I am tired of towing my trailer (8,000 lbs.) down the road at only 55-60. On a flat you can coax it into o/d and do 65, but you better not budge your foot in the slightest or you are back to 3rd. So with my upcoming swap what should i do to get faster towing speeds? On the same line; I used to go barking up a 6 % grade at 90 mph, I even beat my father-in-laws tuned up 2nd gen side by side. the truck won't do that anymore. This is all before a new supposedly better billet torque converter. Don't tell me this thing is tired already, but it just seems to have lost a step.

I think its in my sig, but here is my truck

91.5 with 518 Over Drive Automatic
High flow exhaust and slight turn up of the fuel screw
235 tires and 3.54 gears

 

I have this problem also. Tranny was rebuilt, (not by me) and a single disc billet TC dropped in. Top speed is around 67mph, and if I try to give it more, it'll drop out of OD. !!Do I just need to adjust line pressure? Or could it be the VSS?

 

Sounds like you guys need the G360 mod. Roughly 40% more power to the wheels. Works every time.

 

I was thinking the same...

 

The jumping out of od could be a bad tps or an out of adjustment tps.

 

x2 on tps

 

This is why I shift my own gears. Every auto (518) I have ever seen was junk. I say its time for a nv4500!

 

A stock 518 can have its issues but when they are right they are right!

 

tps is set. o/d really isn't meant to be going down the road at 70; but i still want to. how about the line pressure? I am in the middle of a conversion to a crew cab (i won;t be swapping drivetrain till spring or early summer) and the truck is going to stay an auto, i think.

 

What do you mean od isnt meant for going 70?

 

It's not meant for towing more or less.

 

I disagree. You just can't go slow in OD when towing, you gotta kick it out if your putt putting at like 45 mph in OD.

I tow at 70+ no problemo (if EGT's and coolant temps permit)

 

Which means you'll be stuck going 55 flat out! I don't want a 'rag on my tow rig, 'cause I haul livestock and I can't shift it smooth enough every time. I don't want no $100k horse breaking a leg.
Yeah, I've thought maybe the TPS is the culprit, but haven't been out to check if the voltage sweeps like it should. One of these days I'll get around to it, but no rush 'cause I'm in rebuild mode right now.

 

I have towed more than 8,000 pounds and was in od and going 75 never had a problem. Like head said the problem in od comes when you are going slow.

 

Ditch the slushbox and go with a Rag or NV.

I cruise 70+ all day with the old mans truck grossing 21,000, thats about 15,000lb trailer and load. Handles it like a champ.

8,000lbs aint that much, shoot my truck and suitcase weights are 8500.

Do a manual swap, you'll never regret it.