Defender shaking at 40mph when under load

Hi guys, I have developed a fault over night with my defender 90 which has a disco 200tdi in, when I accelerate to around the 40mph mark, I get a terrible vibration, and is even worse when under load I.e. Going up hill, I have checked compression and 3 pots are at 410 but number 3 is only at 360 could this be the problem? I have a oil leak from my head gasket so am going to replace that at weekend anyway, any body have any ideas. I have checked the propshaft for play but there is very little. All axels have oil as well as gear/ transfer box. Any suggestions? Thanks

Mine has this, Mir is play in the input on the rear diff, could be seized prop uj

Didn't think of seized uj. I will check this too, any other ideas?

check u js and diff mate ,,or if u have been in mud check your wheels

Do you still get it if you drop the revs and put your foot on the clutch?

Funny thing, when I checked oil it was like water in rear diff, and over full as I took plug out it run out for a while before stoping, I changed all diff oils last year and deffo did not over fill, is it possible to get water in diff, I've not been off roading or wading at all!! What is best way of testing rear diff

phippsey27 said:

Funny thing, when I checked oil it was like water in rear diff, and over full as I took plug out it run out for a while before stoping, I changed all diff oils last year and deffo did not over fill, is it possible to get water in diff, I've not been off roading or wading at all!! What is best way of testing rear diff

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Short answer is yes, very possible but think unusual if not been through deep water

Not been through any deep water what so ever, oil was very thin and of greyish colour? Is there anyway of testing diffs ?

It's the prop shaft uj's.

Mine is the rear diff input has come loses again some how. It sometimes doesn't shake but under load its a massive shuddering / shaking dip te clutch and it goes away

Well thanks very much for all the advise. Seems it's not as bad as I thought lol. Will let you know how I get on. Once again thanks

Mine does this even with a new recon transfer box and 2 new wide angle props. Either me front diff or tyres need balancing as they've not been done.