Transmission issue

[ajgregory3tr]

Vehicle is X5 E53 3.0d 2005 facelift. When turning right and under hard acceleration to join traffic I experience a hard thump from the transmission. I don't get this when travelling straight. Any ideas of the issue would be welcomed. Recent work included new front tyres of the correct rolling radius, fluid changes to autobox and transfer box. This did not make a difference to the issue which appears to be more prominent when the car is cold.

[wpoll]

Were the oil wear adaptations reset when the transfer case oil was changed? It's a good idea to do so...

But your issue sounds more related to a differential problem than the transmission or transfer case. Any diff servicing done? What distance has the car travelled?

[ajgregory3tr]

Thanks Wayne, unsure re the reset I will check with Garage. I should have made it clear that the thump only occurs when setting off. When turning right whilst underway or rolling there is no issue, even when accelerating around the corner or when going around a tight right hand bend - hence my initially discounting diff issues.

[ajgregory3tr]

Mileage is 132k and no - not had diff service but driveshafts were checked and new boots fitted.

[EODguy]

Does it sound/feel like that u-joint slam you'd get from old Chevy or Fords?

If so it is possibly that computer controlled synchronizer in the transfer case. A reset of the system is necessary along with possible replacement of that little (motor?).

I'm sure I mangled the description but I had to have it done on my 2005 4.4i although my 05 4.8iS which is driven like I stole it hasn't had that issue so far.... Thank God.



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[andrewwynn]

Sounds like subframe bushing to me. Just one thump? If you can repeat every time you start that particular way it's slack somewhere.

Tip up your rear seat and if necessary remove one of the plates over the gas tank and all the drive train and suspension sounds will be literally 10x as loud and much easier to tell what is going on: don't freak when you hear all the different slack work through the drivetrain when you shift gears from forward to reverse etc

[Gregory891]

If thump on a right turn (if the noise is more up front) is more likely that RF driveshaft or (less likely) the front differential. Changing differential fluid (Redline GL-5 for differentials) is a good idea regardless - but not likely your problem.

IF you are rather convinced that it's transmission (or that area) - I'd look at the driveshafts and flex discs (you didn't mention if your car is a manual or automatic).

IF the noise is more from the rear, it could be the rear subframe bushings - although the clunk noise / feeling (I've had this) is more likely over speed bumps, pot holes. This IS an E53 wear item - I replaced mine ~3 years ago (approx 280.000 km) and it eliminated the bump / slam feeling over certain bumps.

Front types of the correct radius - could you be more specific of the size of the rubber as well as the wheel? Larger (i.e. wider) wheels tend to bring out the worst in cars - when there is something less than perfect.

Front axles - rubber replaced? Why? If the RF axle had a boot issue and suffered internal wear - cleaning the CV joint, new CV grease & boot have covered the immediate issue but possibly not the damage / pitting / wear to the balls and/or cage. My car had this (previous owner), it was cleaned and resealed - fix did resolve the issue for 100.000 km but I had specific noise on RH turns. A replacement (genuine OEM GKN) axle resolved the issue.

[ajgregory3tr]

Thanks for all replies, to my mind it seems to be coming from the rear. I am taking it into my local Indie to have the bushes and the drive shafts checked.

[ajgregory3tr]

Forgot to answer the question re tyres. Front are 255/50/19, rear 285/45/19. The reason for replacing driveshaft boot was a split, so clean, regrease and new boot was fitted by supplying dealer. They said wear was checked for but ...? I will have that checked when it goes in and have the diff oil changed as well.

[Rockabilly Rebel]

When you did the fluid change for the transmission, did you use an OEM quality filter? And fluid?

And, maybe more importantly, when filling with fluid:
Did you fill until it was dripping out, cap it, run it through all of its gears, re-open and re-fill until it was dripping out again?

If not, your fluid is too low and it will knock when you turn and push it. The correct amount is something like 6 quarts of ATF.