My '92 245, with 125,000 miles, has recently developed automatic transmission problems. It will down shift when I am going 70-80 mph on the interstate and I hit a bump. The transmission corrected itself once and the other two times I had to pull over, move the shift, then everything was fine. Today, the car would not shift into 3rd gear until I hit bump. I had the transmission fluid and filter changed in May. Any help is appreciated!

Thanks in advance

Molly

Next time it won't shift into what is most likely OD, wack the dash on the upper left corner. I am not kidding. Give it a firm, open-handed wack. If it shifts into overdrive, you have a bad OD relay.

I assume it will NOT shift into overdrive with the relay wack because I am guessing that the wiring to the OD solenoid is bad. If you want you can check this one out while moving also. Remove the two screws that hold the shift indicator plate down and move it a little forward. There should be a white wire that disappears under the car. Have a helper wiggle that wire while driving at 50-60 MPH. You will probably jump into OD or out of it as the wire is wiggled. A better way is to get under the car and actually inspect it.

If it is the relay, resolder it. It will be better than a new relay which will eventually suffer the same fate. The wiring should be replaced if it is bad and all splices should be made watertight.

Onkel Udo

By "resolder" do you mean just reheat the solder points along the base of the relay? Also, does anyone know of a place to get a relay online (ie: decent price)?

Thanks for the help.

Look at the ads on the Brickboard, also Ebay has them from time to time.

Question about the overdrive relay. I pulled my relay and I'm about to resolder it... however I noticed something old. If you hold it with the prongs down and the bottom towards you, on the upper right corner of the board there is a stretch of solder which appears bronze in color. Is that part of the etching process and shows a spot that the solder has come off? Should I run a line across that?

"...I noticed something old...a stretch of solder which appears bronze in color..."

The "printing" on printed circuit boards is actually copper foil, which appears "coppery," or bronze in color. Copper is an excellent electrical conductor, accepts soldering very well, and is ductile—so is perfect for this application.

When these electronic circuits are manufactured, an automated, high-speed method is used for soldering the entire board at once (sometimes called "wave soldering" or "phase change soldering"). This in essence solders the entire board, not just the connections points. So all of the copper on the board gets a solder coating, even though it's only the electrical connections that benefit from it.

A downside of automated soldering is that the blend of metals results in a solder composition that is physically weak, crystallizes (and breaks), and is usually thin on coverage.

95% of the time you can fully recover a flaky relay by manually resoldering all the connections using a soldering iron (or gun) and good quality electronics solder, available at Radio Shack. Use an iron (25 Watts, or so) on the smaller connections and a gun (200 Watts, or so) on the heavy connections that mount the relay to the pcb, and at the spade lugs.

The pictures below illustrate an OD relay "before and after." In the top pix, cracks are visible at several connections. The bottom pix shows the same relay after resoldering.

Yet again the Brick Board has saved me some money. I resoldered the relay (tahnks for the pictures) at work today. It works like a charm. That was the best ten minutes I've spent in a while.

Good news! Now do precisely the same to your fuel pump relay. When it becomes intermittent, it leaves you 'n family stranded.

In fact, those Bosch relays are specially engineered to fail on the coldest, wettest Sunday night as far from known civilization and cell towers as possible.

Don Foster (near Cape Cod, MA)