Engine/Transmission (1994 - 1998) truck bucks when towing, just did 3gsk and plate

[GMichaels]

have a 97 3500 drw 4:10 5spd with a 10 plate and 3gskit. before the kit the truck towed fine, although it did not have much power.



when to get a small dozer (case 310), on the way down the truck had no problems, was towing a 6000lb gooseeck trailer (empty). could go up 12% grades at 60 no problem egts at 800. great.



loaded the dozer and within a mile the truck started to buck and bounce very hard at 40mph level grade. if you let off the pedal it would smooth out. it was so bad I thought I had a trailer problem and moved the dozer to shift the weight towards the truck. no difference. so I took the next 170 miles at 35 mph, and down hills much faster.



Now this problem seemed to go away for about 30 miles, and than came back.



before the upgrades I towed this dozer with no problems. although not for a long distance.



could it be the govenor springs? seems to happen around 1750 rpm, in general.



I thought maybe bad fuel? its only 10 degrees, but the motor seems to run fine.



my last guess maybe would be U joint which I will check inthe morning.



need some ideas on troubleshoting this.

 

[Vaughn MacKenzie]

It could be you need new throttle return springs. I heard this often solves bucking problems that occur when towing after a GSK has been installed.

 

[Forrest]

I had the same problem ...



http://dodgeram.info/tsb/1997/18-29-97.htm



Vaughn is right. There are 2 springs in parallel in the linkage setup. Adding another or changing one or both to stiffer has worked.

 

[Turbo Thom]

Plus, I would back off the springs one click. Tight springs will buck like a bronco with a cukle burr stuck between it's legs.

 

[GMichaels]

Did you purchase the kit (see tsb link in this thread) or just add new springs? thanks for this info.

 

[Forrest]

I purchased the kit. The linkage in the kit has a bit different geometry, if I remember right.



Of course, after getting the kit on, all was fine, then someone posted about simply swapping out one of the springs, or something like that ...



If you do some diggin', there might even be a part# somewhere. When I went through this, I went to the dealer & they didn't have the right pictures of the pump linkage. Their spring part #'s weren't even right & I ordered one, didn't have the right connectors on the ends ... totally wrong. The Cummins dealer told me to go to Dodge. :-laf



The post about the spring/s was just a throttle return spring. Simple Pep-Boys, aftermarket universal type spring stuff. I'll bet if you go out & measure the length of the springs, you can go down & buy a handful in that length & start pulgging.



Oh ... just for grins, try this. With your left hand, move the throttle cable to the left 1/2 way or so through it's movement. Reach down with your right hand & move the linkage, around the double spring area, back & forth. Mine moved really easily down there, back & forth. BINGO. With some throttle, there isn't enough spring tension to keep the linkage from oscillating back & forth. Really a pisser when you're towing up a hill. :{

 

[cahammer]

just replaced my springs with some every parts store has em springs and that stoped my bucking but dont get too stiff of spring unless you love to stand on the gas pedel to make it move

 

[CATCRACKER]

gsk solved my bucking did not cause it. the defueling with 370's was starving engine for fuel 3gks fixed it.

 

[GMichaels]

Talked with Piers diesel, said this is a common problem, explained that if rpm went up after gsk install, chances are you need to back off the gov spring by one click. also explained that rpm should follow your foot and not jump up.



I will back off the spring tension and check into the throttle springs,

 

[GMichaels]

I have read that to tight on the gov springs is a problem. Is there a down side on to lose? I backed off the springs a click and a little worried about those adjusters coming off.



they are one click past a soft click. still . . 070 measurement. piers says average is . 05 . idle went down 200.



so is there a down side?



and about the throttle return springs, i just looked, so did you just wrap them around the posts? or do they sell the snap in type like whats on there.

 

[WDimig]

it sounds about right. dont worry about the keepers coming off, theres always pressure on them, and as long as they are seated, the pressure from the gov. springs will not let them come off.



wes