[98GTstang]

Hey guys, I drive a 98 GT with a stock rear end except for 4.10 gears, which were installed about 2 1/2 years ago. Yesterday I noticed when I would turn going slow-medium speeds, I could hear and feel a clunking/grinding noise coming from the rear end. It seems to only happen when I turn and accelerate at the same time, can't hear it when turning and letting off the gas. Also, it doesnt seem to happen every single turn either, but it does sound very horrible. I checked the brakes, exhaust, and anything that could be loose back there..but I have a feeling its in the differential. I also checked the u-joints which were fine. Whats inside of the differential that could cause this noise?

Thanks for the help!

[KV007]

not good, u need to take the differential cover asap. check to see if theres anything seriously wrong and what do you have in the differential for fluid? i know my rear end would start to lock up when i put synthetics in it so i have to run regular with friction modifier

[98GTstang]

Its just got standard fluid with ford friction modifier..Just flushed it about 6 months ago.

[KV007]

hmm maybe your spider gears r going out

[skuzzy]

i heard something about mustangs have slack in the gears, but they way the sound is caused sounds wierd

[GOLDSTANG]

i need help guys don't know who to ask, got my gears installed but it makes this sound like if it was lose i checked everything and it looked fine checked if the gear ring was lose but its not what can i do how do measure and where do i get the tool to measure it i didn't measure because i couldn't find this tool its a 2000 v6 7.5 got 4.10 motive gears please help

[zdkel]

2.5 years and recently started making this noise???

If it were me, I would think back to when you drained the oil. So you drained it 6 months and then recently? Was shiny flecks or "milky' residue in the oil. It seems if the problem came about suddenly, something may have broken and hence the presence of metal in the oil.

With a dial gauge and plunger you could measure back lash. From memory (subject to error) the back lash in the rear gears is small, less than 0.008". You would check the back lash by measuring how much one gear moves before moving the mating gear. That's probably a poor explanation - if you search "how to measure backlash" on your favorite search engine, you should find some steps.

Hopefully some of that was helpful, Good Luck.

[GOLDSTANG]

dial gauge and plunger ok thank you very much do you know where i can get one i really need it got my differential opened right now and everything looks good but do you have an idea of how many rings go into each side i know its not the same on all cars but it might help or do you know anyone that did gears thank you once again

[zdkel]

Try calling some auto part stores, ask about there tool rental program - or some may sell such a thing. I have seen calipers (dial and digital) in home depot. The calipers can be used to measure small displacement 0.001", 0.002", etc you may have to get creative with your reference or 0.000" point.

[GOLDSTANG]

this thing is gonna make me crazy it has almost no back lash you can feel it just a little bit almost nothing checked for evrything to see if it was lose but everything ok what am i doing wrong and right now i dont have money to take it to a mechanic any help or advice

[fmxona500]

Sounds a lot like the spider gears or limited slip if you have one is going out. When you drained the oil, was there large chunks of metal in oil, or any metal in the oil for that matter? Did you fill the oil back up to the recommended level? Too much/too little and it can cause noise and wear.

Jack up one side of the rear end and spin that tire with the other one on the ground. Does it spin freely? Do you feel any thunks when you spin the tire by hand? Try to same on the other side.

I'd recommend not unbolting stuff from inside your differential if you don't know what you're doing in there. The rear end on your daily driver is not a place to start learning if you're not mechanically savoir.

[tfofkyle]

i suspect limited slip as well. the turning part especially makes me feel like something there could be at fault. my buddies 94 gt with a shot diffy makes similar noises to what you just described.

[GOLDSTANG]

no metal when drained oil it looked clean the tires spin with out making noise and if i lift one side at a time its hard to spin ill probably take it to a shop have them check my bearings might be that but car runs and feels great im about to order me a diablo tuner but ill go to a shop first make sure all its good

[fmxona500]

good idea