4R70W Failed

[sailsmen]

The first one failed @15K miles and this one had only 38K miles on it. It is in my wife's E150, no cargo hauling and no trailer towing. :mad2:

[drobin]

Maybe she thinks she's driving the Marauder.

drobin
"Donald"

[woaface]

Ever have that thing bettered in strength in any way since your mods???

[jspradii]

Ever have that thing bettered in strength in any way since your mods???
This tranmission should not be driven in overdrive execpt for highway cruising. The stock setup is known for failure under normal weight load and "spirited" driving, of any kind, in overdrive. Even with my built "J-Modded" unit, I only engage ovedrive when I'm going to be driving at highway sppeds for a while. The overedrive belt will not hold up in extreme "urban" driving for long periods. It's a fault with the design, and can be avoided by recognizing that any overdriving at under 2000rpm for an extended period of time is going to result in failure.

Jim:banana2:

[FordNut]

Strange so many people comment about the design flaws and weakness of the 4R70W and its use in vans. My 2002 company van has 101,000 miles of hard use with no special care. Put it in drive and go, romp on it from cruise in overdrive, all the supposedly bad things you can do to one, and it still works fine. Had the fluid changed at about 60k, it was fine. About time to change it again.

[jspradii]

I must say, thet when I had my 2003 300A tranny dropped to be built (along with my motor), it had not failed at 42K. However, the overdrive band was shot, and there was wear on the inner gears (direct clutch). I had, maybe, another 5k or so on mine before it had to be replaced. Normal use (even in a van: I had an '89 conversion van that had 160k on it before it needed tranny work) it should last. On a car where people abuse it or drive in overdrive in city situations, with the standard shift pattern, the tranny will not last. If you like the comfort of the stock shift, but still like to get on it, be aware that you will be in the transmission shop between 40-55k. If you tighten the shifts (less comfortable but more firm) the tranny ought to be good for a 100k before rebuild is required. If you want to race it, expect to put $1,200 or more in it to get it to the J-mod spec for 750+ hp. This is not your grandad's transmission, folks, it will break your neck shifting, but it will last forever (or almost!). My philosophy: If you want a lincoln buy a lincoln; if you can't, buy a grand marquis.