I've just re-built my first diff...

[Doyley]

Should it sound like a metallic cat purring when I spin one end of it?:lmao3:

It appears to be a lot tighter, but it makes a sort of a noise (See description above)....

Also, just noticed I have 3 teeth missing from the small cog thing that drives the rear diff (Excuse the lack of technical terminology... I'm still learning how to drive the bloody thing, let alone fix it). I have a spare one, but I'm unsure how to get to the small allen key to remove it. Any pointers greatly appreciated!

Oh yeah, Happy New Year!

Thank you

Mark

 

[Mickey]

the sound you describe sounds correct when they are together. you can access the allan key through a small hole in the skid plate. then the spur should come out . also you should check the 43 tooth pinion gear for wear

 

[Doyley]

Sorry Mickey, either our lines are crossed, or I'm being thick. Plus, it appears I made some of the last post up....

The spare thing I have has an allen screw on it to attach it to a shaft. The cog thing on my truck doesn't. It's a Savage X 4.6 RTR in case that make any DIFFerence....:duh:

Thanks mate

Mark

 

[Mickey]

got any pics? i was thinking you were talking about the gear that stays in the bulkhead when you remove the diff.

 

[Jon]

u talking about the bevel gear?

 

[Doyley]

Sorry Mickey, no pics. If this is still going on tomorrow, I'll grab the camera off of the wife and get some.

When you remove the rear diff, there is a cog that stays to the rear of the diff compartment. It does look like it pokes out of a bulkhead...

The spare cog with allen screw I have is straight sided, the cog to the rear of the diff compartment is bevelled (angled?). It looks like a replica of one of the smaller cogs in the diff casing.

Hmmm.. a picture says a thousand words....

lol

Mark

 

[Doyley]

86031 is the kiddy.... http://www.benracing.co.uk/acatalog/HPI_Savage_X_Suspension_Exploded_Diag.html

That makes far more sense now....

So I'm guessing there's a small hole where I can access the allen screw, eh Mickey?!?!?!:duh:

Thank you for your patients gents.. I just want to get this back on the road before I have to go back to work....

 

[Mickey]

if you are careful enough the driveshaft and cup will stay put . just stand the truck on end

 

[AllanQ]

that part is commonly refered to as a pinion gear. If it has 3 teeth missing from it, it needs to be replaced. You have to take off the skid plate assy to get to the drive cup. you will see a hex screw in the drive cup, remove that screw and the drive cup will come off and you can remove the pinion through the other side of the bulkhead. When you put it back together make sure you use some threadlock because the grub screws like to come out. Check the ring gearalso, the gear on the diff itself, and see if the bad pinion has caused any damage to it. there are several reasons why the pinion will break (landing jumps on the gas etc) but there is a way to minimize pinions breaking and wrecking ring gears.

Here is the link on how to shim the diffs...
https://www.hpisavageforum.com/forums/showthread.php?p=17401#post17401

basically you will put about 2 shims betwen the bearing and the ring gear. Hope this helps you out.

 

[Doyley]

Well it's done!

Thanks for all your help gents, I'd have been knackered without it.

I re-built the diff, changed the bearings, shimmed it, changed the ring gear, changed the pinion gear and now the beast is on charge. As well as the pinion gear missing 3 or 4 teeth, the grub screw on the drive cup had also gone missing.
I also managed to pour fuel all over the varnished wooden kitchen table and I now have some explaining to do to the wife, as it's gone a bit strange.... I don't suppose any of you are French Polishers??? :duh: lol

Now I've tackled my first maintenance extravaganza I can feel a total re-build coming on in the summer....

Game on!

 

[kgrames]

What does everyone use to clean out the grease in the diffs when installing oil? I want to try and keep all the bevel gears in place while getting the grease out.

 

[Mickey]

brake cleaner will work with good results

 

[frddyj]

What does everyone use to clean out the grease in the diffs when installing oil? I want to try and keep all the bevel gears in place while getting the grease out.

your better off removing the gears & cleaning the grease off each individual pc & cleaning out the diff case. its easier that way & a breeze to re-assemble😛eace:

 

[Doyley]

Listen to Frddyj, mate. Speaking as someone that was a diff assembly virgin, it really is quite simple and you guarantee it all gets cleaned properly.
Now I've done one, I reckon, with all new parts at the ready, I could strip and re-assemble in under an half an hour. I'm sure some of the experienced lads on this forum could probably do it a lot quicker.

Go for it! Every day's a school day.....