transmission revving high w. brake controller

[az-streamer]

friends -

hope this is the right forum [otherwise in TV section? ]

anyway, the details are as follows:

TV is '09 f-150 supercrew 2wd w/tow package, tow/haul option etc
AS is 22' ccd model

brake controller is from primus, installed by local AS dealer

situation: the tv and brake controller work great on level and uphill climbs; also on moderate downhill slopes.

however, on some steep downhill sections the TV transmission will go into a high-rev mode when i use the brakes. there is no wobble or sway from either the TV or the AS. I can usually kick it down but the high revs worry me.

since i have the tow/haul option should i be driving in "D"? or in another gear?

has anyone else had this same problem?

i read somewhere the the ford transmission will go into high rev but that there is a safety mechanism which prevents motor damage.

any input would be greatly appreciated,

az-streamer

[AirHeadsRus]

I tow with my 07 F-150 sometimes. I tow with the tow/haul on and in D.
I have never had it rev when braking. Have you asked the Ford dealer about this or is anything in your manual?
Regards,
joe

[flmgrip]

Isn't engine braking a good thing? You can probably avoid it by turning off tow mode...

[HowieE]

When you are using Tow Haul Mode the trans will down shift during braking. This is a design feature to reduce the ware on the brakes. The steeper the hill the sooner and greater the down shift may be. If things are working right the trans should down shift one gear at a time as you slow keeping the engine RPMs high enough to produce effective engine braking.

I don't think you have a problem you just have to get used to the new design.

[azflycaster]

My Tundra downshifts when I hit the brakes on long downhills. I consider this a good thing since the engine breaking will reduce the amount of brake I need to keep the speed I want.

[Airslide]

Engine braking is a good thing. In the Tow/Haul mode and possibly under certain decents the logic built into the transmission control module will allow for engine braking. In the case of over-reving it would then upshift before you blow the engine. All of these scenereo's have been tested and optimized for as many possible situations you could find yourself in. When its in Tow/haul mode that tells the ECM and TCM the truck is under heavy service and to behave a different way.

Vinnie

[2airishuman]

post MORE details.

what speed?
what RPMs?
what grade?

my understanding is the tranny will down shift TWICE in t/h mode...

1. one time for STEEP declines

2. and a 2nd time IF the truck brakes are applied downhill.

touching the go pedal briefly will up shift.
________

and this will happen when NOT towing as well,

so u can test the system without the trailer involved.

that would be using the "haul" mode...

cheers
2air'

[az-streamer]

thanks to all for the replies.

i feel a little better knowing that this is probably a normal reaction to hauling a substancial load down a hill.

on a decline, i try to keep my speed within the posted range, or even lower.

the transmission usually runs around 2 on the level but revs to about 4 before i can get it to drop back down.

the hills are all regular highway - i guess the worst at about 5-6 degrees down. ik don't speed - not good for the AS the TV or my nerves.

this happened on a recent trip my wife and i made to dead horse s.p. in cottonwood az. while driving on I-17.

this has not happened at all when i not towing the as.

az-streamer