having a little backlash noise with new 8.8

[ShortThrow50]

just installed a brand new ford racing fully assembled 8.8 axle assembly.finished the install last night and took the car for a spin after work. Man what a world of difference the 373's make over factory 308's. after letting my foot off the gas a few times i heard some clunking. So pull it in the gargae and raised the back end. with the car in neutral and the e-brake off, I gently rolled the tire on each side individual and there seems to be slight play roughly an inch or so going by the outside diameter of the tire before it catches the splines inside (im assuming). I can audibly hear it. Like an idiot trying to save money I through the old axles from the original 8.8 in the new one. The axles had 65k miles on them. I know they were original but never heard the clunking in the old setup. The old 8.8 was in ok condition but the trac lok was done and the oil in the rear was never changed from what i saw when i opened it up. Should the axles have any play before it catches inside? or is it supposed to be tight as can be?

 

[GearHd6]

I wouldnt think your old axles with just 65k on them would be causing you any issues. When you're spinning the tires are they both moving an equal amount or is just one side moving? You dont want to be mistaking spider gear movement for ring gear backlash.

 

[ShortThrow50]

I wouldnt think your old axles with just 65k on them would be causing you any issues. When you're spinning the tires are they both moving an equal amount or is just one side moving? You dont want to be mistaking spider gear movement for ring gear backlash.

thanks for the quick reply man. No, the tires will move individually with the freeplay.

 

[GearHd6]

Try leaving the rears on the ground and jack the front up, throw the tranny in neutral and see how much you can turn the driveshaft each direction. Thats a much better gauge of backlash.

 

[ShortThrow50]

k, just went out to do that. rotating the driveshaft how you explained to do it. I got 1/4 inch of freeplay. I also heard it hitting the pinion gear first before it hit the axle splines and i measured that to be about 2/8ths of an inch

 

[ShortThrow50]

also, i have a stupid question. with the new rear install, was i supposed to put gear oil in the axle tubes or it fills up when you fill it through the fill hole

 

[GearHd6]

Was the car level when you added the fluid through the fill plug in the front of the rearend? If the back was just jacked up then you could be a little low on fluid. The fluid makes its way into the axle tubes so you dont have to add any into the tubes.

For the 1/4" of driveshaft movement, I dont think thats overly excessive once you factor in the actual pinion backlash and a little play in the spider gears and axle splines. I say worst case you've got to pull the cover and look inside while you move the driveshaft so you can better see the backlash against the ring gear. Ford uses 1 piece carrier shims so I dont think those have worked out of place. Sounds like you should check Fords work by pulling the cover off to be totally sure.

 

[ShortThrow50]

how much fluid does it take. The car was pretty level. I used about 2 and a half quarts

 

[GearHd6]

how much fluid does it take. The car was pretty level. I used about 2 and a half quarts

Boy, I just pulled the axles on my car this summer and if I recall it took all of 2 quarts but I dont know the exact spec on it. I think I used all of 2 quarts plus the bottle of friction modifier so 2+ quarts.

 

[ShortThrow50]

Boy, I just pulled the axles on my car this summer and if I recall it took all of 3 quarts but I dont know the exact spec on it. I think I used all of 3 quarts plus the bottle of friction modifier so 3+ quarts.

thanks for all the responses bro. Ill go back out there tonight and tryputting more in. maybe it needed to settle in the tubes or something. Thanks.

 

[ShortThrow50]

also, one more thing. If i put the ebrake on and go between 1st and reverse to rock it back and forth under load. I get no clunk noise. only happens when i back on and off throttle while driving.

 

[GearHd6]

And it didnt do this at all with the other rearend or are you doing all these things trying to find something wrong with it? Everythings tight under there? Upper and lower control arms? Quad shocks? Wheels? Loose control arms can make very odd noises from very odd places. Make sure those control arm bolts are wound real tight.

 

[MikeC]

I had a clunk a few years ago after I installed 3.73 gears. I adjusted the backlash down to about nothing but I still had the clunk. I narrowed it down to the interface between the axle and the spider gears. The axles were used and did show some wear on the splines. After a while I just got used to the clunk, and learned to drive around it to where you could not hear it anymore.

 

[ShortThrow50]

huh. I guess I will chek all this stuff again.