[Nightdrv]

I expect this to go badly, but I bought it this way. So, whatever. Above approx 60% throttle, the car will not hold.. By this I mean that it "bucks", very angrily. Below that, it's fine. Shifts fine, sounds fine. It does have a humming noise when you're coasting on a flat, but quiet under power or load, or even off throttle going down hill.

So, what do you guys think?

 

[compu_85]

How many miles? Has the fluid ever been changed?

Doing a fluid & filter change is always a good first step. I've done 4 changes on ours since we got it to try and flush out all the accumulated crap.

-J

 

[Yeti]

Check the drive shaft center bearing too.

 

[noobytoogy]

x2 on the centre bearing.

As far as the "bucking" is concerned, is that definitely a transmission issue or an engine issue such as limited fuel flow due to a dirty fuel filter for example?

 

[Nightdrv]

My dealership has a $250 drivetrain fluid change service that I can use, but I'd have to bring in my own fluid, assuming VW has specified to only use theirs (I work at a GM dealer). For this price, they'll drain and fill all 3 diffs. Then a Trans fluid flush is about $190. Worth it? Maybe.

The "bucking" is pretty severe. Especially at highway speeds. Accelerate just a little, no problem. Push the pedal more than 50%, it just bucks really bad and tries to move. Do this long enough, and it'll start bucking at low throttle too, but only for a few seconds, before returning to normal. Funny though, every now and then, it'll catch a gear while downshifting, and pick up just fine. It'll go strong for maybe 7-8 seconds, before the bucking starts. So it's not alway the same every time.

 

[Nightdrv]

128k miles

 

[compu_85]

It's an Aisin transmission, so there are lots of fluids available. I used Castrol TransMax import last time in the transmission. I stuck with the factory fluid for the transfer case.

-J

 

[Blownvette]

Sounds like a driveshaft bushing. Go under the truck and grab the driveshaft near the carrier. If it moves left right or up down then that may be what you are describing.

The trans flush should be done by someone who has experience with the procedure. There is a instruction posted in the forum that will show what needs to be done.

 

[Nightdrv]

Well, I raised it all the way up and crawled under. Now, with it in Park, and on mostly level surface, all I could get it to do was make the front prop shaft move forward and backward. Neither the front or the rear would move otherwise. Would it have to be in Neutral?

 

[TREGinginCO]

The bucking sounds more
Like a fuel system issue ---- fuel pump, fuel filters ------ especially because you say the TRANS works normally otherwise.

 

[4ePikanini]

Change the fuel filter

 

[Nightdrv]

Just ordered one today

 

[V10DeezulDub]

When I was ordering my tune from Malone tuning the guy suggested I get the transmission tune as well. Saying if I didn't and the engine threw down more horsepower and torque than the transmission was programmed for it would cause severe jerkiness kind of like what you're describing with the only 60% throttle. Might be worth looking into. The guys I talked to were from AARodriguez ( www.fixmyvw.com) Just a suggestion do what you want with it. Sidenote I didn't do the transmission tune I just went with the stage one tune that Malone offered for the engine and I have been just fine

 

[Nightdrv]

Update: The bucking and jerking is actually due to cylinder #6 misfiring. That will be fixed hopefully with a simple but inexplicably expensive glow plug change. Then, it'll go back to the tranny shop again to have the trans rediagnosed.

 

[TUNINGBYAMG]

uh oh, this doesn't sound good. Glow plugs are only used at startup and do not cure misfiring in any way. If you have misfiring in this engine,the plasma coating is going, and probably not only in 1 cylinder...

 

[Nightdrv]

Just a follow up.. I know, very very old thread. ?

Anyway, it was in fact all of the above. The center driveshaft bearing went, but only because of the severe bucking.. which was caused by what VW labeled as "unrecognizable debris in the fuel system"... it was their joke to me that whoever owned it before me had probably never changed out the filters, or the pump, or the lines. They said it took them three tries to flush everything out of it!

Now she runs beautifully.

 

[FSJ Guy]

Glad you got it sorted out. Hopefully it wasn't too painful in the wallet.

 

[Nightdrv]

Glad you got it sorted out. Hopefully it wasn't too painful in the wallet.

Altogether about $2100 with everything from both shops.