approach to a Savage CD.

thzero 02.09.2011 12:25 AM

Probably because each CD conversion seems to be different.

Quote:

Originally Posted by JasonB (Post 397208)
You would think that with all the Savage owners out there someone would have found the part numbers of the existing bones needed to make this happen already and it would be common knowledge. :neutral:



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