Are these parts damaged ? (Gearbox parts I think it’s called)

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
Hi decided to do abit more stripping and cleaning and also to see why the truck would not push forward with ease.

Please forgive me if I’m calling the parts the wrong name!
1 of the gear box when spinning the arm (that holds the dog bones) spins really well- I get w couple of full spins, where as the other when I spin it , it gives me 1 full spin then stops.
Opened both gear box housing and found 1 cogs teeth not sharp at all compared to the other.
The bearing one of them is not flat against the surface and also the big cogs gearbox the teeth’s are not sharp not sure if this is meant to be like this.

Do I need new parts?

Please see pictures , pictures are not great but hopefully you can help from it
F78D083C-294B-49C6-81DB-356EDF98A737.jpeg2AEDDFAF-AF0A-4E85-8F4A-44C17EEBC21C.jpeg66B4C2B6-3327-4A6C-A952-E05E71266E28.jpeg4FE26A02-E20C-4183-B80A-5F50E07F2AC2.jpegE4E35FBC-4094-4878-BE0E-AC3FD8AE17EF.jpeg762D919C-4C8F-4F41-8595-8913D3544171.jpegBF9547F4-52DE-4DCC-B482-C1A16C50A3C9.jpeg
 

Jam Racing 1

Well-Known Member
HPISF Supporter
Messages
4,716
Yes you would remove the ring gear to access the internals......
They may be locktited in but you can get them out if you heat them with the tip of a hot soldering iron and use the correct fitting tool to remove them.....

as for the term "bulletproof" you know as well as I do that there are NO INDESTRUCTIBLE parts even though they put that label on them... :rolleyes::rolleyes::rolleyes::rolleyes:
 

Sparky

Active Member
Messages
91
hi

i thought the parts on the savage xl are bullet proof - comes as standard ??
The earlier models of the savage XL had hardened ring and pinion gears,
but these were prone to breaking so Hpi changed to the 29/9t bulletproof gears
It was the later model XL
 

Biddie_fiddler

Well-Known Member
HPISF Supporter
Messages
158
Location
Perth, WA
Bulletproof is just marketing terms! Trust me they're not actually bulletproof - but they are stronger (imho) than the ones you currently have
 

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
Yes you would remove the ring gear to access the internals......
They may be locktited in but you can get them out if you heat them with the tip of a hot soldering iron and use the correct fitting tool to remove them.....

as for the term "bulletproof" you know as well as I do that there are NO INDESTRUCTIBLE parts even though they put that label on them... :rolleyes::rolleyes::rolleyes::rolleyes:
Jam - i will try that tonight, in removing the screws - if i manage to open it - what am i looking for ? teeth to be sharp or will they be blunt ? obviously if the teeth are bent or broken it means needs replacing.

as for bulletproof = yes i know, someone mentioned to get bulletproof so i was referring to as i thought the standard parts on savage xl are.
 

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
Yes you would remove the ring gear to access the internals......
They may be locktited in but you can get them out if you heat them with the tip of a hot soldering iron and use the correct fitting tool to remove them.....

as for the term "bulletproof" you know as well as I do that there are NO INDESTRUCTIBLE parts even though they put that label on them... :rolleyes::rolleyes::rolleyes::rolleyes:
Managed to get 2 screws out and the 2 remaining
😡😡😡
Tried every thing even tried drilling the b******
No joy

Must be easier just to buy new ones 😡
The ring gear of the one I have taken picture of the teeth are defo blunt compared to the other one
 

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Sparky

Active Member
Messages
91
What I done with mine was stuck it in the oven for 5 mins at 180 degrees,

It'll break free the thread lock just make sure you wear heat resistant gloves,

That screw you've started to drill out is almost there,
Just drill a little more to remove the head of the screw,
once you heat the unit in the oven And take the rest of the screws out the ones with the drilled heads can be removed with pliers after you get the ring gear off the diff.
 

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
What I done with mine was stuck it in the oven for 5 mins at 180 degrees,

It'll break free the thread lock just make sure you wear heat resistant gloves,

That screw you've started to drill out is almost there,
Just drill a little more to remove the head of the screw,
once you heat the unit in the oven And take the rest of the screws out the ones with the drilled heads can be removed with pliers after you get the ring gear off the diff.
I’m just tempted to buy new ones
But assembled ones are like £50 each 😳
Almost had a heart attack 😱
Is it a lot of hassle if I was to buy all the bits separately and then trying to put it all together ?

To be honest I’m not even sure if the inside gubbings are ok or damaged!

Are they suppose to be kind of tight when twisting the arms?
And are you suppose to feel almost a click type when twisting it slowly ?

Ow I seen some differentials on eBay for £18 they are not HPI brand but wasn’t sure if they are actually any good ?
 

Jam Racing 1

Well-Known Member
HPISF Supporter
Messages
4,716
I’m just tempted to buy new ones
But assembled ones are like £50 each 😳
Almost had a heart attack 😱
Is it a lot of hassle if I was to buy all the bits separately and then trying to put it all together ?

To be honest I’m not even sure if the inside gubbings are ok or damaged!

Are they suppose to be kind of tight when twisting the arms?
And are you suppose to feel almost a click type when twisting it slowly ?

Ow I seen some differentials on eBay for £18 they are not HPI brand but wasn’t sure if they are actually any good ?

Do yourself a favor and stick with genuine HPI parts, you do not seem like you would be able to retrofit and massage something to get it to fit and work properly, the only way to know for sure what is inside is opening the diff and checking what is inside and if they are still usable...

as for feeling a click when rotating, no the differential action should be smooth and easy to turn with minimal resistance felt....
and yes you can buy all the parts individually but to be honest getting them assembled is easier if you are unfamiliar with sourcing the parts, either way if you buy the diffs assembled you should still take the ring gear off and pack with grease or fill with oil to get the most out of your purchase......
 

