Driveline/ Gearbox Noise when Unloaded in 6th

[The Cone of Silence]

A peculiar sound has developed of late. I know, Defender forum...noises are common...but this one I haven't yet found in a search.

2008 Puma 110.

I noticed the noise while driving out to Forbes a couple of weekends ago and it occurred on the way back, too. I replicated it driving from Richmond to Sydney on the M2 on Sunday so it's not a one-off.

100kph in 6th gear. If I'm about to go down a gradient on the freeway I'll back right off the throttle as I don't want the car to accelerate above the speed limit. When the driveline is completely unloaded like this, there's an rattly sound which I think is coming from the gearbox or perhaps the transfer case....it's not a happy noise though.

As soon as I load up the driveline with even a tiny bit of right foot, it goes away...that is to say this noise only occurs when there is no load at all being pushed to the axles.



This noise only occurs in 6th gear, I've been unable to replicate the rattle in 5th or lower.
The noise sounds like something is loose and being shaken about.
Power and drive are not affected. Engine temperature is not affected. I can't check gearbox oil or transfer case oil temps.
Clutch is only 20,000kms old,m if that.
Transfer case was rebuilt at KLR 2,000kms ago and has an Ashcroft ATB in it.
Driveline has had new HD shafts, flanges and Ashcroft ATBs front and rear only 2,000kms ago.


Your wisdom and experience would be greatly appreciated.

I've got to take Monty to KLR next week to get an ABS relay replaced (3 amigos have been illuminating my dash for the past 2 months) so if we can diagnose this a little before he goes in, it might help Brad and the boys to get to it quickly.

Cheers

[Rolly]

Mine made a very similar noise. It turned out to be a rear diff which started to eat itself when bolts fell off within. See my thread on driveline noise when foot off accelerator.
Rear Diff replaced under Warranty.

Good Luck!

[MLD]

Hi Bobby,

My 2 cents, you have a shot 6th gear. Extend your research to the Ranger forums. Lots of complaints about broken manual boxes which you might recognise a similar symptom. Ranger owners complain about 6th failing in the MT82 when towing or carrying weight. You, my friend, qualify for carrying excess weight and if you lug in 6th you are a candidate. Unfortunately replacing 6th is a full rebuild. When i was researching the 3.2 conversion i was told by Ashcroft there is no upgrade to the MT82 to strengthen it. Might be different with the passage of 24 months so worth asking the Q.

I would have thought that a rear diff under coast would be noisey in every gear. More noticeable at higher speeds the higher gears but the symptoms wouldn't differ between gears. I have a noisey rear diff and taped my iPhone to the diff housing and went for a drive to record the sound. Bill from GBR thought i was nuts but appreciated the accuracy of the information.

[The Cone of Silence]

Hi Bobby,

My 2 cents, you have a shot 6th gear. Extend your research to the Ranger forums. Lots of complaints about broken manual boxes which you might recognise a similar symptom. Ranger owners complain about 6th failing in the MT82 when towing or carrying weight. You, my friend, qualify for carrying excess weight and if you lug in 6th you are a candidate. Unfortunately replacing 6th is a full rebuild. When i was researching the 3.2 conversion i was told by Ashcroft there is no upgrade to the MT82 to strengthen it. Might be different with the passage of 24 months so worth asking the Q.

I would have thought that a rear diff under coast would be noisey in every gear. More noticeable at higher speeds the higher gears but the symptoms wouldn't differ between gears. I have a noisey rear diff and taped my iPhone to the diff housing and went for a drive to record the sound. Bill from GBR thought i was nuts but appreciated the accuracy of the information.

I think you might be right Mark...I was struggling to reconcile the rear diff issue that Rolly had being the same on Monty on the basis that it's only on unloading 6th gear that I get the noise and the fact that the rear diff only got put back together with an ATB a couple of thousand easy kms ago.

The car is 3 tonnes so yes, he's a bit on the gentlemanly side of 'svelte' and while I don't lug 6th gear these days, I did used to when I first had the car so perhaps it is indeed a shot gear.

Everytime I look like getting the last fix paid off, Monty kicks me right in the Jatz...

