Discovery 4 Transfer Case Slop / Thud on Engagement

[eddielines]

Following on from Discovery 4 Tailshaft / Rear Propshaft Wear and Replacement (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/297527-discovery-4-tailshaft-rear-propshaft-wear-replacement.html) I have replace the rear prop shaft and it hasn't resolved the drive line thud or slop, however because it has tightened up part of it it has allowed me hone in on the issue.

I still get the slight thud / slop when off accelerator and back on. I now can also hear a slight thud when changing from reverse to drive.
I've gotten under neath while some one changed gears and confirmed it is from Transfer Case. See attached video

I will plan to take it into to get seen by Indy, but has anyone had similar and clarify based on the noise whether in their case if TC itself or spline wear between Trans and TC.

Note the transmission was rebuilt 18 months ago and I will check with them but I would assume output spline and greasing this would be part of the Trans rebuild, although the input shaft on TC would not be replaced with rebuild ?

When they rebuilt the Trans they did also drop and split TC. to replace front output seal. I will have to check but I believe they used the same fluid as the Trans in the TC, this would appear not to be to spec but reading it appears people do put ATF in as it has clutch packs, etc. I have checked about a month or 2 back and the fluids were all clean and no shavings. I could replace with spec oil to see if it makes any difference ?

[eddielines]

File attached.

[DiscoDB]

ATF is definitely the wrong fluid.

I would recommend changing to the correct fluid, or try Ravenol DTF-1 as this is known to solve TC issues in BMW and Porsche transfer cases.

A calibration of the Transfer Case Control Module may help as it resets the control module to the current clutch pack dimensions. Normally only needed if components have been changed, or the calibration settings have been lost.

[DiscoJeffster]

Driveline thud. It’s a disco thing as they age. No one can definitively tell me what causes it. I have it too, and generally find I can drive around it, but for me it’s worst when coasting down a slope, then apply acceleration. This seems to be a case of engine braking then onto power leading to a big negative then positive transition with the largest thump. I’d pay almost anything to solve it.

[eddielines]

Just to clarify, the Trans was rebuilt. I only had them replace a seal on the TC that had a very slight weep, as it was would be off to get teams off anyway
To replace the seal they would have had to drop oil and split, thus new fluid after for that as well as the rebuilt trans.

[eddielines]

I have an IID and did calibrate myself a while back as I read that cures some issue. I will replace the oil ( can get RP synchromax handily which seems to meet spec.and used by many).

Thanks DiscoJeffster it's a relief to know it's not uncommon and I don't need to panic about it. Its a pity though as the comfort and drivability is a big part of what sets these cars apart and this takes away a little from that.


I've also read on this forum that spline regreasing may solve, based on a slight whistle I think I am developing, I think I am up for Manifold leak Cross over leak, so will get them to check spline for play and regrease also

I also read on Disco3 UK forum someone replaced pretty much their whole drive line before it got solved with front prop shaft replacement which had only very minor play.

While I think I have the slightest of play in the front prop shaft in my case I can now reproduce clunk in TC case with the shifting back and forth between Drive and Reverse on brakes,

[DiscoJeffster]

Past experience shows it’s not the transfer case sadly. Check this thread from a few years back

https://www.aulro.com/afvb/l319-discovery-3-and-4-a/279240-high-kms-transfer-case.html

[PerthDisco]

It would be logical the internal chain in the TC would stretch and introduce a slop.

[DiscoDB]

It would be logical the internal chain in the TC would stretch and introduce a slop.

Transfer Case chain replacement due to stretch (or technically wear) is a pretty common repair needed on many other brands which use the same style of box, but not something you see regularly with the D3/D4.

Eventually the chain will stretch to the point that they will even skip teeth, but yet to see any reports of this being common with the D3/D4, even for high mileage units.

The D3/D4 must have some sort of special oil in it…[emoji106]

[loanrangie]

Transfer Case chain replacement due to stretch (or technically wear) is a pretty common repair needed on many other brands which use the same style of box, but not something you see regularly with the D3/D4.

Eventually the chain will stretch to the point that they will even skip teeth, but yet to see any reports of this being common with the D3/D4, even for high mileage units.

The D3/D4 must have some sort of special oil in it…[emoji106]


Unicorn tears by the price of it.

[DiscoDB]

Unicorn tears by the price of it.

…and a sprinkling of Unicorn Horn Dust as a magic friction modifier. [emoji882]

[PerthDisco]

…and a sprinkling of Unicorn Horn Dust as a magic friction modifier. [emoji882]

You could buy it from Advanced Factors at a reasonable price previously but now they stock the Ravenol option I think from last time I checked.

[DiscoDB]

You could buy it from Advanced Factors at a reasonable price previously but now they stock the Ravenol option I think from last time I checked.

If I couldn’t get the LR oil, I would probably change to Royal Purple Synchromax. Just doing an oil change now, so next one won’t be due for many years yet. A lot can change by the time it is due again.

[eddielines]

Thanks guys, I will get underneath this weekend again

Is there anyway to try and narrow down whether trans to TC sines or front or rear output from TC. E.g. remove prop shafts one at a time and check play but also changes in noises when engaging when switching from D to R and back ?

