shazoo

hi there,

i have 2008 Q7 3.0 TDI with CASA engine and KMB tranny.25 K miles on clock.The problem is when i shifting my lever from P to R car take sometime strong jolt some time its minor next time even no jolt but rest of gates are fine and no more problem once you are on the road.some times engine is dead when we are in R gate.i allready check the tranny oil level its fine.and there is no technical information about this issue nor any updates for tranny control unit.what else i suppose to check?

shazoo

RenatoS4

Do you use the parking brake? If not it could just be the weight of the vehicle imposing itself on the tranny when not parked on a level surface. I notice this as well on my '09 Q7 TDI.

adriangroom

Same on my 2010 3.0TDi... and it's as RenatoS4 says.

Noticed it a lot when first got vehicle. Easy to overcome if it's a parking (set-off) issue... just put it in N while holding on foot brake, put on park brake, release foot brake so the vehicle weight is taken on the park brake then shift to P.

As the weight's now on the park brake and not the gearbox there's no jolting, clunking or stiffness when you then shift through R... simples!

What do you mean when you say sometimes engine's dead when you are in R gate? do you mean there's no pick up between the engine and gearbox?

If so... just try wiggling the lever back and forth in the gate and you might find it engages... this is a problem on some of the electronically controlled VAG selectors.

arU4ic

What is a CASA engine and a KMB transmission?

shazoo

thanx for your Quick response.no i never use foot brake when shifting from P to R.yes as i told about engine off when u put lever in R and hold the brake pedal for five to 10 second and also i note when steering wheel is fully turn either left o right side then engine off but this happened seldom not allways.any suggestion apprecieted.

Arrie

How are you even able to shift from P to R without applying brakes? In my Q7 this is not even possible as there is a shift lock that does not allow moving from P without applying brakes.

Arrie

adriangroom

What do you mean when you say about the engine sometimes being 'dead' when you are i R gate and 'off' when on full left/right steering lock?

Do you mean it stalls, or just that there's no transmission of power between the engine and gearbox/drive shafts?

shazoo

first sorry for my english and yes this word is correct engine is stalled want to share one more thing that this engine having low comperation pressure say 17:1 bar average in each cylender does this could be a cause for engine stall?

Jusforfun

No! compression of 17:1 is not stalling your engine. That is standard for Q7. The injector pressure is about 29000 PSI. Remember this engine is turbo charged so it is not compressing normal air pressure. It is standard for turbo engines to have lower compression than non turbo.

Pulling on your steering wheel at full lock is straining the power steering and could contribute to stall. Solution do not hang on the steering wheel just relax and hold with no strain or ease back a tiny amount.

Q7 is designed to only allow shift from Park to Reverse while the foot brake is being pressed. Doing it any other way is incorrect and will cause damage to to some component.
If you park on a slope or hill, use the parking brake before you stop the engine as you park then the transmission is not under a strain or load when you start up later. You should engage reverse (with your foot on the foot brake) before you release the parking brake so there is no load transferred to transmission. In Park The Q7 will lock two gears together with the output side of the transmission to prevent rolling or movement. That is why it is difficult to shift when there is a slope and no parking brake used.