I will be tearing into a friend's 2002 Chevrolet Express 3500 soon. I just briefly peeked at it thus far.

About 3 weeks ago, a local shop replaced the alternator, water pump, and serpentine belt.

Pretty much immeditely after receiving the van back from the shop, I am being told that the transmission was repeatedly low and would not engage until being filled. I am not sure how much fluid they were putting in or if it was actually leaking out or not.

Today, for the first time ever, the transmission will not engage at all, even in manual 1. On top of that, there is absolutely no power brake assist or power steering. My friend said that if you pushed the brakes hard enough, the ABS light would illuminate. I was not able to re-produce this light, though.

The engine RPMs drop when putting transmission in gear, but it will not move, not even when providing the accelerator pedal.

I am curious if anyone else has experienced any of these issues simultaneously, or if this is purely a coincidence. There is no CEL on so I have not attempted to retrieve codes.

Thanks.

 

I investigated the issues. They are clearly separate issues because:

One of the two lines that run to the transmission's auxiliary cooler in front of the A/C condenser has a pin hole leak, due to rust. So the transmission fluid is constantly leaking from this. That is why they have re-filled the transmission and then the transmission will engage again. The amount of wear that has been done to the transmission as a result is unknown. All of the cooler lines are rusty and should be replaced. There was plastic corrugated tubing placed over the metal cooler lines which must have held moisture behind it, which caused the lines to rust.

There is some sort of "goofy" device behind the brake master cylinder. It is not a traditional vacuum booster as I am accustomed to. It appears that the power steering reservoir line runs to this device, and there is also a "gold" cylinder on the side that says "warning, pressurized gas" or something like that.

So it is likely that this "goofy" device is the cause of having no power steering and no power brake assist.

What is this called? It is clearly not a vacuum brake booster. In fact, I do not even see any vacuum lines running to it.

 

The brakes are hydraboost, and run off the power steering pump. Those lines are brutal for leaking. That is why there is no vacuum diaphram.

 

The only lines that are leaking are the transmission's auxiliary cooler lines. The power steering reservoir is full. There is some slight "wetness" at the junction between the master cylinder and the hydraulic boost unit, but it doesn't look fresh. Perhaps the pump is not working, or the shaft in the pump has broken? When the motor is running, I do not see any agitation of the fluid inside of the reservoir.

 

Do these vans also have a power steering cooler integrated into the radiator? There are another two cooler lines running into the driver side of the radiator. I know the lines at the passenger side are for the transmission cooler...

 

Drivers side is oil cooler lines.

 

Oh ok. In that case, the engine oil cooler lines look to be in good shape.

It is just the lines for the auxiliary transmissions cooler that have the plastic tubing over them. Trapping moisture.

I will have a better look at it tomorrow.

Is there any good way to test to see if the power steering pump shaft has broken, versus the hydro boost unit itself?

 

Why do you ask? Are you having issues with the power steering or brake assist?
If the pump was not working it would take both hands and your foot on the engine cover to reef on the steering wheel to turn it while the van is sitting.
Same for the brakes.....you would have to stand on the pedal with both feet.....and pray....lol.

 

Yes absolutely, there is no power brake assist AND power steering. From what I am being told, both issues occurred simultaneously for the first time on Tuesday morning.

So this points towards being the pump being the culprit, rather than the hydro boost assembly behind the master cylinder itself? I thought that either item could fail, causing the above symptom of having no power brakes or power steering.

I am just unsure of which of these two items is to blame for the failure....the pump or the hydro boost assembly.

 

I would bet the pump. It creates the system pressure.