Annoying Jolt / Slam when accelerating

[Blackbeast95]

Hi everyone, I recently purchase a 2004 X5 4.4 this year and it had transmisson problems and we had the transmisson rebuilt already.

couple months after the rebuilt transmisson when accelerating or past the "kick down point" the car would jolt / slam i would have to be going around 30 or 40 MPH then press down the gas and it would happen ( not everytime but quite often) if i slowly acceletate the problem does not happen and drives just fine.
there is also no engine lights or sevice lights on.

I never scanned it recently but going to soon I've read many of posts it could be the Mass air flow sensor that could be causing this im wondering if it safe to unplug the sensor to go for a small drive and see if the problem happens what is your guys ideas? thanks

[g300d]

Yes it's ok to unplug the MAF and drive it a bit.

But I dont think that is the problem if I understand your situation correctly.

[4.8iS Le Mans_NZ]

Does it do it when positive throttle is applied, or when you're slightly feathering the throttle?
My 6-speed tranny 'flares' and slams sometimes during acceleration from low speed (i.e. 2nd or 3rd gear) and only on a feathering throttle (i.e. beginning to back off).

[upallnight]

Depends on what was rebuilt. Did they replace all the bushings in the valve body? Tested the solenoids and replaced any that didn't meet spec. Replace the clutch drums with improved clutch drums?

When they tore the trans apart did they find out why the trans needed to be rebuilt?

[bcredliner]

MAF is part of the air/fuel monitoring system. Will cause loss of power, rough idle, etc. Never had one that caused a "jolt". Does this jolt have a sound that goes with it?

I would take it to the shop that did the rebuild and have it diagnosed. Transmission symptoms can be deceiving, leave it to the experts. Doesn't it have a warranty?

[OrangeFurious]

FWIW, both my 4.4 and 4.8is have done this regularly in the time I've owned them. It's annoying as hell and occasionally feels like being rear-ended. I had the 4.4 pretty heavily investigated by an indie shop (Signature in Kirkland WA) and they couldn't find anything "wrong" with it. Adjusting my throttle technique eliminated the issue.

[upallnight]

Originally Posted by OrangeFurious

FWIW, both my 4.4 and 4.8is have done this regularly in the time I've owned them. It's annoying as hell and occasionally feels like being rear-ended. I had the 4.4 pretty heavily investigated by an indie shop (Signature in Kirkland WA) and they couldn't find anything "wrong" with it. Adjusting my throttle technique eliminated the issue.

I guess when BMW boast about their adaptive transmission, people just assume that the transmission will adapt to their driving style and not the other way where you need to adapt to the quirks of the transmission.

[Quicksilver]

Originally Posted by upallnight

I guess when BMW boast about their adaptive transmission, people just assume that the transmission will adapt to their driving style and not the other way where you need to adapt to the quirks of the transmission.

Regarding the OP's problem I agree with upallnight.
Just turn the key on to the position just before you start the engine
press the accelerator for 30 full seconds and that's it. It's not an
engine mount, or Transmission mount problem. Iv'e done this
every 6 months for the last ten years with success

[omodos]

Originally Posted by OrangeFurious

FWIW, both my 4.4 and 4.8is have done this regularly in the time I've owned them. It's annoying as hell and occasionally feels like being rear-ended. I had the 4.4 pretty heavily investigated by an indie shop (Signature in Kirkland WA) and they couldn't find anything "wrong" with it. Adjusting my throttle technique eliminated the issue.

My 3.0d does this too, not often but does it...and yes 1st time thought i was rear ended...

[o3x5e53]

Engine mount, Transmission mount.