Rebuilding my R154 and have found some damage.

[kemicalx]

Hows it going all,

My R154 was making a shocking bearing noise in all gears and an even worse noise in reverse. I stripped down the box and found that the input shaft bearing was buggered, so i picked up a rebuild kit that contained all the bearings, seals and synchros then started the major strip down of the gear sets and replacement of the bearings, deglazing and replacement of the synchro's. I have however found some nasty looking contact damage inside the synchro ring (but not actually on it) on first gear, on the adjacent surface on the no.1 clutch hub. The back of the the 1st gear and the thrust washer has copped similar damage.













Damage cuts into the clutch hub and the thrust washer metal about 0.2-0.3mm using my finger nail gauge.. Damage on the 1st gear is hard to gauge, due to it gouging into the whole surface , ie. the is no lip i can scratch my finger nail over.

I am wondering if anyone knows how i should approach the problem? Could i take the damaged parts to a engineer/gearbox rebuilder and have them weld and re-machine the scoring then just replace the thrust washer, maybe with a custom machined up one? So far everything else in the gearbox seems in perfectly good order..

[cptsideways]

Those are the thrust washers that break up on 2nd gear especially, apparently Landcruiser ones are the same but tougher.

[kemicalx]

cheers mate, i have read a good article regarding their brittleness when exposed to fast and furious style shifting (or shock loading for that matter with a brutal engagement clutch) Didn't know about the land cruiser washer mate, thanks, i'll have to investigate that.

regarding the stock thrust washer (taken from mkiiitech who took it from supraforums.com)

The stock washer you gave me to analyse is made from a sintered material – most likely an iron/copper alloy. They do it this way at the factory because 1, it’s cheap and near net shape. 2, the sintered material is porous so lubrication is never a problem even if it doesn’t get oil all the time. The down side to the sintered material is it is extremely weak, with typical tensile strengths of around 300Mpa and it has very little fatigue properties.

The stock washer has been carbonitrided (a hardening process) about 0.2mm deep and has a surface hardness of about 52HRc.

My plan is to use a high strength carburising steel called EN39B (similar to the American grade 9310 but slightly better). This stuff is a 4.5%Ni Cr Mo steel and when carburised is extremely strong. Tensile strength will be up around 1300Mpa so it will take a lot more load than the stocker. The surface hardness will be 62HRc so wear resistance should be comparable to the sintered part. Carburising leaves a high compressive residual stress on the surface so fatigue life will be high and crack initiation difficult. The idea with carburising is you have a hard wear resistant skin on a tough high strength core so the part is not brittle.

Pretty much all of the parts inside the good transmissions (Hollinger, liberty, G-Force etc) are made from 9310 and heat treated this way, including the gears, shafts, thrust components and bearing races so I’m not reinventing the wheel.

Someone on the forum commented about a D2 washer breaking – that is because D2 is a high carbon/chrome tool steel. When it’s hardened it is full of huge chrome carbides and is very wear resistant but also very weak. It can only be through hardened so has no tough core to hold it all together, basically like a piece of glass.

On the subject of machining the nose off first gear… This is also a carburised part, the depth of carburising would be approx 0.6mm so you can't machine much off without breaking into soft metal – probably not the best option unless you want to try re-carburising etc, which whilst not impossible, will probably cause all sorts of distortion issues and noisy gears.

If I'm making a few of these I will probably CNC machine the majority of it so cost will come down a bit. All of the external stuff like material, heat treatment, surface grinding etc is a good part of the cost and something I don't have much control over so without going into too much detail I think we will be looking at about NZD$110 a piece.
If there is international interest shipping cost would be minimal because it could just be air-mailed in a small envelope.

Hopefully that will cover most of the enquiries until I'm back from holiday.

Regards,

Adam Walmsley

[kemicalx]

anyone here had experience rebuilding these gearboxes?

[EldarO]

i know Chris (Disturbed1) has pulled his apart once or twice due to munting the thrust washer.

[Disturbed1]

correct - i had similar damage to the surface which the thrust washer sits which unfortunatlly there is nothing u can do about it since u can only buy the hole first gear assembly which is around the 700 dollar mark

clean it up as best as u can and make sure the burrs are removed from around the oil gallery slots - looking at your pics it must be normal wear and tear as your thrust washer hasnt actually broken like mine had

r154s only have 1 repaceable thrustwasher which is the same as a landcruiser 1 remember to buy the little pin aswel for it

i just slapped in a factory toyota washer ($30) as its lasted 15 years.

[kemicalx]

Cheers mate,

I had another look at it today, the damage visible in pictures 1 and 2 is actually metal shavings that have collected on the surface, presumably from the adjacent surface on the clutch hub. Picking at it with a chisel it came away in pieces. So I'll give that as good a clean up as i can. I've had a couple of my lecturers at tradey take a look at it and they think that If i have to, I'll be able to get the clutch hub and the 1st gear machined down to a total of say ~1.5mm and then have a spacer ring machined up to slide in between the two.