OnThatPipe

On a vacation
Messages
63
The pinion is the only thing that looks fried. I would try ti figure out what caused that. Was everything stock or did you rebuild the diffs prior? I would check:
-- Diff housing to see if there is play in the pinion insert causing it to wobble
-- How are the bearing inserts in the housing?
-- Did pinion set screw come loose from drive cup? (especially if it stumbles)
-- Is there a shimming issue somewhere in the diff housing?
--Is the crown gear secure and flush?
--Grab both out-drives and see if you can wobble it while in the housing.
--Is the diff still smooth or did the crown/sun gears lose their mesh?

Obviously, something moved, so try to find out what moved. I'd hate to see that happen again as it shouldn't. Let us know what you find.
 

olds97_lss

Well-Known Member
Messages
2,067
Location
Dekalb, IL 60115
as for the term "bulletproof" you know as well as I do that there are NO INDESTRUCTIBLE parts even though they put that label on them... :rolleyes::rolleyes::rolleyes::rolleyes:
Nope, not bulletproof:


Well... maybe bullet proof, but not idiot proof. ;) I have 2 or 3 pinions that look like that. From my Flux HP though before I put a center diff in it. I'm running the sintered BP ring gears in both my flux hp and X. The BP pinions are all the same machined steel. There are 2 kinds of the BP ring gears though, sintered and machined. Machined being better, but more expensive.

As for why your pinion burned the teeth off, you really have to shim the diffs, even when using plastic cases. It helps prolong the gears lives. Your going to want to closely inspect the ring gear as well on that ran against the damaged pinion. It may have some teeth ground down which will cause a new pinion to die faster. Also, HPI used a stupid sized bearing on the alloy cup side of the diff that tends to fail fairly fast. If you bash a lot, you may get a season out of it if your lucky. The one in my nitro savage holds up longer than the ones in my flux. Less torque beating on them. Once that bearing goes, it takes a pinion with it usually. The one on the cup side is 10x16 vs the 8x16 on the gear side. It's best to replace both whenever you have the diff that far apart. Can get them for $1 a piece at fasteddybearings.com if your in the US. I run his bearings in all my stuff and they hold up well.
 

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
What I done with mine was stuck it in the oven for 5 mins at 180 degrees,

It'll break free the thread lock just make sure you wear heat resistant gloves,

That screw you've started to drill out is almost there,
Just drill a little more to remove the head of the screw,
once you heat the unit in the oven And take the rest of the screws out the ones with the drilled heads can be removed with pliers after you get the ring gear off the diff.
Didn’t do what you said, I took it into work and got 1 of the engineers to open it up with his special tools took him less than 5 mins lol
 

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
Do yourself a favor and stick with genuine HPI parts, you do not seem like you would be able to retrofit and massage something to get it to fit and work properly, the only way to know for sure what is inside is opening the diff and checking what is inside and if they are still usable...

as for feeling a click when rotating, no the differential action should be smooth and easy to turn with minimal resistance felt....
and yes you can buy all the parts individually but to be honest getting them assembled is easier if you are unfamiliar with sourcing the parts, either way if you buy the diffs assembled you should still take the ring gear off and pack with grease or fill with oil to get the most out of your purchase......
Took it into work and got one of the engineers to open it up for me 🙂

All inside cogs seem to be fine, no broken / damaged teeth, they are not sharp but I’m not sure if they are suppose to ?

They do turn smoothly I don’t feel any resistance at all
Although when I try to move the arm /the bit where the dog bones connect to they tend to move 1-2mm if I try to push in and out and also up and down
Is it meant to have a tiny giveaway and able to move ? Or is it mean to be solid and not even a 1mm movement either way ?

Inside gubbings looks simple nothing complicated about it.
 

Atarioldskool

Active Member
Messages
122
Location
Leicester UK
The pinion is the only thing that looks fried. I would try ti figure out what caused that. Was everything stock or did you rebuild the diffs prior? I would check:
-- Diff housing to see if there is play in the pinion insert causing it to wobble
-- How are the bearing inserts in the housing?
-- Did pinion set screw come loose from drive cup? (especially if it stumbles)
-- Is there a shimming issue somewhere in the diff housing?
--Is the crown gear secure and flush?
--Grab both out-drives and see if you can wobble it while in the housing.
--Is the diff still smooth or did the crown/sun gears lose their mesh?

Obviously, something moved, so try to find out what moved. I'd hate to see that happen again as it shouldn't. Let us know what you find.
Opens it up but all cogs look perfectly fine.

As for rebuild the diff etc- I purchased the truck from someone, he has done a lot of aluminium mods done to it but I am change certain parts to plastic .

I can’t seem to see why the teeth are blunt
Everything seems ok inside it
 

olds97_lss

Well-Known Member
Messages
2,067
Location
Dekalb, IL 60115
The ones inside are probably fine. Once you put the ring gear on there with the sun gear, it holds everything in place. The only real "shimming" you usually need to do on a savage is for the ring/pinion by adding shims on the ring side, which you can only do with the diff apart, so it's a bit tedious. You have to put the ring gear on without the output shafts, screw at least 2 screws opposing corners, put it in, check mesh. Add shims under the ring bearing, put it in, check mesh... once you get it so there's very little play, you then fill the diff with oil (I use 50K, could go higher), put the shims under the bearing, put the shaft back in the ring gear/washer covering the o-ring, pin on the shaft, sun gear on, tighten it down with threadlock on the screws and install.
 
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