Giant Driveline Lurch/Clunk When Shifting?

[RSchwarzli]

I hope this was not already discussed, but I have a VERY large clunk in my driveline when I shift from D to R or the other way around. Is this normal with the new 68RFE's? I gather it must be from torque load when shifting to a different direction, but it cannot be good for the diff either way!



Any thoughts? Anyone else have this?



Thanks!



Robert

 

[RSchwarzli]

Anyone? Am I the only one!?



Robert

 

[HBarlow]

Mine is a C&C with AISIN so a little different but I experience no driveline slack or clunks when shifting to R or D.



Is your engine at normal idle speed when you put it in gear?

 

[RSchwarzli]

Yes, it is at normal idle.



Robert

 

[Cattletrkr]

I get it too, but I have the Aisin same as Harvey. I don't like it, didn't know others don't do it. Might have to keep an eye on it.

 

[RSchwarzli]

I don't like it, didn't know others don't do it. Might have to keep an eye on it.

Thinking the same thing.....



Robert

 

[HBarlow]

I don't want you guys to spend a bunch of time worrying about your trucks or making useless trip to a dealer. Just because I don't recognize mine as a problem doesn't mean yours is malfunctioning.



Maybe we're discussing the same event with different tolerance for it.



Certainly all automatic transmissions grab firmly when the lever is moved from P to D or R but I don't feel an unacceptable jerk or hear a clunk.



Next time I drive mine I'll pay more attention to the shift and see if I'm ignoring the same symptom others are expressing concern about.

 

[Skyhigh]

Yes, mine also has somewhat of an aggressive engagement.



Is it overly aggressive? Nah not that bad. It is WAY more agrresive going into gear than my 06 5. 9 was.

 

[MSkajem]

I too have that distinctive clunk when shifting from D to R and R to D... I only have 600 miles on my truck and I had an 2005 before... I am thinking of taking it to the dealer because it seem so jerky and it certainly doesn't sound good either... . anyone have advice before I make the trek back to the dealer?

 

[RSchwarzli]

To me it sounds like a hard knock, as in something in the diff. Nothing else in the driveline should be able to produce such a low, hard sound.



As far as aggressive engagement, I do not see that as a issue. Look at the cars from the 60's. Those were VERY aggressive engagements. What I don't like is the metal on metal sound that goes along with it...



My 2 cents...



Robert

 

[HBarlow]

Update:



I drove my truck tonight. I hadn't started it since Saturday afternoon so I started it, allowed it to idle a minute or two, then shifted it into R. I deliberately rolled down the windows to listen. My truck won't fit in my side-entry garage so is parked under a low metal carport and only 18" from a tall wood fence. Combined, the garage door in front, carport overhead, and fence to my right should contain and reflect any abnormal sounds. The shift to R was not overly firm and I heard no clunk or other objectional sounds.



Later, I shut down and started the truck twice more with it at operating temperature and felt or heard no objectional jerks or clunks.



I even tried it while fast idling at 900 rpm. My Park/brake pedal interlock is disabled so at 900 rpm I simply grabbed the shifter and moved it to the R position. No brake application required. The ECM recognizes when the shifter moves from the P position and immediately disabled fast idle dropped idle speed to 700 rpm and when it went into R it loaded the torque convertor and drive train as expected but no abrupt jerk and no clunking sound was felt or heard.



Maybe some of them have slightly wider clearances between ring and pinion in the differential or other drive line slack.

 

[tom sweeney]

mine clunks at times,but not enough to warrant a visit to the Dealer... . it's just "the nature of the beast"... probably just a little driveline slap,at 13k+ i just returned from a weekend camping with fellow member Larry Willard,the truck performed fine... . even found fuel for $4. 59 per gal!!!... . thus far i'm very pleased with this vehicle,especially the 68RFE and exhaust brake function in the turbo housing... . i find myself using tow/haul mode even when "bob-tail" simply to take advantage of the extra braking power!... i REALLY love the reverse gearing being so low... . it makes backing-up the 5'er a breeze!!!

best of luck to you and your truck,maybe catch you on the road sometime

tom sweeney

 

[JohnHaggerty]

Got it Too!

I also have the "clunk" originally described in this post. #@$%!



I only have 1,000 miles, so I haven't got a handle yet what is actually happening. There is something wrong here. If there isn't something wrong, then this transmission is not going to last long.



I will better monitor what and when it happens to better understand what is actually happening. I will fix it, just have to figure out what it is.

 

[JLDanner]

Mine does the same thing - especially when going from drive to reverse and back again - or even when just changing from drive to park. Dealer claims its normal. It pretty da*$ loud - makes me cringe every time. The diff is bullet proof, but it still makes me cringe. Evindently the torque converter is pretty stiff.