Hi guys, I have a 2005 F-150 I lowered 2" in the front and 4" in the back. I lowered the truck with 2" coils in front, shackles and leafs in rear and all new shocks. About 45k miles later, (100k on the truck total) the planet bearing? (I think) went out in the transmission and I had the whole thing rebuilt and added a reprogrammer kit. One month later, the pinion bearing in the rear end went out and again, had the whole rear end gone thru and rebuilt. 20k miles later, I bought a 21' 4000lb ski boat I started towing around a few weeks ago. I now need another transmission...both times the rear seal has leaked. Am I destroying these transmissions with the lowering kit? I have taken it in to Les Schwab where they lower trucks all day long and the said no way is my drive line wearing these things out. Is this just a fluke? Anyone have any clues or suggestions. I am strongly considering removing the whole lowering kit. Thank you!

 

No problems here and I've had the drop for years and many thousands of miles.

 

It's a fluke I expect but to make sure .... with the truck on ramps so you can get under there or with it over a grease pit maybe, get under there and look at the front slip yoke where it goes into transmission and check to see that it has travel. I'ld unfasten the rear U-joint flage and move the shaft forwards until I felt resistance and that's how much travel you have .... now with driveshaft attached back at rear flange, have some friends, one at a time, pile into bed and you underneath and make sure that when suspension is compressed .... that the front slip joint is not pushed in to the limit.

Only way that lowering will / can mess up a trans seal or rear sleeve / bushing or mess up a pinion bearing in the rear axle is if the slip joint is bottomed in the transmission and applying constant pressure against the bushing / seal at the trans, or bottomed on the output shaft (tail shaft) ... then it would put extra thrust force on internal transmission bearings and that front pinion bearing in the rear axle.

If you have a two piece rear driveshaft with a carrier bearing, when lowering real low they often move the the carrier bearing a bit to maintain an angle to keep the U-joints working the rollers at an angle some and to not straighten out the two shafts (which is longer than two shafts with angle).

 

Thanks for the feedback! Good tip on testing the slip yoke. As impulsive as I am, I just ended up removing the lowering kit and swapping over to a DJM flip kit with belltech shocks and belltech front struts set a 2" drop. I took it to a frame shop and they set the pinion angle for me. All I know how to do is wrench, not measure. I can't say I like the ride more. It is more comfortable but feels looser and defintely doesn't corner as well. NBow I can't tow my boat because the eibach springs barely flexed with weight but the OEM are soft. Now just trying to figure out how to get an air bag helper kit back there.