Did it today
Took me about 2 hrs, but not hard like I was imagining. I feel the truck go (hit) thru the gears much strongerand with more authority.
I added Redline synthetic while I was doing a tranny flush, 18 Qts. Ihope to extend trans. life greatly with this, I have 178,000 on her now.


Hanklin

 

congratulations.
i also thought it was alot easier then what i had planned it to be. you're going to love it when towing.

 

Yeah I plan on towing a small trailer on Sunday morning to go motorcycle riding (3 bikes,1Quad). But you can be sure I`ll be home for Nascar, we`ll see how different it is towing,thanks strokin it 73

Hanklin
go # 20

 

I know I was greatly impressed with the difference when towing the 5th wheel this last weekend. Trailer weighs in about 10K loaded up. Between the sonnax mod and putting on the BTM, it seemed to take the hills much easier.

 

Did yours every shift really hard with the trailer in tow? Since I've done this mod it will shift very hard once in a while just going up hill at about medium acceleration. It seems to shift better at light throttle and all the way to the floor throttle (both going up hill, flat ground seems good all the time).

 

i have noticed a hard shift every once in awhile with the 5ver behind me... i try to figure out what the conditions were when it happened and make sure those conditions don't occur again... as you say, throttle position seems to be the biggest factor... when i tow, i try to be either very light on the pedal, or right down on it... the inbetween area seems to be more prone to the "clunk shift".. the other thing i try to do is to make sure i am off the pedal when it shifts into overdrive... i usually push the button to shut od off until i can get up to speed and on the flat or maybe a slight downhill then i can lift off the pedal and still maintain speed... once i get there i can turn the od on and it will go right in with minimal wear on the clutch pack... once i'm in od running about 75mph lookout...! i'm not slowin' down for nobody..! lol..!

 

No I didn't notice any hard shifts with the trailer, I don't really think it shifts hard without either. I do notice the shifts more now, but I wouldn't say they are hard shifts by anymeans. I am definately not getting a clunk or slamming shift. I do know it shifts smoother under heavy accelerations.

 

I have the original SCMT 1700 but haven't been running it since last summer. Today I installed the tow safe setting. It shifts better now regarding the medium acceleration shifts I mentioned above. Has anyone else experienced this type of Sonnax modded tranny improvments with a tuner installed? And, upon heavy acceleration from a stop I notice a light vibration or shutter, but just for a second. Is this because of the weak stock torque converter?

 

no orezona, that is the carrier bearing in the driveshaft. you need to shim the center carrier bearing down to make the drive shaft line straighter. ill PM you the part numbers if i can find it.

 

Sounds great. Thanks.

 

Most of the time the shutter comes from the carrier bearing. However, if the T/C is slipping and not locking, it will present the same symtoms.

https://www.ford-trucks.com/forums/s...8&goto=newpost

 

It only does it with the SCMT installed.

 

How bout the converter lock up switch?

 

Question - My truck shifts fine with or without pulling my trailer - 7k. Should I still consider doing this mod to extend the life of my tranny? I have 105k miles on the truck.

 

it would help eliminate the "soft shifts" that the tranny is programmed to do.. those help increase the tranny temps... more important i think is to get an additional tranny cooler to make sure any extra heat you make while towing is effectively dissapated..! excessive heat is guaranteed to shorten the life of your tranny...