I have a '99 4.6 V8 with a 4R100 Automatic 4-Speed Transmission and it works just great. But, with almost 23,000 miles on it, I am wondering what I might do to make it live longer and shift better?!!

We use to put a "ShiftGO Kit" in the older transmissions that would make them shift more positively and thereby last longer. Or at least that was the claim. The idea being that if it slips for longer, smoother shifts, it is actually wearing faster. Quick, positive shifts mean less slippage and less wear. Does that still apply to these new Ford transmissions? Do you believe in a mechanical "ShiftGO" kit? Or is all that done by tuning the computer chip now days?

And how about changing my oil and filter in the transmission? AMSOIL has a synthetic transmission oil that is suppose to be the best oil you can buy. It's about $86 for a transmission oil change plus filters. I wondered what you guys think about that? Is it a waste of money ... or the smartest thing you can do?!! It will take someone smarter than me to answer that question.

My book says the factory put a good grade of synthetic lube in the rear-end but not in the transmission? Anybody know why?
Ford recommends ONLY Motorcraft MERCON ATF.

The Scheduled Maintenance Guide says to change the transmission fluid at 30,000 miles. So, I would like have my plan of attack all ready to go at that point in time.

Thanks in advance for any help you can provide.

 

As you have already proven you know, factory transmissions slip from gear ot gear for the drivers comfort causing it to wear out faster. And it does still apply to the newer trannies.

For these newer trannies you can do this one of two ways. First is to use a valve body shift kit like a TransGo, B&M, or Level10. Second option is a chip, a chip helps by electronicly incresing the line pressure in the transmission thus giving a much firmer and harder shift and not to mention the chip increses your horsepower too

 

Transgo Shift kit
bauman valves
Synthetic fluid

 

Bill,

Before buying anything for your transmission, make sure which transmission you have. I've never heard of a 4R100 mated to a 4.6L.

On the blue tag on the door frame of the driver's door there is a code letter for TRANS. An "E" means 4R100, while a "U" means 4R70W.

Mark

 

MArk is correct, there is no 4R100/4.6 combination, the 4.6 only gets the 4R70w.

G

 

I did the TransGo Shift Kit, the Super Chips and synthetic fluid. Still going strong with 47,000 miles on it. The shift kit has been in for about 27,000 miles.