Just got finished replacing the O/D Solenoid in my '89 740 Turbo. No change, still can't go faster than 52mph or it will go to 3K rpm's. Checked the relay (#12), and it is intact. What now? Replace the Trans. fluid filter?
UPDATE 10-12-05: Halfway in to work today, the top gear kicked in! It works! Now all I need are new rear tires and the light on the dash tells me I've got a bulb out somewhere...
Boy, were you ever right! It didn't work on the way home from the office on the 12th, and it hasn't worked at all this morning, both on the 45-minute drive to drop my dog off at the Vet, and then another
45-minutes to my office. Grr...Thanks for the tip, I'll look at that relay.
Pull it out and pop the cover off it, look on the bottom of the circuit board, you'll almost certainly see obvious cracking in the soldering where the socket pins attach.
I'm looking at the circuit board now, it's green and nothing like the orange ones I've seen posted on brickboard where they illustrate how they resoldered the joints. Most of the trails on there seem to be under the green layer and not accessible on the top. (Excuse my non-techie jargon, I'm new to the DIY car repair world but I'm really enjoying it!) Hubby looked at the circuit board and didn't notice anything out of the ordinary either. Do we just plop some more solder on top of what's there and hope for the best?
The green coating over the traces is called a solder mask, it prevents solder from going all over the place and keeps it right on the joints. Soldering takes some practice to do well but it's not too hard. You want to heat up the joint with the tip of the soldering iron until the existing solder liquifies, then feed in a bit of fresh solder, but not so much that it makes a big ball. If it gets out of control there's a few tricks you can use to remove the solder from a joint and start over.
Oh, make sure you use rosin core solder, the acid core stuff for plumbing will ruin it.
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