At last - I have found the problem with my transmission.

[Chris]

Got some Prussian Blue now and with pinion shim pack coming sometime this week, I should be able to crack on and finally get this rebuilt.

 

[Chris]

Well despite the Prussian Blue (Loverly plumage) and a massive bag of shims from the good Doctor, I still can't really see a contact pattern.

I dropped .2 off the first shim, noted the smudgy marks, then went up .1 which seems to have moved the pattern if I can call it that roughly to the middle of the tooth which would make sense in that the 0 position shim had the smudge roughly full deflection the other way. It all adds up. New bearings, slightly taller, thicker etc needs thinner shim to put it all back. It feels superb, but as far as a contact pattern is concerned? Very hard to determine. I have to chalk this up to having run-in ring and pinion, with the collapsed bearings and adjustments leading to a much larger contact area than a new set.

Bearings - new and settled in
Pinion pre load - measured spot on
Backlash - measured within tolerance
Carrier preload - measured within tolerance

Pattern, errm pattern? I said PATTERN????? Cooooeeeeee

Very very very hard to see. It just tends to wipe the whole lot off.

But what I can say is that the original shimming was good, the thinner shimming was good, but the middle shim is silky smooth. Even with some load on all I could hear was the whizz gun driving it. So I think I'll chuck it back in and go for it.

 

[frank rabbets]

I think you need the least possible marker. Or even less.

 

[Chris]

Well I think it's safe to say it's good news. Been messing with this diff for weeks trying to get a pattern out of it. Today in utter frustration, I pulled it apart and put the old bearings back in to try and measure the original pinion depth. It's a little crude but gave me a comparative reading from which to work out the best shim thickness. Thanks again to JW for the loan of his shim library.

At this point my press decided to go on strike so I spent an hour topping that up and trying to bleed it. So, all pre loads in range and back lash set, I got the nearest to a pattern that I've really had so far, not perfect by any means but these are gears that are worn, but that have also been running with a wonky bearing as we know so the pattern was always going to be more of a smudge than a spot.

At 15.30 standard Brexit time, the jack went under the axle and at 17.30 UK tea time, it set the truck back on it's wheels. 2 hours for a full hub, axle and diff strip - rebuild has to be pretty good. So what's the result.

Man that's quieter. I mean really quieter. It's so smooth and on the over run there's no banging. There is no difference at all in the tone between drive and coast in the diff. And after a run, the diff pan wasn't even warm.


And Yes Frank, I PUT THE OIL IN!!!!

Thanks once again to JW and to Trevor for the use of his tiny little TOOL.

 

[karl webster]

Great news Chris

 

[Chris]

It needs a run in and a good road test Karl, but fingers crossed for a smooth ride from now on. I bought a load of heat insulation and sound deadening for the floor of the cabin so with that in, we should be living in luxury.

 

[AndyCook]

Job well done

 

[clivehorridge]

Nice one Chris, well worth the effort!

Let's see how it goes when it's run-in...

 

[Jon Wildsmith]

Good news Chris, well done for sticking at it!

 

[Chris]

Thanks guys. Well it's either this or back to turning tricks for sailors down at the docs. No idea what I'll do once it's all perfect.

 

[Chris]

I'm in love again


Oh my goodness. What a difference. This is the 80 I always wanted. Damn that's so quiet. Even at 70 with all the kit on the roof, it's quiet. There's no noise to mention. It's beautiful. When I think what it was like through Morocco and round the Baltic, this is gorgeous.

I have installed some additional sound and heat insulation this morning and it's even better. Not hot left foot anymore. I'll post that on my build thread later. But in the meantime I am going out for another drive because I'm so excited.

 

[JamesSab]

This is an interesting forum for sure. Hahha I cant stop reading all the random. xD

 

[Chris]

We like a good thread resurrection. As a foot note to this, for anyone trying to pattern a diff themselves, it's worth mentioning that I gave up on Prussian Blue and other supposed gear marking paints. In the end, I went to an art shop and bought bright yellow oil paint. Small tube was like £5.00 which wasn't cheap but man alive it's perfect. Brilliant stuff. You hardly need any, it's easy to apply, easy to remove and gives really clear readings. New ring and pinion gears are much easier to read, but worn ones, especially badly worn ones, are sometimes very hard to read as the engagement points have merged into one across the faces.

 

[frank rabbets]

You'll need a bigger tube Chris.

 

[Dave2000]

I agree using the yellow paint, used it when checking out problems with my Discovery fiffs, works soooo much better.

regards

Dave

 

[clivehorridge]

I agree using the yellow paint, used it when checking out problems with my Discovery fiffs, works soooo much better.

regards

Dave

I’d love to have a proper front diff rebuild, I’m sure the wining I get is from the diff, it doesn’t even go away when the missus gets out...

 

[Chris]

Pop it round Clive and I'll sort you out at mate's rates.

 

[clivehorridge]

Pop it round Clive and I'll sort you out at mate's rates.

Be careful what you wish for Chris, one day (not soon) I might just take you up on such a kind offer

 

[Chris]

I think I am out that day Clive. Getting my nails done I believe. Shame otherwise you know I'd have helped out.

 

[thelal]

Errm, any metallurgists out there? It's only the main carrier bearing. All the others are fine. Not every roller is like this, most yes, but it's an odd pattern.
These were original OEM Koyo bearings. So hopefully a clean and tune up and it will be back in action.
.

you think it was faulty rollers in the bearing?