Hi Everyone,

I have a 2003 G35 sedan and this months problem is that I am being told there is an issue with the Ujoints or drive shaft. When I drive it, there is a very pronounced vibration that at first I thought was a flat tire. It's like a rotational vibration and a local mechanic drove it and says it feels and sounds like the drive shaft or Ujoints. Does anyone here know what specifically should be looked at and a best and worse case scenario? I have limited funds right now and just put $500 in this car last month for a different issue. Thanks in advance.

 

I drive an X and had a serious problem with my front drive shaft ujoint failing. It didn't even vibrate but just caused clicking and bird chirpy noises. My ujoint was so bad it looked like it could have failed at any minute and I drove on it for a couple of weeks not knowing what it was. You can check for a bad u joint by trying to move the drive shaft up/down side to side at the u joint. If you joint is bad enough it will have some slop that you can feel or maybe even see the damaged parts if it's bad enough. do a search for front drive shaft u joint and you'll get a few links with pictures of what bad u joints look like.

I don't know how to determine if the drive shaft is just out of balance.

I'd rotate my tires first just because it's easy and we should do it more often than most people do and the nature of the vibration may change indicating it's a wheel balance problem rather than a drive shaft. Look for missing wheel weights maybe?

 

The best way to check for worn U-joints is to get the car up on jackstands or a lift and physically grab the yoke with both hands and pull it up and down and feel for play, rotate the shaft 90 degrees and do it again. Note the motion is not in/out (towards the transmission) but instead perpendicular to the propeller shaft itself. Rinse/repeat for all 3 U-joints in both halves of the propeller shaft. A worn U-joint usually has a very tactile "clunk" or "tick" and if it's REALLY bad you will simply feel the play.

I suspect you will find the worn component however is actually the CARRIER BEARING between the two propeller shaft halves, same "grab and pull" method as the u-joints but you can't rotate the assembly, just push and pull from 90 degrees out which is difficult.

If you can turn your own wrenches you can replace the joints yourself for probably $25, center bearing probably $50. It does require a press for the center bearing, if you don't have one you can typically just remove the components you need pressed and take it in to someone who will press the stuff for $50-$100 depending on whether you need all 3 u-joints or just the center, or whatever.

Removal of the propeller shaft and center bearing are VERY easy, it's literally 14 easily accessible bolts to just remove everything, torque is 70 or 54 ft/lbs for the propeller shaft flanges, 33 ft/lbs for the center bearing carrier, 83 INCH/lbs for the safety bar (floor reinforce).

Use match marks on the flanges and transmission output yoke, be careful with the slip yoke, there is a seal inside that you don't want to damage when reinstalling so just line it up straight and push it in nice and slow, don't force it. If you forget the match marks it's not the end of the world, I'm just OCD for things like that...

Section PR (propeller shaft) of the FSM.

http://www.nicoclub.com/archives/inf...e-manuals.html

 

I had a problem with my front driveshaft on my 2006 G35x. Didn't really end well when it fell off.


Front driveshaft universals are definitely something all X owners should plan on keeping tabs on at higher miles.

 

There's a ton of parts that folks should consider replacing BEFORE they exhibit signs of wear. Basically all suspension, driveshaft wearables, all bushings, common failure sensors that can potentially disable the vehicle like crank/cam position, timing chain tensioner, fuel pump, and any remaining OEM injectors and coil packs should be replaced at 150k if they haven't already. All those components have reached the end of their life by that time.

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After reading about front driveshafts failing I'm going to make a driveshaft loop while I'm rebuilding the drive train in the garage. I had a rear driveshaft in our jeep go out of balance from the U joint starting to fail, the side mirrors would vibrate really bad until we changed it.

 

Cleric i sent you a private message on another subject but i would like to know what you recommend regarding injectors and coil packs. I just ordered OEM crank and cam sensors from Infiniti Parts Do you also recommend buying OEM injectors and coils? My 08 G35 has 265K with the original sensors coils and injectors. Thank you very much for your help. Sincerely Larry

 

In practice I usually just go with the OEM manufacturer for those items, injectors I'm a bit more loose on though since there are a lot of good name-brand options. I typically avoid remanufactured injectors though and if I do use them I make damned sure to flow test them first (helps if you own a flow test machine, make friends with someone who has one if you can't afford the $500 to buy one yourself). Hitachi was the OEM manufacturer for coil packs so that's sort of a no-brainer since they are very reasonably priced.

However I only replace coil packs when they fail, I have NEVER replaced coil packs as a wear item but I do keep a spare in my trunk since it takes about 60 seconds to replace one on the side of the road. I also keep a spare spark plug because but in all my years of driving I've never had to do a highway emergency spark plug repair on a fuel injected engine since you can usually limp home, mostly just an old habit from the carbureted days when I used to carry all 8 in the trunk.

Fuel injectors is a little different, there's a LOT of good brands and they definitely can get changed as a wear item, personally I don't run more than 150k on injectors since they're at LEAST 10% reduced flow at that point. I pulled and tested mine at 100k I think and they were flowing perfectly though, right now I think I have 130k? on my car (it's over at the shop not at my house so I don't know for sure, it's winter and I don't really drive it much plus I'm doing Stuff™ to it). I plan on replacing my injectors next year probably, usually I just get Bosch for stock-ish power level type of application plus I'm almost certain they were the OEM manufacturer of injectors for all VQ35DE motors. You would need to do a little research to see what the OEM manufacturer was for your HR engine but I suspect it's still Hitachi for all sensors and Bosch for injectors.

Also, be sure to SAVE those old cam/crank sensors and throw them in your trunk, there's plenty of room under all those plastic dividers for the tire jack/wrench and it's a great place to keep spare parts like a coil pack, spark plug, keep your old belts when you replace so you have spares in the trunk, sensors, a roll of electrical tape, and a cheapo set of sockets, those little pop up roadside hazard flags, a flashlight and spare batteries, and a Haynes manual, all wrapped up in a large garbage bag to keep everything from rattling around making noise. Then if something ever DOES fail on the side of the road at least you have the option of fixing it on the spot rather than soliciting a flat bed hauler to bring you home. Whole package weighs like 10 lbs and there is PLENTY of room under those plastic trunk spacers to put everything on the right side of the trunk. Left side has electronic stuff so I wouldn't put it there.