[MLD]

Every time I look like getting the last fix paid off, Monty kicks me right in the Jatz...

I feel your pain. Drove back from VHC on Sunday night and at Goulburn for fuel she wouldn't idle (stalling). Nursed her home and on the way home last night it stalled at a major intersection in Wollongong. Wouldn't start. Had to push her out of the way then flat bed her to my mechanic. Add insult, the Audi is in the workshop for a gearbox rebuild. 2 cars, both expensive, none working.

[The Cone of Silence]

2 cars, both expensive, none working. Ouch.

[DiscoMick]

If it was rattling when idling in neutral I'd suspect the clutch springs, but that doesn't sound like your symptoms.

[The Cone of Silence]

If it was rattling when idling in neutral I'd suspect the clutch springs, but that doesn't sound like your symptoms.

Correct mick, idling in Neutral even at that speed is fine in terms of noise. It's only when I'm in 6th gear, all pedals are free from feet and there's no load on the drive. Clutch was replaced not that long ago.

I almost wish it was a diff - all three would be under warranty!

If it is indeed a gear and the box needs a rebuild, it it safe to assume it's worth replacing clutch and slave cylinder while the box is out?

[MLD]

if it is a gearbox, the manual from a BT50 and Ranger is the same box so you might be able to save $$ by hunting down a box from a wrecker if you are willing to take a risk on its history. I'm using Wollongong Automatics and impressed by their customer service and knowledge. They have a few ZF 6HP26's laying around if you wanted to go auto. There are adaptors for the LT230 floating around.

[The Cone of Silence]

It's tempting to go second hand but I'd rather pay the extra and have it rebuilt with new teeth and shafts and bearings.

What's properly tempting is the auto conversion....I might have a chat with the lads at KLR (and Ashcrofts) and assess options.

Incidentally the latest from Dave himself today: "yes 6th is a weak point of the MT82 but I can’t see a way of making it stronger, you are restricted by the width of the gear teeth," so i guess the last 24 months have not been spent in R&D for the Puma 6th gear weakness.

[alan48]

Hi,
if you do have any luck re discussions on an auto please PM me as I too would be interested--so far most people I have spoken who have tried to do auto pumas have had lots of issues and say not to do it--yet I know Grinna in Wauchope who has been developing the 3.2 conversion into the pumas has also started development on an auto conversion, but have not heard from him in a while. Some of the leading LR independents feel the conversion to auto problematic, but I am hopeful. Please keep us all informed! Incidentally, Award Diffs in Seven Hills are puma gearbox experts and do some of the dealer's warranty rebuilds--I know because they did my son's--maybe give them a call--they have done a LOT. Thanks,
Alan [bighmmm]

[MLD]

Hi,
if you do have any luck re discussions on an auto please PM me as I too would be interested--so far most people I have spoken who have tried to do auto pumas have had lots of issues and say not to do it--yet I know Grinna in Wauchope who has been developing the 3.2 conversion into the pumas has also started development on an auto conversion, but have not heard from him in a while. Some of the leading LR independents feel the conversion to auto problematic, but I am hopeful. Please keep us all informed! Incidentally, Award Diffs in Seven Hills are puma gearbox experts and do some of the dealer's warranty rebuilds--I know because they did my son's--maybe give them a call--they have done a LOT. Thanks,
Alan [bighmmm]

Award Diffs closed last year.

The 6R80 auto from the Ranger and BBT50 protrudes on the drivers side affecting clearance of the front prop shaft. The ZF 6HP26 is slimmer and might not pose the same problem. Sorry Bobby for the off topic

[Beery]

I think the bigger, heavier pumas need slightly different gearing to the standard. 6th gear doesn't let the engine rev high enough for 100 - 110km/h.
To get around the strength problem of 6th, I'd like to re-gear my driveline to cruise in 5th which is direct drive. Either by changing the high gear of the transfer case or larger diameter tyres.

[DiscoMick]

Mine is doing about 2100 revs at 100 kmh in 6th, and quite happy from there upwards.
I think the real problem is when people let it go too slow in 6th, down to 80kmh or even lower. At 80 kmh I find it is much happier in 5th. Its not an auto and the gears have to be used.

