Jerking while towing

[09wyoblue]

I have only found one thread discussing this issue last year and I didn't find any real answers in it so I thought I would ask if anyone has found any solutions in the mean time. I tow a lot with my 09 F350 CCLB Stage II AFE, Flo-Pro 5" and Erics tunes 355 gears and 35" tires. I pull gooseneck trailers that empty weigh about 4,500 lbs. and load them up to another 20,000 at times. Often tow around 15,000 gross. I experience the "jerk" empty to fully loaded. It feels like when you are pulling someone who is broke down with a chain and they can't keep the chain tight and the slack keeps yanking on you. I often have to tow on highways where the speed limits change from 45 to 55 to 65 and between 45 and 60 the jerking is horrible. This is my first auto tranny ever and I am really hating my decision. I experience this on 80 hp, 215 hp, and 300 hp in high range or low range in the t-case and stock or firmer as well as delay lock tranny programs. I have experienced it in my friends truck with canned SCT tunes at lower power levels and KEM tunes as well. Yes we both have adjustable pedals BUT I have tried accelerating using just the cruise control accel button and the jerk still happens although slightly less violent because the first jerk doesn't compound things by bouncing my foot. Using the Torque Converter Slip RPM function in my Dash DAQ I have found that the jerk occurs when the torque converter locks. I can make the jerk occur at different times by using the stock lock and delay lock programs in my SCT. Has anyone found a way to prevent this from happening? Is it the pinion angle? Is it slack in the drivelines/drivetrain? Is it the torque converter "shuddering" as it tries to lock? Would delaying the lock even further help? Does anyone with an aftermarket torque converter still experience the jerk.

 

[Spatel23]

the first question most people are going to ask is if you have traction bars?

 

[bad12jr]

Try another trailer. Had one do that the the axles were to far forward and the adapter was set up to high for my obs. Hooked another trailer with a better setup axle configuration and the trailer pretty level. It pulls like a dream. Hit a bump going 65 and it never even offered to jerk.

Sent from my x2 somewhere

 

[Smokyred]

6.4's can have a buck when towing tuned, from my personal experience it was always at the same RPM. Speed up or slow down and it went away.

I can get mine to buck in the 310EL right around 58mph if I'm wearing boots and on a rough road. With flip flops on it doesn't buck, same stretch of road. And that's just the truck, no trailer.

I would think mine will go away once my traction bars go on.

Dave

 

[09wyoblue]

the first question most people are going to ask is if you have traction bars?

Thanks for the reply Spatel. No I don't have traction bars. Has someone who has my problem put on bars and had it resolved?

 

[03f3507.3]

My 6.4 did the same thing on 275 and 310 spartan tunes if i backed it down to 210 i was good to go no problems at all.

 

[09wyoblue]

Try another trailer. Had one do that the the axles were to far forward and the adapter was set up to high for my obs. Hooked another trailer with a better setup axle configuration and the trailer pretty level. It pulls like a dream. Hit a bump going 65 and it never even offered to jerk.

I am familiar your problem and this is not it. I generally pull two different trailers a flat bed and a stock trailer but have also pulled 3 other flatbeds, another stock trailer, a short horse trailer and a bumper hitch 12' enclosed trailer and 20' bumper hitch sled trailer and it occurs with all of them. It happens when the torque converter is locking.

 

[09wyoblue]

My 6.4 did the same thing on 275 and 310 spartan tunes if i backed it down to 210 i was good to go no problems at all.

Do you know if your transmission control module is programmed to shift firmer at 210 than it does at stock? My jerk occurs at the 215 hp level and even clear down to 80 hp though it might be a little less severe. I am wondering if the torque converter locking sends a jolt through the drivetrain which is really compounded in the slack found having a cclb. Does anyone have a top link axle locating kit? I have kind of shied away from traction bars because I ranch in the Rocky Mountains which means often shoveling out of the snow and traction bars are a royal pain to dig around.

 

[Black_Pstroke]

Ive been noticing mine doing this lately empty. Usually around 55mph, gonna have to break down and get some traction bars

 

[SEABEE08FX4]

Why are you towing with a race tune? Thats your first problem, unless you like costly repairs I'd step it down to a smaller tune. No need for a tune any larger than 200 for towing, hell I use a 150 hp tune for towing and it works like a champ.

 

[09wyoblue]

Why are you towing with a race tune? Thats your first problem, unless you like costly repairs I'd step it down to a smaller tune. No need for a tune any larger than 200 for towing, hell I use a 150 hp tune for towing and it works like a champ.

The 210 hp tune is labeled TOW TUNE.

 

[SEABEE08FX4]

Right, I'm referring to the use of the 275 and 300 and up tunes. I'm not trying to bust your balls but we get customers in here all the time that do this will negative results. I have a customers 06 cummins in here right now that melted 5 out of the 6 pistons because he was pulling 16,500 in a race tune. Just saying its not in your best interest to do it. Take it for what you think its worth but the higher HP tunes were never designed and or intended for towing.

 

[Humphrey99]

My stock '08 F250 CCSB does a similar thing only not as regular as yours seems to be. I've had it do it with different trailers and even empty when downshifting to 4th to pass cars in the slow lane up big hills. I usually only notice it in 4th, but sometimes I think I feel it slightly in other gears. It happens so infrequently that I haven't been able to figure out the right combo of throttle/load/environment to make it happen repeatably. Your description is the closest thing I've found to doing the same thing as mine, but in other threads with similar type problems, guys are replacing what they call a gogo solenoid and is helping some. I didn't know if this was my problem or when I put a tuner on with higher pressures to firm up the shifts if that would help. Hopefully you can get it figured out. I'm just going to see what a tuner does before I do anything else. Good luck man.

 

[BFT]

Larger tunes normally have a touchy throttle. That can be another issue.

 

[SAK]

The jerking is caused because of the axle wrapping. It happens a lot easier on the 08+ truck due to having longer leaf springs. The only real solution for the problem is traction bars. If you would like some info on the OUO Traction Bars just let me know.

 

[Humphrey99]

I would have thought axle wrap (at least in my case) would be worse in lower gears. Also happen consistently instead of every once in awhile when the stars align. I'm not saying it's not axle wrap. Just what I would have thought. I may have different issues with similar symptoms than the original post too. Hard to tell without being in the seat.

 

[BK39]

Mine does it too. Not all the time, but every once in a while. It use to only do it with 310 tune. But I've gone as low as 250 tune, and it will still do it. So I'm interested to see what you come up with. I do not think mine is axle wrap nor touchy throttle. I recall someone saying fuel filters back in the day, but I change those often. Even with new Filters still does it.


Edit: Mine does it loaded or unloaded, doesn't matter.

 

[Dustball8504]

Mine did it on the 250 and 275 tunes before the traction bars. It would do it even with an empty trailer behind it that weighs about 3500lbs.

 

[Motostroker]

its the touchy throttle causing mine to jerk. i have trac bars and it still does it. IMO its a tuning issue. I would like to tune mine where the first bit of throttle barely fuels.

 

[09wyoblue]

At the higher hp levels like 250 or 300 I think it is somewhat due to touchy throttle. I deal with touchy throttle all the time on my 2000. I have only towed an empty sled trailer once a short distance on 300 and I think the "jerk" was different. I tow on 215hp sometimes if I am pulling less than 5k gross, but mostly I tow on the 80hp level. I have driven my friend's truck with the canned SCT tow tune which I think is only 45 or 50 hp with a 4k load and it jerked too. I think I may have try some air bags I have laying around just to see what happens going off of the premise that the torque converter locking sends a jolt that causes some axle wrap that may bounce back and forth off of my overload springs.