Tight diffs (problem when going around)
 

Hey guys,

I've just fitted new housings and gears in my truggy. (replaced oil too) On both the front and middle diff so far. Greased up the front diff lots around the housing and gears (outside). No dirt inside or around there. It does it when not fitted to the truggy the same.

For some reason the front when rotating seems to have a point where it gets pretty hard to turn, at first I thought it was the set-screw in the housing rubbing against the gear, but I filed it down so it was flush and it's still the same. (It's not actually at that point, but close).


I can't see any obvious causes, I spent all day and re-done it 3 times but it's still there on the front and in the middle diff slightly but not as strong.

Any ideas? Please help me :).

RE: Tight diffs (problem when going around)
 

Some diff gears need to be broke-in before they rotate smoothly .

RE: Tight diffs (problem when going around)
 

I had that issue when I redone the diffs in my Savage, turns out i over tightned the srews in the diff casing. after I loosened them off and thread locked it , it spun freely.

RE: Tight diffs (problem when going around)
 

Ah, could be I done them as tight as I could (hand tightness) but today I done this on the rear diff and it's as smooth as silk :/. I'll re-do the front without doing them up so tight, see if that helps.

Dawman, I don't think it's the internal gears (inside housing) as it doesn't matter when I hold the outside still and rotate both axles (very smooth). The outside gears are the same as what was in there before, just cleaned and greased up again.

RE: Tight diffs (problem when going around)
 

Oh , some reason I thought you put new gears in . But if you tightened the screws more then snug then probably it .

RE: Tight diffs (problem when going around)
 

I did put new internal gears in (not external). Seems strange that it's worked fine on the rear ones.

Also the centre diff and rear today is smooth all throughout, just the front one.

Thanks everyone :).

RE: Tight diffs (problem when going around)
 

Ya, that had me stumped for a while. Id close it up and it would bind, take it apart and everything moved fine..........

RE: Tight diffs (problem when going around)
 

You're on about the outside gears right (not the 6 inside ones)?

:)

RE: Tight diffs (problem when going around)
 

For your new bearings, did you get bearing oil? I highly suggest whenever anyone replaces their bearing, or even in a brand new RC, to get bearing oil and lube up te bearins. Dont trust the factory to have lubed them for you.

As for the stiffness in the front rotating, I am stumped here. Aside form setscures and all, have you also inspected teh CVs/drivecups & dog bones? If those are bent, they can make for very rough turning and wobbling. Also, look at the chassis: is the front half of teh RC bent or out of shape in any way? A bent chassis can cause problems by making the CVs/shafts/dogbones&cups go out of alignment, thus also making for hard rotainint of the drivetrain.

RE: Tight diffs (problem when going around)
 

I haven't replaced the bearings, diff housing ones smooth by hand, even under pressure. The two in the diff case on the other hand are slightly notchy, so I've got 10 rubber sealed bearings on the way to replace them. I still don't think this would cause the real tough amount of friction in one spot as they rotate pretty smooth still (even under load, just I can feel bumps so no good).

Normally the factories lube them with grease, specially sealed ones? I'll check them anyway, do the rubber seals pull off without damage?

I have some diff cases on the way too, just in case the front one is a bit tweaked. It does the same when out of the truggy, just moving by hand while holding both case halves together even.

I also brought some shims so I can shim it for hardly any backlash.

RE: Tight diffs (problem when going around)
 

Hey guys, fixed it by installing a new diff case half, using two new shims and installing two new bearings. Smooth as silk now! All three done :).

Just doing the rest of the car, looks so nice and clean, cleaned every part. 100% perfect other than the front bumper being broken :D.[:@]

RE: Tight diffs (problem when going around)
 

Well, the Truggy runs amazing! So smooth and quiet now... The diffs must have been worn out a lot before! Not one problem, just fun :D.

It's just too awesome to watch the water get kicked up into the air by the tires!

Man, caked in wet grass and mud, lol! Cleaned it all off. Next purchase is going to be a decent air compressor. (also for air brush)