SMOKER1

Check grub screw holding drive shaft in place on the gearbox. Happens to me regularly where the screw comes loose. I made the mistake of taking my diffs apart for a quick 2 minute fix.

HerrSavage

Thanks - which gears are those? Are they the ones inside the diff?

-SomeGuy-

No, outside.

HerrSavage

That's what I thought.. Seen those though - they look fine..

-SomeGuy-

Well i cant think of any other reason why your loosing power in the back only.

HerrSavage

Me either.. Lemme try to explain the prob again..

When giving gas - even 1/2 throttle, the engine winds really high(and loud...) With the Mulcher tires on, grass immediately shoots up everywhere.. From watching it move, it seems %70 of the power is going to the front wheels. At WOT it's screaming really high, but not moving nearly as fast as it should, as if something is being skipped or not catching. There's also a metallic rattly/crunchy sound.. When I hold it up in the air while running, all four wheels move like normal. Not running, all the wheels rotate as they should, including the two front wheels down rotate the rear two test, etc..., indicating that the diffs should be fine..

I threadlocked that grubscrew in - the only weird thing I noticed on initial inspection.. I also took the top of the tranny off and all the gears - that I could see - there looked normal...

I've got another long work-day ahead of me, but hopefully I won't be so exhausted and brain-dead later so I can go over it all again...

Not being able to get those rear two screws out is making life difficult.. I also rounded out my fourth or fifth t-wrench, so I can't even get the rear left wheel off....

mazdab2600

herr
i've had the same problem the gears looked good its the bearing is toast on the gear side allowing the diff to slide away from the pinion.
http://www.savage-central.com/module...+diff+bearings

HerrSavage

Thanks both of you guys for your patience... I'm just so slammed busy with work this week I don't have the leisure or time to sit in there and wrench around and take everything completely apart..

Mazda, so the symptoms sound the same?? So to get at the bearing you mean, I just have to take out those six screws, the upper hinge pins, and take the diff out? If so that doesn't sound too bad...

As for my driving-style, I learned my diff lessons with my first Savage 25(RIP), so I try to never land on-gas, no donuts, etc.. But I AM a WOT junkie, and I have to admit, I've probably got more mileage wheelying with the Savage in the last gallon or so than on all fours.... And I have kind of wondered what that was doing the rear diff...

Axial RR testing from last weekend..:

http://s166.photobucket.com/albums/u...avyAxialRR.flv

Couple weeks before, with Spec 1S:

http://s166.photobucket.com/albums/u...inandWh.07.flv



I'll rip that diff out later..

Thanks again guys....

-SomeGuy-

If it is the bearing that could explain it, im still on the original bearings that came with the truck so i've never had that problem. Any slipping in there will make the gears wear down though. Did you take a look at the sg? If your getting lots of revs but no much motion maybe the slipper is getting old but i doubt its that.

mazdab2600

when i was burning up bearings.
i bought all these spare's.knock on wood haven't used them yet.
must have just been a batch of bad bearings.

HerrSavage

OK, this is what I found.. One filthy diff, with one very blown looking bearing on the side...

Now, whuddaya' reckon would be the best way to go?? Just get a new bearing, and whack it all back in there? I also have a backup brand-new Savage SS(old style) complete diff I bought a long time ago as a backup).. I could a.) just take a bearing off it, put everything back together, and go for it..., or b.) switch out the whole diff, into the alu cup - though this would require shimming and I don't want to do that.. Another option would be to throw the whole new diff in a new Kyosho cup I also bought a while back..

Is it bad if when I put everything back together there's gunk all up in everything??

And lastly, is this one bearing likely to be the only thing causing my problem, or could there be something else?.. Before I go putting everything back together......

HerrSavage

Just looked at your pic again Mazda( though I can't open up these damn new pics on RCU...), and sure enough - exactly the same problem like you said...

So if I just replace that bearing I should be all good then I guess....

ps Is that the only bearing you've had problems with, or are there more?

HerrSavage

Now, having switched out the bearing, when I screw the four screws in down tight, the diff feels all bindy and too tight.. What's up with that?..

azzman

Firstly to answer someones earlier question about Patricks post count, this thread should give you an idea as to why that is...instead of just getting on in there and trying to sort the problem for himself, he has to have everyone else diagnose the problem (then if he had his way, probably fix it too!!!) before thinking about it, then asking a bunch more questions, thinking about it some more, then blah blah bloomin blah!

