THUMP..what the??

[Bad340fish]

I pulled a Vintage 24' trailer this weekend loaded to about 7K. I noticed a very obvious THUMP when leaving intersections and sometimes when stopping. The ball mount is a Putnam class 4(Heavy sucker) with a 2 5/16 ball I checked to make sure the pin size was right which it was. The ball is tight. The hitch recall has been done and i can see no evidence of the hitch moving on the truck. And it has done this with another trailer and different ballmount also. Anyone else have this problem?? I bought the truck used and it had apparently never been hooked to a trailer(No scratches in reciever tube). Any help would be appreciated. It goes to the dealer soon for the coolant noise TSB so if i don't find anything here i will have them check it out. Thanks for any replys


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Clark
1999 2500 QC SB 5spd Flowmaster 3 chamber, K&N Re-0880
1968 Barracuda Formula S Viper Blue 11. 98@112

NHRA member for life

 

[boatpuller]

Does the trailer have surgebrakes, if so could it be the trailer and not your hitch? Surge brake couplers will really jerk alot if the brakes are out of adjustment.
Hope this helps.
Caleb Reese

 

[QRTRHRS]

Do you get the "thump" when you let off or accelerate or only in conjunction with the brakes? Try throwing the truck into neutral then braking to eliminate driveline play. Get someone to listen and watch from outside while you move around a quiet parking lot. Do you have someone else who can pull your trailer to see if it does that to them?

 

[Rambling]

I agree with Boatpuller on the possibility of it being in the trailer brake system.

It could be you have a brake that's not working quite right. It might not be releasing as quick as it should. It makes the thump as the brake releases and there's a slight rebound forward by the trailer. The brake may also coming on too quickly or grabbing causing a thump as it takes up slack.

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<font color=#990000>~<font color=#990000> '99 2500 SLT <font color=#990000> ~ QC ~ 4X4 ~ LB ~ Auto ~ 4:10 LSD ~
<font color=#000000>*<font color=#990000> BD E-brake<font color=#000000> *<font color=#990000> BD Autolock<font color=#00000> *<font color=#990000> Gear Vendor OD<font color=#000000> *<font color=#990000> Jordan Research 2020 T-brake <font color=#000000> *<font color=#990000> Bullhide spray-in Line <font color=#000000>*
<font color=#000000>*<font color=#990000> 2k Komfort 5'er - 9,700 lbs <font color=#000000> *
<font size=-2>... Lookin' for the 'RE' to go in front of my 'TIRED' so's I got more time to Play!... <font size=-1>

[This message has been edited by Rattlin (edited 02-19-2001). ]

 

[Gary - K7GLD]

Wonder if your truck has a 2-piece driveshaft? Those can frequently allow the driveshaft to shift *vigorously* inside the center carrier housing - and usually as you accellerate/decellerate - it will make a pronounced "thump" and will sometimes also create a "shudder" on accelleration, like from a stoplite under moderate throttle. Other than that, check rear springs, shackles and shock absorbers for wear or looseness...

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http://community. webshots.com/user/davison71 Early '91 250, 727 AT, 307 rear... Banks Stinger exhaust, intercooler... US Gear OD... MORE than a match for every new PS Ford encountered so far...

 

[Bad340fish]

Thanks for the replys. No the trailer does not have surge brakes. I am running a Tekonsha Sentinel Controller. Next time i pull i will see what it does with the brakes off. It only did it stopping once. But it would almost always thump when i left an intersection, if it didn't to it right off it did it when i went to second. First thing i checked was to see if the car was still tied down #ad
thats what it felt like at first. Thanks

Clark

 

[JohnB]

I'll bet on Gary's suggestion, the driveshaft slip joint. I have had this happen, slip joint splines get dry and as the truck takes different attitudes braking and taking off it will slip suddenly after being in a bind. Try grease-I bet it goes away---good luck

 

[Bob Stephens]

Bad340fish, do you have a weight distributing hitch setup with torque bars and chains? My old travel trailer would clunk when starting up if you came to a sort of fast stop and then started up rather quickly. It was the chains on the torque bars shifting from stop to start. Also, you'll be surprised how much play is in the receiver even if it seems tight.

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2001. 5 White 3500 Quad Cab 4x4 Sport SLT+, ETH/DEE, 4. 10 Anti-Spin Axle, Camper Special Group, Trailer Tow Group, Tekonshs Sentinel Brake Controller. Preparing to add Guages, Line-X, 20. 5 Pullrite Hitch, DEE-ZEE FX Running Boards, Exhaust Brake, ICOM 706MkIIG HF Radio (maybe more later). Pulling 99 Hitchhiker II 30RK fiver and ordering 2001 Alpenlite 35RK fiver.
Ham Call: AF9W/7

 

[Guest00]

Check to see if you have a 5/8" dia reciever pin. A 1/2" pin will give the same symtoms. The pin should be snug in the hole with no fore to back thrust.
My $. 02