Hi y'all,
I've been looking all over and getting mixed info. Some say a '99 tranny won't take any other year engine. Others are saying it will fit up to an '04. One post says a salvage yard will say it can't be done, sure enough, that's what my local one said. The post also said they swapped an '04 into a '99.
I have a dead '99 ext cab 4x4 with everything, and an '04 work truck- same engines (5.4L 2V). Can I drop the '04 into my '99?
Thanks

 

Not entirely positive, but I was under the impression all modular 8's and 10's shared bell housing bolt patterns.
My '06 V10 short block (from a 3V engine at that....) bolted right up to the original 4R100in my very early build '99 V10.
Perhaps they were referring to some electronic compatiblility issues?
To maintain compatibility with the '99 transmission and wiring, I used my original '99 PCM and all the sensors, TB, coils, FI's, connectors, etc

 

Wow, seems like an '04 would have to fit then since the '06 change to a 3V and still fit. The dealerships around here don't seem to know the answer, which is very scary.

 

In '04 the 5.4 still had the 4r100 trans. In '05 Ford switched the 5.4 to the 5r110. The '04 should fit the '99.

A diesel 4r100 will not work with a gas engine truck. And vise versa.

 

Thanks for the input. I agree with you. From everything I've seen and researched, it seems it should match up.
I don't know why the "professional" opinion is that '99 is all by itself for compatibility.
Unless Ford did some freak 1-off thing in the casting, which wouldn't make financial sense... I mean, it's not like they're GM!