I CANNOT BELIEVE that someone with an (easy access) X diff didnt have have that puppy out and the problem sorted ages ago! You spend more time on here asking, moaning (remember the "the X is so crappy" thread!) etc than actually just sorting it out.

And as for not having tools, for someone that can afford/has a few RC's and new motors etc, there is NO EXCUSE for having crappy tools, you are just asking for trouble! And IMO every you should have a decent set of Hex head screws, you get way less stripping (if you get decent quality).

And dont be afraid to shim diffs man, this is bread and butter to a half decent RCer...

No offence Pat...you just need to stop being a Nanna!

mazdab2600

pm'd ya

HerrSavage

azzman, I think you need to just p.iss off. I couldn't care less about post counts.. I've probably got hundreds saying things like "nice ride!.." or whatever too..

People like you however add to your post count by posting pointless trash-talking junk like your post here. And that's all you're doing - talking trash..

I've screwed in and unscrewed those four screws on the diffs like 20 times trying to get them right, and half going off a Savage 25 manual, and thanks to mazda just giving me the alloy diff instructions, I should be able to sort it out now..

According to your stupid reasoning, nobody should post anything and just wrench and wrench and wrench and hope it eventually works out. This is a forum after all, so I don't think a little discussion is such a bad thing. Maybe there are others with the same problem but who are too inhibited to ask, cuz they may have to deal with stupid waste-of time posts such as yours.. If however you are too thick to participate or contribute anything constructive, then turn off your computer and go outside and return to playing with sticks and rocks or whatever..

So again, I'll just stop here and leave it up to your imagination what you can go do to yourself "mate"...

azzman

Well here you basically say that you will have to take the whole truck apart, when you suspect its a diff problem...then it takes 16 posts and 3 days before you actually sum up enough courage to take the suspected diff out...and bingo 15 minutes later you have the problem solved...
I REST MY CASE NANNA....no trash talked just facts. Sorry if the truth hurts...

HerrSavage

The problem is not solved.. In fact, I have to go to work soon, so it may take a whole'nother day.. As for taking the whole truck apart, so far I've taken about half of it apart.. At first I thought it was the tranny, so I took the top off it, roll-bar, etc.. Then I tried to get the TVP's off, then the wheels, one of which still won't budge...

So in any case, if anybody else comes along and reads about the symptoms I had, he'll be able to avoid some of this and cut right to the diff bearing... Even if it's only one dude, that would be something constructive..

So, just to clarify that in the face of yet another senseless flamer-post...

Thanks a lot mazda2600 for the diff-manual, and Someguy for your help too.

I'll give it another go when I get a chance...

HerrSavage

OK, no longer a diff virgin... Just tested, running great... Chalk up another correct diagnosis to mazdab2600..... Thanks again.. I guess all that wheelying was taking its toll on that bearing..


Also wanted to clean off my Mulchers from running on the track last week by running in some wet grass(been raining and crappy here for days...) Just wanted to say - Mulchers are some freakin' nice tires.. If you run on a track or in wet grass, I can't imagine a better combo than Maxx-size Mulchers on these Ofna full offset dish rims... Shooting grass up like a lawn-mower... Never did clean the inside out around the diff - but ouside it's lookin' pretty spiff now from the run in the grass... Might go clean the Mug off the same way..

Vigilante212

You should have cleaned the inside of the diff casing. The dirt acts like an abrasive wearing the teeth out. I also blew a diff bearing a few weeks ago same side this was after I shimmed it. When I reasembled the diff with new pinion and new planetary my diff was too tight so I ended up removing one shim now its smooth as butter. I also tore the entire diff apart and removed both bearing from it since one failed it strained the other so I took no chances of that failing also. I also relubed my diff(trying 10k weight in the rear instead of 30k for a bit) and regreased the planetary. Now I just need to get it on the track maybe today, but I doubt it most likly tommorow before I race.

F1aw1ess

Just wanted to say im a complete newbie to all this rc stuff but have a similar issue to yours, i also wouldnt want to just strip everything down in fear of breaking more than i fixed so i appreciate you asking all those questions as I know where to start looking now, Azzman is certainly fitting of his name 'Ass'