Help a Noob with a diff problem

[daz75]

Stupidly bought a second hand car with another "near complete" one that ic ould build for my other lad (the joys of twins) I'm nearly there but i noticed the wheel weren't turning properly, so i decided to remove the diff to see if there was an issue.

I think the problem maybe the diff wasn't tight. So i'm trying to screw the diff screw into through the outdrives and into the nut in the nut holder on the other side, but it simply wont tighten. I've removed the nut and screw and done it without the outdirves and it tightens fine, the screw is the correct length but i just can't get it to work, any ideas much appreciated.

its a losi 22 by the way

[NeilRalph77]

I take it the diff is complete? No parts missing?

Search TLR diff build on YouTube there's a full guide.

[daz75]

Originally Posted by NeilRalph77

I take it the diff is complete? No parts missing?

Search TLR diff build on YouTube there's a full guide.

yeah gone through all the youtube stuff, all seems to be present and correct

[NeilRalph77]

It's difficult to say without having it to hand, my initial guess would be that the nut is stripped, it could appear fine unassembled and finger tight but under load be skipping the threads.

[daz75]

took a closer look at the 6 diff balls on the screw and there was an extra washer one side (so 3 instead of 2) removed that and the screw reached took far too long though :-(

[daz75]

finally got some electrics and when i run it off the ground the wheels turn but on the ground it doesn't move

i've tightened the slipper tight ive took the diff back out to check it, i turn the screw and it doesnt seem to get any tighter than it already is, any ideas please as im loosing the will to live

[cutting42]

Something is not connected properly then.

1/ Car switched off, on the ground try turning the spur by hand. Does it move the car? If you hold the car back resisting the drive is something slipping?

2/ If it is slipping somewhere try turning the layshaft with a nut driver on the slipper nut to rule out the slipper and see if you get drive.

3/ If no to the above, check the gearbox gears are not stripped

4/ If OK check the wheels are on correctly with the drive pins in place and the hexes are not stripped

5/ If all the above checks out it is definitely the diff. You should be able to tighten it so you can't tighten it anymore, if you can't then the nut maybe stripped of the internals are not correctly built.

6/ It sounds like you have a second car. Try swapping the working diff into this car to confirm the rest works.

7/ Compare the two diffs but I can understand you not wanting to strip the working one down.

Take lots of pictures and post them on here.

[daz75]

Thanks cutting I've tried step 1 before work and the spur just spins and doesn't move the car I'll try the other checks later

Guess this is a leason for me not to buy stuff where they say there is enough spare parts to build another car out of

[daz75]

Originally Posted by cutting42

Something is not connected properly then.

1/ Car switched off, on the ground try turning the spur by hand. Does it move the car? If you hold the car back resisting the drive is something slipping?

as mentioned above, no it doesn't

2/ If it is slipping somewhere try turning the layshaft with a nut driver on the slipper nut to rule out the slipper and see if you get drive.

Turns ok, cant see an issue there

3/ If no to the above, check the gearbox gears are not stripped

Gears look fine to me, see pics

4/ If OK check the wheels are on correctly with the drive pins in place and the hexes are not stripped

Checked drive pins and hexes, look fine to me, see pics

5/ If all the above checks out it is definitely the diff. You should be able to tighten it so you can't tighten it anymore, if you can't then the nut maybe stripped of the internals are not correctly built.

Read the big thread on here about the diff, it mentions using the B4 diff screw instead as apparently that's better, is that the best thing to try? I assume its this one
http://www.ebay.co.uk/itm/2721446223...%3AMEBIDX%3AIT

6/ It sounds like you have a second car. Try swapping the working diff into this car to confirm the rest works.

7/ Compare the two diffs but I can understand you not wanting to strip the working one down.

Take lots of pictures and post them on here.

Not had chance to swap stuff about with the other car, pics below

[daz75]

If someone could confirm the eBay item question??

[diago999]

Daz, Im afraid I cant help with your eBay question but there is a right and wrong way to build the diff (I've done it before!) page 28 of the manual shows the spring and t nut going on the outdrive that has the center bearing support, if you've got the sides wrong then the bolt wont engage the nut at all.
Secondly it looks like you've already got the losi aluminum nut holder, which would mean you shouldnt need to get the b4 one, just swap the nut out, (make sure its the right thread for the bolt though!)

