Rear "whomp"!

Technical Advice, Faults and How-To Information.
nurgle
Posts: 50
Joined: Fri Aug 03, 2018 8:43 am

Post by nurgle »

My 2013 V6S has just over 60K miles and whilst under 2 yr extended warranty suffered a failed (full on crunching!) differential. This was replaced under warranty. It is now 6 months post warranty and the diff has only done about 8K miles.

The car has the following symptom:

After an overnight parked up, the car starts no problem. On reversing or driving forward, some mornings there is a 1 sec "whomp" from the rear that you can feel in the base of the seat. Sounds like it should be suspension (but is unrelated to road bumps). This "whomp" might happen a couple of times getting out onto the main road, usually with some turn on the steering wheel.

It is not constant on turning, nor worse with more lock.

It very rapidly reduces in volume after half mile or so, and after 10 mins is completely gone. Park up for an hr or so, drive off doesn't occur again.

Park up all day or overnight and the cycle repeats (the 'whomp' seemingly temp related).

I deliberately took the local Jag specialist tech out in the car after 30 mins driving and we agreed there was nothing at all to hear or sounded/ felt wrong. Next morning, took him out and getting out of the garage a couple of 'whomps' immediately then a few more as we drive around that surprised him greatly given the perfect running the day before!

Car drives perfectly.

Local independent Jag specialist reports (via voice message) the sound comes from the differential, discussing tomorrow in more detail!

Any ideas what might be causing the diff to make such a noise?

regards,

Rob
Last edited by nurgle on Thu Jan 09, 2020 8:05 pm, edited 1 time in total.

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scm
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Joined: Fri Aug 10, 2018 11:39 am
Location: Southampton, UK

Post by scm »

If it's not the diff it might be time to consider a gearbox fluid change - I seem to recall the older 6 speed ZFs doing a whoomp as the sign that the fluid was spent. ZF suggests a fluid change around 60k miles.
MY18 F-Type V8 R AWD in Glacier White
Lots of leather and toys, and loads of noise!
nurgle
Posts: 50
Joined: Fri Aug 03, 2018 8:43 am

Post by nurgle »

scm, thank you for the reply, I'll mention that to them
GARETH
Posts: 247
Joined: Fri Sep 21, 2018 10:43 am

Post by GARETH »

Mine does the same. It’s been doing it for ages. When the car was in warranty I did ask them to investigate it during 1st service. I was told that it was the limited slip differential and that it was normal. They said they had checked the oil in the diff and all was well.

Mine does it more when cold, but still can feel it at slow speed even when hot. My car is now on 34k miles and this has been around since first service. It’s not got any worse and to be honest I don’t notice it anymore.
2014 Jaguar F-Type 3.0 S Coupe in Salsa red
2021 Land Rover Defender 110 X-Dynamic HSE
1968 Land Rover Series 2a 88”
1966 Land Rover Series 2a 109” ex army.
nurgle
Posts: 50
Joined: Fri Aug 03, 2018 8:43 am

Post by nurgle »

Update: The diff oil is brown and gunky, which after only a few 1,000 miles is clearly abnormal.

In a car that otherwise sounds and drives perfectly after warming up, any thoughts on what in the drive line might be stressing/ breaking my diff?

I'm going to get the gearbox serviced (new filter and fluid) which could potentially be part of the problem (at least excludes it and is due anyway!)

Rob
GARETH
Posts: 247
Joined: Fri Sep 21, 2018 10:43 am

Post by GARETH »

Let me know how you go with this. Is yours the 8 speed auto? If so how are you going to change the oil? I have a Discovery 4 with the same box, on 110k miles and it needed a dialysis machine to do it, as most of the oil is in the torque converter and cooler including its pipes. It also uses a special ZF oil which is not cheap!

It may be easier on the Jag, but the D4 is an expensive job.
2014 Jaguar F-Type 3.0 S Coupe in Salsa red
2021 Land Rover Defender 110 X-Dynamic HSE
1968 Land Rover Series 2a 88”
1966 Land Rover Series 2a 109” ex army.
nurgle
Posts: 50
Joined: Fri Aug 03, 2018 8:43 am

Post by nurgle »

ZF 6 speed in my MY car. The local Jag independent will do it for £395 all in
GARETH
Posts: 247
Joined: Fri Sep 21, 2018 10:43 am

Post by GARETH »

Is yours a manual transmission?
2014 Jaguar F-Type 3.0 S Coupe in Salsa red
2021 Land Rover Defender 110 X-Dynamic HSE
1968 Land Rover Series 2a 88”
1966 Land Rover Series 2a 109” ex army.
Deleted User 1715

Post by Deleted User 1715 »

GARETH wrote: Fri Jan 10, 2020 6:15 pm Is yours a manual transmission?
2013 V6S so must be 8 speed auto?
nurgle
Posts: 50
Joined: Fri Aug 03, 2018 8:43 am

Post by nurgle »

Yes, 8 speed auto!
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