2nd to 3rd gear change thud/thump

Dear all,

I have a 2001 automatic td4 and need some help. The car drive and change gears very well when cold but when it reaches the normal operating temperature the gear change from 2nd to 3rd is accompanied by a thud/thump that seems to come from the rear of the car. I have observed it for some time now and I'm certain it does this only when the engine is hot and only when changing from 2nd to 3rd gear. I have so far changed the gearbox oil, diff oil, engine oil, transfer box oil but no joy. I have also checked the rear diff mounts and these are okay. I had it scanned for faults but nothing came up.
What else can I check? You suggestions are welcome.

Rear subframe cracked? Engine mount broken/loose?

Thanks for the reply.
I had a look at those as well but did not see anything odd. If it was any of those I guess the thud/thump would be there through all gear changes and also when cold.

Worn VCU mounts or rear diff mounts seem the likely culprits to me, how did you check them?

Cheers

Blippie

hi ya Blippie - dont see yu in here too often?

Been too busy out enjoying the three Landies!

My thousand posts can't compete with your thirty four thousand!

Cheers MHM

Blip

cen - I've a 2001 Td4 Automatic too. I had a what sounds like the same problem changing between 3rd and 4th at @ 30mph. Although it feels like the problem is coming from the back of the car, its the line pressure release solenoid (iirc) that is starting to fail. Do you get the same problem if you use the steptronic shift? and is it only between the same two gears?

Blippie and Herald thanks for your responses.
The rear diff front mount was removed from the car and found intact. The VCU support bearings were changed and are new.

Herald, yes I get the same problem if I use the steptronic shift and it is only between the same two gears. All the others are fine. Will a failing solenoid show a fault on the scanner? The scan does not show any fault with the gearbox.

It never showed a fault on mine. I'd take it to an automatic gearbox specialist for a diagnostic. I didn't get much joy from LR main dealer.

I didn't spot the bit where you said it was an auto... I haven't a clue about those box of tricks so await the answer with interest!

Cheers

Blippie

The thud seemed to come from the rear of car so to elimate the posibility of a faulty diff and anything else at the rear I decided to remove the entire propeller shaft with bearings. Took the car for a test drive & still felt the thud though this time it was not as pronounced as with the prop shaft on.
This means the problem is with the gearbox or IRD since no drive is transferred to the rear of the car. Removal of the prop shaft however has helped eliminate the knocking noises I used to get when reversing or moving forward slowly with steering turned in either direction. I will drive the car like that for the time being until I figure out what else to check.

It been a long time, but did you manage to solve this?

?I dount it - with 5 posts