Hope this helps.
Tristan

[danielc3009]

Looking at the fourth picture I think you've built the diff wrong. The diff bolt looks to far out of the diff out drive, I can't remember the bolt being that far out on my 22. It looks like you've put the little plastic dust cover on the bolt but it should go in the diff out drive once the diff is fully assembled and tightened. I've attached a picture from the manual with the part circled.

[daz75]

i really can't tell what you mean, here's a picture of the diff un-assembled in the order i think it goes together, the part you've circled is just a cover for the bolt isn't it?



I've also watched this a number of times and can't see what i've done wrong

https://www.youtube.com/watch?v=EToj2yX76NU

[NeilRalph77]

Right you need to do some measuring or some rebuilding with parts missing to see where the offending item is.

First off without the spring does the T-nut slide all the way down the outdrive?

Rebuild the diff without the main gear and diff balls,

Does it pull up tight?

Try pushing a loose diff ball between the diff rings 2 @ 180* better 4 @ 90* better still,

If the gaps too small then the outdrives are pulling together close enough and there's something happening when you tension the screw.

If the balls push in then the gaps to large, are the diff balls the right dia? are the bearings too wide? have the diff plates been sanded to far making them too thin? is the stub on the T nut side fouling in the c/bore on the thrust side? is the thread on the diff screw short?

There has to be some thing It can't just not work!

[danielc3009]

Sorry I thought the grey bit I've circled was the head of the diff bolt but looking again I guess that's the nut holder. Is the bolt fully tightened in that picture as the gap between the nut holder and bottom of the slot looks too big, there should be almost no gap. I'd check that the spring and nut holder are correct, if your got the standard plastic nut try fitting it and see if the gap is smaller.

Also the b4 diff bolt and nut does fit in the 22 diff, I fitted one in mine when the losi nut kept coming loose

[daz75]

Originally Posted by danielc3009

Sorry I thought the grey bit I've circled was the head of the diff bolt but looking again I guess that's the nut holder. Is the bolt fully tightened in that picture as the gap between the nut holder and bottom of the slot looks too big, there should be almost no gap. I'd check that the spring and nut holder are correct, if your got the standard plastic nut try fitting it and see if the gap is smaller.

Also the b4 diff bolt and nut does fit in the 22 diff, I fitted one in mine when the losi nut kept coming loose

Spring looks fine haven't got the plastic nut holder unfortunately got the b4 bolt but it doesn't fit through the thrust bearing (think that's the name small washers with balls in the middle) so couldn't fit it wonder if it's the wrong thrust bearing and it's too big??

[jcb]

As Dan says the diff nut holder does look like it's too far out in the outdrive to me, it should be further in towards the main gear, in a similar location to the plastic screw cover you have where you are pictured holding the diff.

As Neil says can you build the diff without the main diff gear, tighten it fully and see if you can push the diff balls between the diff plates. If they slide in and fall out the diff halves are not being pulled together close enough.


I have also had it on a really one off occasion where the diff plates I bought were a smidge thinner than they should have been, meaning you could never get the diff tight enough.


For the sake of a few quid it may be worth while purchasing a new diff screw and plastic nut, just incase the screw is short or the nut carrier isn't allowing the nut to be pulled deep enough into the carrier.

[daz75]

thanks for all the help, decided to get an RTR gear diff and try that and it works, so whatever is wrong with the ball diff i'm not sure and i'm not good enough to fix it

At least my lads are happy, they were wizzing round the park with it yesterday

[NeilRalph77]

I presume you put some oil in it? Although it comes built it comes empty.

[Ashlandchris]

Interesting thread. I don't have a TLR, but logic says that the problem can only presumably be wrong thickness plates or wrong size diff balls? Is it something obvious like imperial/metric? Think TLR used to be imperial, but don't know now. I don't actually know whether diff balls come in different sizes.
Also, the bearing fitted in the main gear, if that is too wide it will prevent the plates coming close enough together presumably? Is there a bit of swarf or something just keeping the gap slightly too wide?