8 speed RFE transmission..?

[TheEnder]

Hey everyone.

There’s a youtuber i’ve been watching for a while, he did a video a while back on adding an extra gear to a Jeep with the 45RFE (essentially turning it into a 545) with a new PCM.

Reading the comments, he said the RFE was capable of 8 forward gears, but no one has been able to program the TCM to take advantage of that so it isn’t possible at the moment.

Wouldn’t that physically be impossible..? What are some thoughts from everyone here on it?

 

[Wild one]

Hey everyone.

There’s a youtuber i’ve been watching for a while, he did a video a while back on adding an extra gear to a Jeep with the 45RFE (essentially turning it into a 545) with a new PCM.

Reading the comments, he said the RFE was capable of 8 forward gears, but no one has been able to program the TCM to take advantage of that so it isn’t possible at the moment.

Wouldn’t that physically be impossible..? What are some thoughts from everyone here on it?

I would think you'd have to activate both over drive planetaries on each gear change to come up with 8 gears,but it wouldn't give you a lower first gear,it'd just make each gear change really close in ratio's. You can turn a GM 4l80 4 speed into a 5 or 6 speed,by utililizing the overdrive planetary on each gear change. The downside to doing the same with the light duty RFE is the overdrive clutches,they're the known weak link,and utilizing them even more,is going to put that much more stress on them. It might sound like a good idea on paper,but it won't give you a lower first gear or a taller overdrive ratio,all it'd do is give you a tighter spread on the gear change,as you'd have 1st / 1st an over /1st and 2nd over etc.

 

[caulk04]

The point of that old information is that the trans is capable of engaging that many ratios with the mechanical components. The other ratios you could theoretically get would be unusable.