the diff covers are nice. but as fred said really over priced . the trans pan. well i have had some problems with it. and have returned to the stock pan, and purchased a new set of stock cat/pipes "ouch big time" . the modified pipe that we made to clear the new pan out of aluminized steel can't handle the heat from the cats, and burned though in 4 months. if thats done it must be a high grade stainless. and another small problem that we could not cure.
At this time i'm back to almost stock eccept for the super tune in the pcm and my 4:56's . no air intake . no trans pan, i do like my exhaust and am leaving that on. the 04 kit i used from flow master needed very little modifieing. mostly i had to make custom hangers and that was a peice of cake. the 05 hangers are in a different spot/shape then the 04's and a heavier rod size. i welded the correct size and shaped solid rod to like the stock ones to ss muffler clamps and held it up that way. and useing a straight peice of ss exhaust tube from the y pipe adapter end to the flow master 70. just as ford dose for the longer wheel bases as the fm is shorter then the ford muffler.
would i do it again NO WAY. i have played enough. there is more then enough power in a stock 3 valve. useing a tuner maybe to change the trans shifting points and frimness yes i would . spend almost a 1k note on the covers and pan no not again. not worth the coin or have any real true benifits . again i agree with fred clean the covers good and paint them up.works just as well.

 

In all the diff cover change-out articles I have found on the web, not one has given temp readings before and after the change-out. I know they claim 45 degrees drop, but I would sure like to see the tests on a real-world Super Duty to bear up that claim.

I had a 1985 E350 I towed with for 13 years and the diff never gave me a problem. I just put top quality gear oil in it. I have to wonder if that really is the secret. Mag Hytec recommends Lubrication Engineers gear oil with Amsol. We have been using LE products in our shops for years (30 plus) and have never had a diff failure on the old Spicer's in our F/L's.

 

mike i wish i had put in a dif gauge but have not ,in the trans i did note a drop to near 150 degs. with the pan while towing. but also noted a few other problems 1 being a 1500 dollar replacement set of cats . on a psd there is nothing in the way so it's just a up and down swap out.
useing what jerry at maghy-tec states to use sorry .i have my problems with those brands costing very high dollar failers of race motors
all the years i raced i towed both flat with a tow bar and on a trailer never had any problem with a diff going bad useing a stck cover and then all we had was 90 weight gear oil none of this new fancy stuff. even had it in our stick shift tranies .in cold weather if they shifted stiff we pulled out a pint and put atf in its place till sprting time.
do we need these fancy items ? sorry guys we don't .