Cougar Diff . . . . .Again!!

Click · #1 31-01-2012

Hi Lads,

I did a search and had a read of other posts about the diff & have looked at various online vids about rebuilding.

This is what I've done:

1. Sanded diff rings using 600 paper + some WD40, kept sanding using one of the outdrives until I got a grey surface all around
2. Used new diff balls
3. Used new diff screw and conical washers + new circlip
4. Used black grease on the thrust washer
5. Used diff grease on the balls & diff rings
6. Tightened up diff fully tight & backed off 90 degrees

Diff still feels very 'gritty'?

I have another diff not built by me & it feels a lot smoother, I'm just trying to figure out what I'm not doing right?

With the circlip, I've spread the clip so there is a 4.5mm gap and did my best to get it positioned without squeezing it too much but it still feels loose in it's grove. I'm also aware there are two sides to the clip and have it orientated correctly.

So, Schumacher guru's what am I doing wrong? Why is my diff still gritty

bigred5765 · #2 31-01-2012

try adjusting it till it doesnt feel gritty and make sure it isnt slipping

Click · #3 31-01-2012

Hi,

Thanks for the reply. If I back off the diff screw, so the gritty feel is gone, the diff slips too easily

bigred5765 · #4 31-01-2012

depends on what you call gritty, it isnt suposed to be like a geared diff as long as it doesnt feel notchy or clicky it may be ok, you probably need someone with a little more experiance to look at it i think,

h0m3sy · #5 31-01-2012

If your going to the Naul on Sunday, bring it over and I will take a look for you.

Click · #6 31-01-2012

Quote:

Originally Posted by bigred5765

depends on what you call gritty, it isnt suposed to be like a geared diff as long as it doesnt feel notchy or clicky it may be ok, you probably need someone with a little more experiance to look at it i think,

Once again thanks for the reply. As I said I have another diff which is super smooth compared to the one I just rebuilt, so I already have a ref. 'feel' for what it should be like.

The club I race with have some very knowledgable lads, I just thought I'd have this sorted before next weekend.

Click · #7 31-01-2012

Quote:

Originally Posted by h0m3sy

If your going to the Naul on Sunday, bring it over and I will take a look for you.

Will do, it's just a bit annoying, I'm doing everything, I think, by the book but just can't get it dialed in right.

Some forums say the circlip should be so tight that you can barely move it with a screwdriver, mine moves very easily, could this be the issue?

See you on Sunday

Mugenextreme · #8 31-01-2012

Is there any gap between the bottom of the clip and the plate from the thrust bearing?

Click · #9 31-01-2012

Quote:

Originally Posted by Mugenextreme

Is there any gap between the bottom of the clip and the plate from the thrust bearing?

Hi Colin,

Just had a look, seems fine, clip is tight against the 'cup' that goes in last on top of the cupped washers (weird design why didn't they use a spring

)

I spread the circlip again and got it in without bending it back together, it's a lot tighter now, I can't move it with a screwdriver once its clicked in place.

Diff now feels a bit better, we can all have a feel of each others diffs on Sunday

Thanks for all the advice.

MattW · #10 31-01-2012

So, your main plates are good, your diff balls are good. However, you haven't changed the thrust race as far as I can tell. If you haven't, then I would 100% recommend replacing it - and I would use this one:

http://www.racing-cars.com/pp/New_Ca...4CX/U1954.html

This is by far the best thrust race that Schumacher have, and it's one that some other manufactures drivers choose to use in their diffs as well

I think this is a different one to the one in the kit, but it definitely fits.

What you could do to try and fault find a little more is swap the assembled outdrive from your good diff, with the assembled outdrive of the bad diff. This will tell you that it's something in that assembly - and you've changed the springs!!

Click · #11 31-01-2012

Quote:

Originally Posted by MattW

So, your main plates are good, your diff balls are good. However, you haven't changed the thrust race as far as I can tell. If you haven't, then I would 100% recommend replacing it - and I would use this one:

http://www.racing-cars.com/pp/New_Ca...4CX/U1954.html

This is by far the best thrust race that Schumacher have, and it's one that some other manufactures drivers choose to use in their diffs as well

I think this is a different one to the one in the kit, but it definitely fits.

What you could do to try and fault find a little more is swap the assembled outdrive from your good diff, with the assembled outdrive of the bad diff. This will tell you that it's something in that assembly - and you've changed the springs!!

Hi Matt,

Many thanks for the tip on the thrust race. You are correct, I did not replace this race nor did I change the bearings.

Once again thanks for the advice.

Mugenextreme · #12 31-01-2012

Quote:

Originally Posted by Click

Hi Colin,

Just had a look, seems fine, clip is tight against the 'cup' that goes in last on top of the cupped washers (weird design why didn't they use a spring

)

I spread the circlip again and got it in without bending it back together, it's a lot tighter now, I can't move it with a screwdriver once its clicked in place.

Diff now feels a bit better, we can all have a feel of each others diffs on Sunday

Thanks for all the advice.

They just use a different system by using the cone washers linked to act like a spring . Could be the trust bearing , we can check it out at the track.

spud31 · #13 31-01-2012

Just checked mine same feeling has melted the diff balls into the gear

When you rebuilt yours did the balls fall out of gear easily ?

Rich D · #14 31-01-2012

It's not impossible that your new balls are to blame. After following matts advice I'd suspect these next. Had the same trouble recently myself

dmcracing · #15 01-02-2012

Bring it over to me on Thursday nite,and I will sort it.And show you to set the diff for 10.5T

paranic · #16 01-02-2012

here is how my diff plates look after 4 weekends of practice.
they look extremely cruncy :-)

i will assemble them like this for another weekend and then flip them over for the race

john333 · #17 01-02-2012

I would say the diff is set too tight, mine would look like that after much more racing than that. Only my opinion from the photos though! ;-)

paranic · #18 01-02-2012

yes that's what it felt compared to my rear from my B44
maybe it needed more than 90 deg unscrew
i followed the manual and not my feeling on the hands.
+ i didn't put that extra screw on the back to close the diff case gap!
it wasn't on the manual !

lochness42 · #19 01-02-2012

One thing that most people having diff issue don't do is running in diff.
If you can get some broken driveshaft from your TC mate you can put it in electric screwdriver or drill and continually tighten it in between holding diff in center and spinning it with driveshaft at low rpm. That way everything beds in without too much stress on parts and you should end up with very nice diff. If you put too much stress on bits - you might will need to replace them and try running in diff again. You should stop once diff isn't slipping.

Click · #20 03-02-2012

Quote:

Originally Posted by dmcracing

Bring it over to me on Thursday nite,and I will sort it.And show you to set the diff for 10.5T

Hi Lads,

Really appreciate all the replies. Been out of action for 2-3 days so could not make the Naul on Thurs & it might look like I won't be able to race on Sunday due to a hand injury

BUT hopefully I'll have a perfectly setup diff once Derek works his magic

Kevin