let me start from the beginning-
i had FRPP 4.10 gears installed last year along with new timken bearings, new seals and Royal purple fluid and modifier. i have about 6-8,000 miles on this . several months ago i noticed vibration and a loose or slack feeling when running about 60-70 and letting off. no noise any other time or vibration. two weeks ago i had another mechanic look at the car. on jackstands, there was about a inch of play in the driveshaft. he said something is not right in the rear end. i take the car back to the person who originally done the gears, he says the same. i go ahead and order a new FRPP trak-lok to have on hand for when he opens the diff up. (several people said that they expected it to be the spider gears). after taking the cover off, he says the ring and pinion are perfect along with the backlash. no metal shavings and he said the factory trak-lok had about 40 thousands of wear. not hurt, just normal. i told him to go ahead and put the new trak-lok in so i wouldnt have to worry about it down the road. i drive the car home and during the same cruising speed as before, the vibration is alot worse ( 60-70, letting off ). ford 80/90 fluid was used along with ford friction modifer.
what could be the problem here? i cant keep paying to have the rear end fixed ( this is the third time, the first guy who tried to set up some 3.90s did not set them up right at all ). its very annoying and i didnt think it should be this complicated. please help
i had FRPP 4.10 gears installed last year along with new timken bearings, new seals and Royal purple fluid and modifier. i have about 6-8,000 miles on this . several months ago i noticed vibration and a loose or slack feeling when running about 60-70 and letting off. no noise any other time or vibration. two weeks ago i had another mechanic look at the car. on jackstands, there was about a inch of play in the driveshaft. he said something is not right in the rear end. i take the car back to the person who originally done the gears, he says the same. i go ahead and order a new FRPP trak-lok to have on hand for when he opens the diff up. (several people said that they expected it to be the spider gears). after taking the cover off, he says the ring and pinion are perfect along with the backlash. no metal shavings and he said the factory trak-lok had about 40 thousands of wear. not hurt, just normal. i told him to go ahead and put the new trak-lok in so i wouldnt have to worry about it down the road. i drive the car home and during the same cruising speed as before, the vibration is alot worse ( 60-70, letting off ). ford 80/90 fluid was used along with ford friction modifer.
what could be the problem here? i cant keep paying to have the rear end fixed ( this is the third time, the first guy who tried to set up some 3.90s did not set them up right at all ). its very annoying and i didnt think it should be this complicated. please help
