scobar

iTrader: (4)

Off topic, our trucks are 9.75" 34 spline, correct?

k.chaloux

Yeah it was all covered under warranty, I think they were dickin me around tho. said they replaced it every time but i think they were going the friction modifier route, and seeing if that worked. after a few choice words and friendly conversation, the problem was fixed the correct way with new clutch packs, ring and pinion, and input shaft bearing

zford05

What sort of upgrades can I make to the rear end? I have bad clutches in my rear end and after doing some searching online I have come across some aftermarket clutches/differentials that may be a whole lot better. One was an EATON brand diff which sounds awesome because it has carbon and steel plates rather than the crap that ford has to offer as a rebuild. Thoughts??

yoop

I consider myself a newbie as well, but i do the easy jobs on my own when it comes to fixing my truck. I changed my rear end fluid alone with the hardes part getting the cover to seperate from the housing. My 06 fx4 recomended a limited slip addiitive or a 75-140w gear oil with it already added, you can find it at any parts store. I believe mine was the mobil brand it runs about $20 a quart and you'll probably need about 3.5, take a look in your manual. very easy job and it may solve your problem also dont forget to buy a gasket and some permatex!

Turkey Hunter

If it just started doing it most the time changing the fluid will solve your problem. If its been doing it a while then sometimes its to late to sve it.

beantown617

Did changing the fluid help fix/make the problem go away? I just bought a 2005 f150 lariat w/the limited slip 100k mi. I get a vibration around 20-30 mph, worst around 27. Its samd vibration whether im cruising in gear or even if i drop in neutral at that speed. I dont think its any worst if im turning.

My dealer says they think my rear clutches are bad and quoting $1100. Im curious if (a) it really has anything to do with my differential, and (b) if so, would the fluid change fix it?

Thanks!

tcp2

sounds more like u-joints than the rear end. If this is happening in a straight line, it's definitely NOT the LS clutches. The clutches only do anything during a turn or if one wheel is spinning at a different speed than the other side. U-joints on their way out have a tendency to vibrate at certain speeds and then not so much at others. I would replace them in the driveshaft before giving ANYONE $1100 for anything. If you want to be somewhat pro-active, put a bottle of friction modifier into the rear differential. Cheap $8 maintenance. I have had great luck with redline's FM:




Or Ford's, PN: C8AZ-19B546A

beantown617

Thanks for the response tcp2. I actually noticed i have a little bit of play on my u-joint when accelerating from a stop (kind of a quick squeek at times). Didnt seem too bad yet though but now that you mention it that could make sense. I heard something about the 2005s have a PITA ujoint to service, something about them being staked to the yoke?

I figure its worth replacing regardless. Even if shudder is still there after replacing could try the LS friction modifier. Someone else also suggested checking parking brake to make sure isnt sticking. Worth a quick check.

Another thing they (dealer) said was that both my IWE vacuums in the front are shot and not holding vacuum, and that 4wd is always engaged. Said while at it to update IWE solenoid with the one that has the rain hat. I read thru a bunch of the stickys on this forum regarding the IWEs, and i dont seem to get the same symptoms as others - when my switch is not in 4wd i dont hear any clicking or grinding and get good gas mileage (~18.5mpg hwy on the 5.4 v8). But when i put it in 4wd drive, it drives real rough. Clicks/grinds when turning at times (not talking about jump from dead stop). I also dont really get the concept of if ur vacuums arent working to disengae the hubs, then it engages 4wd - does that mean everytime u turn off the truck and you stop running vacuum that it locks into 4wd? Is it possible to lose vacuum but not have ur hubs locked into 4wd?

Sorry i guess all that IWE stuff should prob be posted in another thread, but just figured id throw it out here too since dealer said "could also be potential cause for vibration"......

Thanks for the help!!

FANGS99

Scobar...... Yes, 5.4L trucks have 9.75 ring gear and 34 spline axles