I started having problems yesterday with my F150. Overdrive OFF light came on and would not turn off. From what I have read, that is Ford's way of letting you know that there is a transmission error code. Drove the truck home, but when I tried to move it this morning, definitely heard metal to metal grinding!

My question is, once I have the truck error code diagnosed, if the tranny needs a complete rebuild, is it better in the long run to buy an already rebuild 4R70W with a 3 year/36,000 mile warranty, or just rebuild the one I have.

The truck is not used for towing anything right now, but will be in the near future used to tow a boat.

So, better to rebuild, buy rebuilt or bite the bullet and buy a 4R100?

Thanks, Dave

 

Well, i wouldn't waste your time with a rebuild, especially if there was "metal to metal grinding". I'd get either a remanufactured unit, a Monster Box, or the 4r100.

 

Swapping in a 4r100 isn't as easy as it sounds. Get a well built 4r70w such as a monsterbox. Depending on location I know a few other people who build good units in the indianapolis or cincinnati area.
Alan

 

http://racetransmissions.com/store/p...roducts_id/272

 

Whart are the complications of swapping the 4r100? I know that the F250 light duty, and the F150 7700 come with them. A buddy of mine totalled his diesel truck, and I am gonna get the freshly rebuilt 4r100 from him, and buy a new torque converter. Towing 5700lbs, almost everyday tends to smoke the 4r70w pretty quick. Thanks for any info.....

 

The 4r70w can be built to handle that with the exception of overdrive.
Alan

 

That is also a problem. A lot of the time I spend towing is on the interstate. When I tow this amount of weight with the overdrive off at 70 mph i see about 6.5mpg. using overdrive I get about 8mpg. That is a significant amount when driving ~4000 miles/mo. I have the freshly rebuilt 4r100 ( less than 500 mi.) in hand. There was no cost involved, so it doesnt make sense to spend 3000+ on a 4r70w that is gonna get smoked anyhow.....Thanks for the info, but I need to know what is involved.

 

The computer that's in the truck now knows how to control a 4R70W. It doesn't know how to control a 4R100. You'll need a new computer.

You'll need to make an adaptor to bolt that trans up. The bolt pattern on a diesel is different from any other engine.

 

It would be easier to get a gas case. The 5.4 or v10 case will be just fine. You need to replace the wiring harness with one off a 5.4 vehicle and the engine computer. You need the correct driveshaft and crossmember. I am not sure about the shift linkage you may need that as well. You will also need to bend cooler lines or modify the ones on the 4r70w to work. Bending new ones would probably be easier. You need the correct flexplate for your engine as the 4r70w and 4r100 flexplates are not the same.
Alan

 

Awesom, I really appreciate it. It does sound like a bit of work, Gonna start hitting the junk yards for some stuff....thanks again.