I also notice when coming of the accelerator at lower speeds sometimes there is a bit of a clunk and the rpms drop very quickly from say 1500 down to idle rpms. I assume this is a bit of engine breaking and the clunk is just whatever the backlash is being exposed, gear changes overall are smooth it's just this one scenario/range where it feels like the rpms drop quicker than they used to.

Something just doesn't feel right.

I might also get in and check and clean sensor down at accelerator and clean throttle body.

Trans rebuild was done about 20 months ago and serviced 9 months ago to keep the 2 year warranty, I will also check the fluid level of trans.

[eddielines]

Ok, so got back under this weekend.

Check trans fluid level, no issue there.

Looking for play although some noise in Transfer
Case moving from D to R and back it's not bad and doesn't feel like significant play or clunk is there, even though that's where I thought it was the last day.

Playing around it appears there is only very slight radial play in front prop shaft, but easy to push / pull or forward / back play see video.

Also front right half shaft seams to have very little radial play when I try to rotate the shaft, but play in the housing that covers the inner cv and also there is up and down and side to side play on that housing,.see video, is this normal ? is that likely to be the issue ? I've read elsewhere that this is expected to some extent it's the rotational play on shaft that's an issue

[eddielines]

Transfer play / noise D to R and back

[RANDLOVER]

Unicorn tears by the price of it.


…and a sprinkling of Unicorn Horn Dust as a magic friction modifier. [emoji882]

Which are mixed together by a leprechaun.

[DiscoJeffster]

Ok, so got back under this weekend.

Check trans fluid level, no issue there.

Looking for play although some noise in Transfer
Case moving from D to R and back it's not bad and doesn't feel like significant play or clunk is there, even though that's where I thought it was the last day.

Playing around it appears there is only very slight radial play in front prop shaft, but easy to push / pull or forward / back play see video.

Also front right half shaft seams to have very little radial play when I try to rotate the shaft, but play in the housing that covers the inner cv and also there is up and down and side to side play on that housing,.see video, is this normal ? is that likely to be the issue ? I've read elsewhere that this is expected to some extent it's the rotational play on shaft that's an issue

Front left inner CV is known to wear and have lots of play. I have replaced both my front CV shafts recently due to the slack/wear in forward/reverse drivetrain direction, but didn’t change the clunk.

[eddielines]

I think that front right needs changing, left has no play in any direction.

I also think the front propshaft has had better days.

What did you replace with ? genuine or other ?

Have you put ears or eyes underneath to track down ?

I agree with you it's head wrecking and keen to try and get rid of it.

[DiscoJeffster]

I think that front right needs changing, left has no play in any direction.

I also think the front propshaft has had better days.

What did you replace with ? genuine or other ?

Have you put ears or eyes underneath to track down ?

I agree with you it's head wrecking and keen to try and get rid of it.

Some aftermarket shafts

I’ve given up. I think it’s the gearbox. If you look up issues with the gearbox thuds and clunks are very common across lots of different wear issues.

[Eric SDV6SE]

Seems to me the cv joint, specifically the cross that retains the spherical bearings is worn. I understand these can be rebuilt. Replacement crosses and bearings can be bought. An easier approach may be a complete new propshaft.

[DiscoDB]

Something just doesn't feel right.



That alone is a good enough reason to keep investigating.

[eddielines]

Thanks Guys

Yep, got car off wheels last night.
Compared play and feeling of take up if slack in each inner cv. Nothing more than I feel would be expexted in rear. Front let a little bit although very minimal. Front right not massive like I see in videos but some obvious play.

Plan of attack is replace front right and if that helps but does solve it, then front left and if not fully solved have a good look at front prop.

I saw the rebuild kits for inner bit due to time will just replace I think.

@discojeffster I am still under warranty for trans rebuild if I think it's that I will be going back to them.

[eddielines]

Just providing update for anyone that may be having the same issue.

Took it into Indy. He thinks it is the Transfer Case internal. He is going to change to OEM oil and if that doesn't help the recommendation is to replace with low KM 2nd hand that's had an easier life .

[Eric SDV6SE]

Royal purple sunchronax transfer case oil is as good as the oem snake oil. I ran it in my D4 SDV6SE transfer case for 60k km without issue. Slop is from mechanical wear, typically the splines. Try removing them and applying a liberal amount of grease. If intermal, i.e stretched chain in thr transfer case, then no amount of oil can fix that.

[eddielines]

To close this out, mechanic is sure its the transfer box (chain), but its not that bad compared to a lot that people are doing nothing about. So I've decide to live with it for now, its not that bad, I barely get it with feathering accelerator, just working on that with my better half.

If it gets any worse I'll have them pull the Transfer case off and check splines and consider a low km replacement.

[eddielines]

I'd also like to thank those that replied to my questions and contribute to this forum in general.

While I've never been into cars or mechanically inclined historically I'd consider myself reasonably competent and doing more and more since I bought the car 5 years ago. It wouldn't be possible with out this forum and its contributors and the Disco3 site in the UK.

