I pulled a 18' tandem axle flat deck with a skid loader and two buckets this weekend, estimated weight 9,500-10,000 lbs.
I hooked to the trailer and as soon as I put it In gear and gave it throttle the whole truck would shudder badly through 2nd. The easier I accelerated the less it would shake, but it was a rough ride. On the highway I held 60-65, only using OD down hills a dead flat areas. Held about 2 k rpm the whole time for 60 miles.
When I got off he highway I paid closer attention to rpms and found that if I allowed the truck to shift on its own, it will shift Into 3rd at 30 mph at 2k rpm and the rpm will hang there until I get up to 60. That seems like a ton of slip to me especially considering the converter should start to stall around 1600.

Trans fluid is brand new dex 3 checked in neutral running. Converter is the tightest one from goerends with less than 10 k miles on it. Bands are all adjusted in the last 1000 miles and I turned the shift pressure and other screw while I was in there.
Truck drive pretty well empty (no trailer) and can easily hit 90+mph. But it still shudders in 1 st and 2nd.

Ideas? Thanks.

 

Could be the OD straight clutch slipping under the higher torque of the lower gears.

OD is the weak link, is not very well oiled or filtered, and if it goes enough to spall the ball bearing in it, it'll take out your whole transmission. Don't ask how I know that.

You can pop it off in frame, and overhaul it. Takes a couple of special tools, but you can make them if needed. Put a stiffer straight clutch spring in it while you're at it, and better frictions.

If it's been chattering, the bearing I speak of is toast, even if it feels fine. Change it.

 

Sound like what my 47rh was doing right before it totally let go. It would shutter going into 2nd and then seemed fine after that. A few hundred miles later I lost all forward gears.

 

When I was at highway speed and shifted into OD the trick really accelerated right away without adding more throttle than it took to maintain speed in 3rd. Does this point to OD being the problem still?

 

So you turned the shift pressure and other screw while you were in there????

Um, what were you trying to do?
What is the 'other screw'?
By shift pressure are you trying to turn UP the line pressure??
Are you aware that it is turned CCW to raise the pressure?

The way you worded it makes us think you don't know what you did.
If you lowered the pressure the trans will slip.

Find out how to put a gauge on it to see what pressures it is at. There mor ethan 1 pressure test by the way.

 

What he said!

 

I followed the thread in the stickey for band adjustment and line pressure. Also changed the filter and fluid. I did this to try and eliminate the shudder but it did not help at all.
I can feel it shift firmer and at higher rpm, just didn't solve the shudder. I've also replaced the driveshaft support bearing, which needed to be done but did not solve the problem.

 

The overdrive is in the output. All the torque put out by the transmission, which would be engine torque, multiplied by the conversion factor of the TC, multiplied by the gear ratio in use. In low gear, it amounts to about a ton. In high gear straight, it's just engine torque times TC multiplier, maybe 600 ft/lbs at full throttle.

A spring holds the straight through clutch engaged. Thst's the clutch that's slipping in low gears in all probability.

The no throttle added quick acceleration indicates you were up against the IP governor.