3408 problems

Is this power unit in a truck or is it a stationary power unit? It sounds as if either one of two things are happening. First is the intake from where the air comes in the air cleaner to the turbo clear of obstructions. Second if attached to a piece of equipment is whatever its driving IE pumps, hydraulics or other attachment are they locking up holding the engine back. We need to know if this is in a truck or not.

 

In addition to what I just posted I had moved an excavator about 300 miles mostly on the interstate at 65mph upon arrival at drop location had same problem couldn't get it to run. The rubber ring around the air cleaner stack had pushed up blocking the intake to the air cleaner stopping the air flow. The other incident happened in a truck I owned that had a Cat retarder. The valve that charges the retarder with oil had stuck in the on position. With the retarder fully ingauged it would not let the engine run.

 

Almost sounds like a lack of compression especially sense it takes a lot of ether to start and wont idle. Or something has failed in the transmission and the torque converter is draging the engine down.

 

I agree with Roberts450 lack of compression or torque converter problem either way unless you are a certified Caterpillar mechanic and have done this before ( I am a Certified Cat mechanic the loader you are working on is a 988B-C or D MODEL its the only one that used the 3408) If you call Cat repair or someone who knows and has the test instruments they should be able to tell you in minutes what the problem is IE engine or converter/trans

 

That is the problem the pieces or tools you need are made by Cat. They can be purchased but are quite expensive to buy for one job you may never do again. In the long run its cost efficient to have a Cat repair person come to your location and do the diagnostics and repair because there are other special tools that are used in the convertor or engine repair as well. Its just easier and cheaper to call and have them do it. You also get a warranty when its done that way.

 

Have you check the hydraulic pumps on the back of the engine they will lock the engine the same way if one of the control valves is on and dead heading the pump. Check all the thumb switchs on the controls in the cab and unplug them to check it. It would be a cheap and easy fix if that were the problem.

 

Make sure the bucket lift or tilt isn't locked in the detent. We fought a 980 for a few minutes that the operator had killed it with the bucket lift locked in. It would turn over just fine, but not quite enough for it to start.