Now if only I had somewhere I could put a lift !

[eddielines]

Was checking out suspension and drive line as part of latest service. Bushes in front upper control arm on Drivers side are shot. Not sure why I couldn't see this when looking back then. Will loop back to confirm when replaced next week.

Oh, and I have a little grease on seam of front prop shaft and can find a minimal amount of play in it so that will be replaced now also. Has anyone replaced prop shaft with anything other than genuine of GKN and been happy with it, anything I've read said GKN new or low milage genuine second had ?

[PerthDisco]

I’ve been chasing a thunk in front also and recently did tie rods. Next is upper arms have new bushes ready to go.

Interesting on LR Time yesterday same issue same diagnosis after doing tie rods.

Shane donated me some old upper arms from his D3 and the bushes were totally wrecked in those so 250,000km seems the limit.

[eddielines]

I’ve been chasing a thunk in front also and recently did tie rods. Next is upper arms have new bushes ready to go.

Interesting on LR Time yesterday same issue same diagnosis after doing tie rods.


My Tie Rods are good, I did have to change the drivers side a couple of years ago as boot split and was some play.

Some of the bushes are a pain, needs a special tool as not just a cylindrical end that press needs to work against. What are you using for these ?


Shane donated me some old upper arms from his D3 and the bushes were totally wrecked in those so 250,000km seems the limit.

Just over 200K and I replaced full suspension last year, all control arms and structs. Has done a bit of off road which will accelerate the demise.

Not sure why the bushes are shot on this after 18 months, it was torqued up at driving height, I am checking to see if covered by warranty.

[PerthDisco]

Once you cut them out (you can’t press out) pressing back in is not hard with a press using a variety of circular bits to push and support the object. Sockets and bits of pipe and old bearing shells are useful.

The upper arm bearings don’t protrude out the other side so you only need a nice ring to push on the flange end and lightly grease the inner surface of the control arm.

Photos taken so I can align new ones same same

https://uploads.tapatalk-cdn.com/20241118/c665aa7d6ebf099fd7a70c42f7eb9484.jpg

https://uploads.tapatalk-cdn.com/20241118/547d4c017e362c96e485ee40e5780919.jpg

New ones arrived today about $20-40 each ex USA. Shipping is cheap again ex USA for a box full of them.

https://uploads.tapatalk-cdn.com/20241118/d0af2218e9426bc7da73ab7fbf941e1b.jpg

https://uploads.tapatalk-cdn.com/20241118/a14e0a2c9c9b4b948ab4eba9b126f922.jpg

[Eric SDV6SE]

Made in Slovakia, sent to the us for you to order delivered to Oz. Wonder how they make any money on these, unless the manufacturing cost is in the order of cents per unit.

[PerthDisco]

Made in Slovakia, sent to the us for you to order delivered to Oz. Wonder how they make any money on these, unless the manufacturing cost is in the order of cents per unit.

https://uploads.tapatalk-cdn.com/20241118/e98c6b931ee7b30cf1e70d8e13c4b1f0.jpg

Yes United Nations must be mass market.

Can’t complain about prices

[Eric SDV6SE]

.

[eddielines]

Once you cut them out (you can’t press out) pressing back in is not hard with a press using a variety of circular bits to push and support the object. Sockets and bits of pipe and old bearing shells are useful.


New ones arrived today about $20-40 each ex USA. Shipping is cheap again ex USA for a box full of them.

https://uploads.tapatalk-cdn.com/20241118/d0af2218e9426bc7da73ab7fbf941e1b.jpg



When I did all arms last year I cut out and pressed the rear lower, but they had even cylindrical end. How / what do you use to press these with the rubber over the metal, if you use something that goes outside the rubber it may bend the metal back, if on top of the rubber it will damage it ?

Where in states did you order from ?

[PerthDisco]

When I did all arms last year I cut out and pressed the rear lower, but they had even cylindrical end. How / what do you use to press these with the rubber over the metal, if you use something that goes outside the rubber it may bend the metal back, if on top of the rubber it will damage it ?

Where in states did you order from ?

Rock Auto - it helps to know the part numbers as sometimes they are not covered when you drop down the car spec (V6 petrol only choice) is a quirk I discovered as I only want Lemforder but sometimes they list other brands but have the Lemforder when you part search it. Exactly what the upper arms did.

For these I’ll just press evenly on the top of the flange rubber with a thick wall ring. With a bit of grease and everything clean I’ve never had a fight pushing them in with a 30T hydraulic press.

I did the same previously with the LCA bushes which are much bigger.

[veebs]

Is the 'thunk' present for all models, or has it somehow reduced in the 8sp variants?

[eddielines]

Had car in to Indie last week for general inspection as planning trip to high country at easter. He said its common in the 6 speed with a bit of age, he drives same car, said mine was pretty minor, probably stretch in chain, so I'll live with in unless gets much worse.

[eddielines]

We did Monkey Gum out past Nowra a couple of weeks ago, if the drive line can get me through that, there can't be much wrong with it.