[Beery]

Mine is doing about 2100 revs at 100 kmh in 6th, and quite happy from there upwards.
I think the real problem is when people let it go too slow in 6th, down to 80kmh or even lower. At 80 kmh I find it is much happier in 5th. Its not an auto and the gears have to be used.Exactly. I don't like going under 100 in top gear unless coasting down a grade or with very light load on the engine.
I wish someone made a miniature Road Ranger gearbox that would fit in these.

[The Cone of Silence]

Exactly. I don't like going under 100 in top gear unless coasting down a grade or with very light load on the engine.
I wish someone made a miniature Road Ranger gearbox that would fit in these.

I used to be terrible at going too slowly in 6th but after a great weekend with Chook and Summit, I stopped using it until I was doing at least 100kph.

Will assess options and if I go down the auto route, I'll keep everyone updated.

[The Cone of Silence]

Well, I took a punt and ordered a new gearbox from Ashcroft, with the shaft upgrade added. The boys at KLR installed it along with a new clutch just in time for my drive up to Bundella last weekend and unfortunately I can report that the noise is still occurring, in exactly the same conditions....100kph+ in sixth gear, on flat or decline, foot removed from loud pedal. Rattly rattly not ouchy grindy. Definitely seems to be coming from the left of me and toward the front but I can't determine if it's the box, the diff or the engine.

I've shot Ashcroft an email to ask for their thoughts.

Next potential culprit could be the front ATB I suppose (I don't recall ever having heard the noise prior to having the ATBs installed) but I struggle to see how an issue in the diff housing would only occur at 100kph in gear unloaded but not with the clutch in or in neutral.

Feeling decidedly deflated.

[Phil B]

Bobby
May sound stupid but I’ve heard of similar symptoms that turned out to be a loose plate rattling inside the cat. converter

[MLD]

Bobby
May sound stupid but I’ve heard of similar symptoms that turned out to be a loose plate rattling inside the cat. converter

Hey Bobby, if that was the cause wouldn't it just compel you to stick a hot poker in your eye while clamping a vice on your money bags?

[The Cone of Silence]

Bobby
May sound stupid but I’ve heard of similar symptoms that turned out to be a loose plate rattling inside the cat. converter

While the box was out they also cut the cat out so this can't be the culprit, but I appreciate the suggestion, thank you Phil.

Dave Ashcroft has suggested that it could be the front diff and to remove the front prop shaft and see if the noise still occurs. If it does turn out to be the diff I'll assume it's a warranty fix as KLR installed the ATB and HD shafts and flanges etc only a few months ago.

We shall see....

Currently waiting for Brad to source me a second hand ABS pump for an unrelated issue so once he's got one of those, I'll take it in and we'll have a good look at it.

[MarkM]

Mine has just started to grumble under load in 6th.

I thought gearbox, but I find that when i squeeze the rubber boot at the base of the gearstick it goes away, so now I am pretty sure it's this...

DEFENDER2.NET - View topic - Puma Gearstick rattle / vibration cure guide (with photos) (http://www.defender2.net/forum/topic27350.html)

Regards
M

[The Cone of Silence]

Mine has just started to grumble under load in 6th.

I thought gearbox, but I find that when i squeeze the rubber boot at the base of the gearstick it goes away, so now I am pretty sure it's this...

DEFENDER2.NET - View topic - Puma Gearstick rattle / vibration cure guide (with photos) (http://www.defender2.net/forum/topic27350.html)

Regards
M

Dude if it turns out that I just spent $6,000 when I could have spent $1.45 on some superglue from Bunnings, I'm going to be so sore!

[MLD]

Dude if it turns out that I just spent $6,000 when I could have spent $1.45 on some superglue from Bunnings, I'm going to be so sore!

Shall i repeat my comment below?

[YOLO110]

Mine also had this 6th gear rattle... and as it turned out, these 'rattly weights' at the base of the gear stick from new.

As stated, an easy fix... glued the weights in place and no more rattly noise!

But a gearbox/clutch/Ashcroft drive upgrade is not a bad thing either! :thumbsup: