wyoltapilot

Hi, Newbie here. I’ve been lurking for a couple of months, trying to soak up as much info as I can.

A few months ago, I bought my fathers 96' 3500 dually. It has 130k on it. He has always treated it with kid gloves. He used to pull a 4 horse trailer with it. Although not often and not at all for the last 4 years. Also it has a pop up truck camper unit. Most of the miles on it, are hwy with the camper on. Living in Wyoming, there isn't a whole lot of city driving.

Also it has the 5 spd manual trans with original clutch.

I admit I am new to Diesel ownership. However, not new to manual transmissions.

Here’s my problem...

When I start from a stand still in 1st, 2nd, or reverse, the truck seems to hop or buck a little. If I really feather the clutch I can make it take off smoothly. But that seems like that would be really wearing down the clutch. After I’m rolling, It shifts smoothly, it isn't hard to get into any gear. Once the engine heats up, the problem seems to go away. The clutch pedal feels like it always has from day one that I have owned it. This problem started about a week ago. There doesn't seem to be any slippage.

I'm really worried about it, I really don't want to be causing any inadvertant damage by letting this go until it "breaks". I really don't think it is the way I drive, I am pretty conservative, I've torn up several vehicles in the past by driving the hell out of em, I'd like this one to last a while. I have pleanty of exp driving manual trans, from my sisters rice burner, to my Father-In-Law's cabover. The only thing I have killed the clutch in was an old John Deere 4520. So I don't think it's me, but.....I wouldn't rule myself out yet...

Is the clutch due for replacement? Is it something more?

What else would be helpful for you all to know?

Thanks in advance.

waldersha

Mine did that too, until I turned the starwheel up a bit. Don't know if turning the idle up a little would help or not, but might be worth a try.

RCW

Have the truck timed. What happens is they lose power as the timing backs down over the years, and eventually they will buck and pitch when cold if the timing is below the recommended level. This happens so slowly that most people never even notice it until something brings it to their attention like crummy fuel economy or the power is down a bit.

As a rule of thumb, all 12 valves from 94-98 will have slipped timing unless someone has reset them. The factory torque value was too low for the injection pump timing gear nut, and it lets the gear slowly slip away over the years. Once it is set properly and torqued it will stay forever - unless you move it again.

wyoltapilot

Well I have noticed a decline in fuel economy. My father suggested I replace the air filter, so I was going to go buy one shortly.

He did say he had the "valves adjusted" Is that what you mean by "timed" if not, is that something that your average shop could do, or do I need to take it a dealer?

I'll also have to look up what the "starwheel" is but i'll look into it. I will say though, it seems to idle just great. I don't hear any anomalies, Granted I don't have a trained ear, but it seems to have that awesome Cummins purr, like it has always had

Thanks.

waldersha

Valves adjusted means that instead of having hydraulic lifters yours has manual ones. They have to be set to certain specs in order for everything to run smoothly. Do a search on adjust valves and you'll find all sorts of information. Of course, you'll find lots of information about anything you ever wanted to know about these trucks.

The starwheel is inside the AFC (air fuel control) box behind the injector pump. It controls the air and fuel mixture in the engine. Clever name huh? Basically if you open your hood and look above your fuel filter you will see a box with a allen head screw in it. If you take that screw out you can see the starwheel. Adjust with a flat screwdriver, towards the engine for more fuel. Try a couple of clicks and see if that fixes it for you.

Timing can be done yourself but is costly to get the tools for and a bit advanced for me. From looking on this site it looks like $200 is about the going rate for a shop to do it. The starwheel adjustment is free, so I would try it first. There are several other free mods that you can do to your truck to keep you happy for a while. Search around and have fun.

Good luck!

wyoltapilot

Ok, I put in a new air filter this evening, The filter was defiantly needing to be replaced. When i took it out and tossed it on the driveway, I was amazed at the rather large plume of dust that came out of it. I did notice an increase in power with the new air filter. I am hoping that will help with the air/fuel mixture. Oh and just for the heck of it, while I was in there I pulled out the silencer ring.

Another suggestion that a friend of mine offered up, was the rear end. I thought I'd run that one past you all. Could the rear end be causing the problem I described before? What are the signs of rear end problems. What made him suggest something might be up with the rear end was when I said that, last month in a snow storm we had, I locked up the rear brakes...well it is supposed to have ABS, so why did it lock up? Any thoughts?

Thanks again.

waldersha

What happens if you goose it a bit when you take off? Do you still get the buck or is it only when you try to start up regularly (slowly)? Really doubt that it would be a rear end thing since it works okay other than at start up.

In my experience the brakes on these are strange creatures anyway. Might check for leaking axle seals in the rear, those will make your brakes grab, but you would probably notice that at other times too.

Remember you have RWAL brakes on that anyway, so the fronts aren't anti-lock and will lock up on you. Always seemed strange to me that they were that way.

Sprinter17

Check for a worn out transmission or motor mounts.

tool

I've had the exact same thing with my truck, turned out to be caused by 2 things.

1. oil soaked clutch plate (replaced clutch)

2. broken transmission mount.

I would bet your problem is clutch related, mine got progressively worse until it started to slip, took many months and thousands of miles before it died.

maddog55

Now you got me worried. Clutch started slipping on my 99. Had it changed at a good tranny and axle shop. I bought the clutch myself ftom a company in Idaho. Now it chatters like crazy. I can control it if i feather it going forward. But reverse absolutely suck. It chatters, skips the tires, ant sloshes my coke or coffee out of my cup.

I hope it is a loose or broken mount. If it is the clutch, I do not know if that company in Idaho that sold it to me wil make good.

Here is hopin!!

the MADDOG