Engine braking? and a “transmission clunk”

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dwinter
Vehicle: Pajero SWB 3.2DiD
Posts: 116
Joined: Mon Apr 05, 2010 9:41 pm

Engine braking? and a “transmission clunk”

Mon Apr 16, 2018 10:32 pm

Hi all,

Two questions for you:

What are your thoughts on using the tiptronic gearbox on a Gen 4 DID to gear down to assist with braking?

I’m not referring to the automatic gear down that the car sometimes does when descending.

This is something I do on occasion, particularly if on a long descent and I don’t feel like constantly hitting the brakes.

Any thoughts / issues doing this?

Second question - lately, on occasion I hear a clunk from beneath the car - I think it’s toward the rear of the vehicle. I was hearing it fairly frequently (2 x per urban commute), but less so lately. It happens when I pull away from a stop and I’m pretty sure it’s not brake related.

I do however wonder if it could be related to the engine braking technique I use.

There’s a longish (500m) and fairly steep hill that I go down in 3rd gear, and when I turn off this road, come to a stop at a stop street, most times when I pull away it clunks at this point. I’m likely clutching at straws, but wondered if perhaps the transmission is being placed under mechanical strain from the forced engine braking and then when I pull away again it releases with a clunking sound.

Hope all this makes sense.

Any thoughts / ideas appreciated.

Thanks, Dave





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Pajero 3.2 DID LWB GLX
Pajero 3.2 DiD SWB [SOLD]
User avatar
RoelfleRoux
Country: SA
Vehicle: 2008 3.8V6 LWB Pajero
Location: Barberton, Lowveld
Posts: 1676
Joined: Wed Jul 29, 2009 1:42 pm

Re: Engine braking? and a “transmission clunk”

Wed Apr 18, 2018 5:24 am

Dave,

My very first Pajero (1994 3.0 V6 manual) had that symptom, but only after a long drive. If I came off a highway, stopped and then pulled off it gave a once off clunk. Mine was (I think) off the front diff area. It never really bothered me.

As for gearing down manually, absolutely the correct thing to do. I personally never allow the engine to exceed 2500 rpm. I actually prefer 1500 - 2000 rpm. The gearbox doesn't do anything different from a mechanical perspective in manual. All you do is to make a suggestion to the gearbox computer of a gear selection you would like. The computer then considers your request and on approval will pass it on to the gearbox.

Manual gear changes up through the box is a slightly different scenario. The engine computer reduces the engine power before a gear is changed. In auto mode this reduction is longer and "lower". In manual mode the reduction is less and shorter. One can actually feel it if you know what to be on the lookout for and hence the term "Sport Mode". That said, the box is designed to operate like that and I never passed up on an opportunity to use it as such.



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User avatar
dwinter
Vehicle: Pajero SWB 3.2DiD
Posts: 116
Joined: Mon Apr 05, 2010 9:41 pm

Re: Engine braking? and a “transmission clunk”

Wed Apr 18, 2018 10:39 pm

Thanks for the response RoelfleRoux.

Ok - so I’ll continue to use the manual gear down method for certain braking. Must say, that’s one habit I miss from driving a manual, but nice to know I can still do it to an extent with the tiptronic box.

Clunk - it seems to have lessened in frequency, but will ignore for now.

Thanks again.


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Pajero 3.2 DID LWB GLX
Pajero 3.2 DiD SWB [SOLD]
vaughn
Country: South Africa
Vehicle: 2010 3.2DiD
Posts: 11
Joined: Mon Sep 17, 2012 7:08 am

Re: Engine braking? and a “transmission clunk”

Mon Apr 23, 2018 9:06 am

Hello all,

I use the engine braking all the time, saves the brakes on long down hills, as long as you keep the revs reasonable you won't have an issue . Regarding the clunk, On the last 3 Pajeros I've owned I noticed a "donk" sound when I slow down harshly with the gearbox or the brakes, and sometimes when I accelerate. I eventually discovered that it only happens with a full tank of fuel.Why I have no idea. Check it out, maybe you hit a luck.

regards

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