Gracie. DISASTER. Transmission Failure.

**steane** · 7th March 2016, 07:49 AM

Originally Posted by MrLandy

Big call JC! In fact a very serious indightment coming from one of the best LR mechanics in the country.

If this is the case then no one buy a Ford Ranger or Mazda BT50 to replace their puma either.

My understanding is that apart from engine/gearbox, the only difference to driveline from previous Defenders is the rear diff? The problematic adapter shaft links the tried and true transfer case to new getrag gearbox. Once lubed or replaced no more problem?

Can I ask, what are the consistent puma engine / gearbox problems you're finding?

All Defenders have driveline clunk, all need HD flanges and rear axles at some point. All Defenders are prone to quirky behaviour, all have had factory issues and all 4WDs have their failings.

...How do puma electrics compare to problematic TD5 elecs for example?

DMax might be a great light duty work ute with a sweet engine but they look pretty flimsy as a long term rough country proposition to me.

Pumas must be really bad for you to come to this conclusion JC.

Ashcroft will tell you that the transfer in pumas is variable in quality at best.

My Defender does not have any driveline clunking. The 300tdi a friend bought last year that was original with 200k kms on it had no driveline clunking. The 2.2 Puma i had for a week a while back was great, but not as nice to drive as any of the 300tdis ive driven. More power but very hard to drive smoothly and way too much backlash in driveline to ever consider acceptable.

It was brand new...

Would still like to have it though, plenty to like about it.

**Pickles2** · 7th March 2016, 09:30 AM

Originally Posted by justinc

I have developed a list for these later models which now includes an Ashcroft ATB for the transfer case and a removal and lube of the yrans adapter in the same job. Next a change and inspection of the diff oils at 10k service. ANY sign of silver and we'll look closely at loose crosspins in the front diff and premature bearing failure for the rear diff ( p38a only in 110 and 130) and crosspin issues with the rear diff in a 90. Also a complete tightening of every suspension bush/ bolt and wheel bearing service/ change to oil lube hubs.

Jc

"Mechanically Hopeless" here, what is an "Ashroft ATB for the transfer case",...more particularly, what is an "ATB"?
Thanks, Pickles.

**Disco Muppet** · 7th March 2016, 10:29 AM

An ATB is an automatic torque biasing differential. Kind of like an LSD but instead of using friction plates it uses helically cut gears.
Ashcroft developed one to replace the centre diff in the lt230. If for no other reason, I'd fit one to eliminate backlash and strengthen the transfer case, particularly on a puma. But they also make things like fast gravel a delight to drive on I'm told.

http://www.ashcroft-transmissions.co...-atb-diff.html

Sent from my HTC One using AULRO mobile app

**rgty_kmj** · 7th March 2016, 03:21 PM

My March 2012 build 110 is too clonking away nicely at 43000 kms.

I too will be keen to get the Ashcroft MT82 Output shaft kit

but it looks like there are none in stock
Ashcroft Transmissions

(maybe heaps of people with this problem have the overwhelmed supply??)

Kerry

**cuppabillytea** · 7th March 2016, 03:46 PM

My Puma is an October 2013 build. It started service on Christmas eve 2013. I haven't been kind or respectful to her at all, apart from the yearly service and a twice yearly, or after severe mudding, wash and polish. She's had a few blown charged air hoses, the mandatory fuel tank issues and a few whacks. 43,000 Ks down the road now, but so far nothing in the drive train has broken. I suppose I'll just keep flogging her until something goes bang and then fit the Ashcroft gear.

**PAT303** · 7th March 2016, 04:48 PM

Originally Posted by ProjectDirector

I said "Frankenstein" from the perspective of putting parts together that have little engineering input. I am an engineer and been involved in many engineering designs.
LR obviously did not have design funds for defender and therefore quickly took parts from existing pile and adapted them.
Why do you think the bonnet has a bulge? They had to place the engine higher to line up the drivetrain.
Anyway I still like my defender and will fix the drivetrain design flaws with Ashcroft and hand the car to my son as I was about to sell it and he put his hand up.

The adapter is not under engineered,it's under lubed

,now that I've said that we will leave it or we'll have the worst thread drift possible

. Pat

**YOLO110** · 7th March 2016, 05:34 PM

Originally Posted by jackdef90

Attachment 106600

Attached is Photo of the culprit, was changed about a year ago...

I have looked at the photo's many times... and every time I do I come to the same observation...

Grease or no grease, the actual DEPTH of the grooves look far too shallow to me! As do the height of the tongues on the output shaft.

Whilst there are a lot of interface sections, it seems that the interface area is small, especially considering the load transfer forces that are exerted each way. Would it not be a much better and totally robust design if the depth of the grooves and height of the tongues was increased...?

Or am I missing an engineering issue with this? Obviously there is a maximum height/depth given the rotational circumference restrictions... but what I see just 'looks' rather puny and I am not surprised we have failure at this point...

Thoughts?

**ramblingboy42** · 7th March 2016, 05:49 PM

A spline is far stronger and normally more durable than a spigot.

Without being mean you are missing an engineering issue.

A spline is usually used where good radial power is transmitted in a fixed position....a spigot is used where the power is transmitted radially and laterally.....however both should still be lubricated.

A spigot will always have more backlash than a spline.....unless worn of course.

**YOLO110** · 7th March 2016, 05:57 PM

Ok! I am not an engineer so thanks for the input.

Curious, when does a spline become a spigot? Is it not possible to increase the depths of the design and would that not spread the loads to eliminate this fretting to failure issue?

**JDNSW** · 7th March 2016, 06:57 PM

No, as pointed out, the problem is lack of lubrication. The area is actually quite large - each tooth is small, but there are a lot of them, and they are fairly long. And they are at a relatively large radius, which reduces the load per tooth. Compare to the spline on the other end, inside the transfer case, which has the same load. Fewer but deeper splines, I suspect you will find though that this one has a larger contact area, mainly because it is on a larger diameter, as well as a lower load.

Perhaps worth pointing out that a similar problem in the same position has arisen many years ago with the drive to the Fairey overdrive on Series Landrovers! This has a very similar spline! And also is prone to a lack of lubrication.

John

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