Gearbox Magnets Have No Metal Filings (magna Tp 1990), Spare gearbox at wreckers has no metal on magnets Options

[Curioso]

Hi

I went to a wreckers today and removed a decent looking gearbox for a TP Magna as a spare. Cost a bit but I'm not confident without one, because they often have problems.

As is my custom though, I removed the pan while the box was still connected to the engine, and drained the box with that as well as the plug beforehand. To my surprise however, the five(5) magnets on the pan's base had no metal filings on them at all. Usually this is a good litmus test of how worn the box's clutch plates etc are. The other thing was the oil was a healthy-looking reddish brown - I've seen much worse oil in these boxes. And there was recently applied blue sealant all over the join between the box's two hemispheres - indicating recent work. And overall the box was hardly scratched or greasy at all, which is also rare for a 21 year old box.

Could it be that these things, especially the total lack of metal filings on all five magnets, indicate a recently reconditioned box with new plates that haven't worn yet? Or, to play devil's advocate, could it be that the plates are so worn that there was no more metal filings left to be scraped from them onto the pan magnets? This last alternative would mean that someone changed the filter and pan gasket and removed the filings but didn't realise the plates were now unserviceable, hence why it ended up at the wrecker perhaps (there was no crash damaged on it, but that's not unusual).

Which do you think is the most likely scenario? A good box or bad box?

If I took a guess myself I'd say a good box that had its filter recently replaced, owing to its apparent good quality and good oil. Too many pointers to a new box for my liking here, but I'm not totally sure. It's a quandary, a riddle wrapped in an enigma (IMG:style_emoticons/default/puzzled.gif) .

Curioso

[chain rattle]

if the box has had work the magnets would be clean
take off the filter and look for metal or brown friction pad material

most good auto shops engrave a date of work or some ID of service
inside the auto pan

I would say you were lucky

try going back to the car you took it out of an look for
an auto service sticker in a door wells or under the bonnet

[Curioso]

I looked for one of those stickers on the car from a service shop and found one but it had little information on it other than the company name. It looked pretty recent though. The other thing was that the cylinder head had been removed and all the engine mounts bar the gearbox mount were also gone. So I suspected that there had been recent overhauls on the car which made it attractive to someone looking for those parts. Most of these cars (>90%) have all of that intact because no-one wants those parts when they're old and greasy.

This morning I removed the pan again, then the filter. There was no material on the filter other than two minute pieces. There were tiny almost microscopic metal shards on the magnets but so small as to almost not be there. Nothing like the huge plumes and balloons of filings I've often seen. After totally cleaning up the pan I noticed there was no engraving on it either.

Looks like it might be a good box but only installation will tell and I never install a gearbox unless I really need to - it's too much hassle for a possible loss if its got problems I can't see. If I could find an automatics shop that would disassemble it and check it for plate wear I would do that, also if they could check the cogs and compression, but I think they'd want a pretty penny for that. Last time I did that it cost me almost $90 for a condition report, but that was while it was on the vehicle. It could be more or impossible to do if it's just a freestanding part.

Curioso

[Curioso]

Checked with an automatics shop - they can't do much valuable testing unless the box is in the car. Hopefully it will get me around for a few months anyway while I recondition the other one if that starts failing and I have to swap them over.

Just a heads-up for those wanting spare gearboxes. When you're looking, find the VIN-style number stamped on the box during manufacture (i.e K751AOW5) and DO NOT deviate from that even one iota. If you install a box with even ONE DIGIT or character not exactly the same, it WILL NOT WORK (i.e. K751AOW is not compatible at all with K751AOW5 - even has different wiring). The serial number below this stamped number is different for each box though.

The second thing is plug type for the electrical connections. Some are round, some square. Always get the same type you currently have.

Other factors relevant to gearbox compatability are sedan or wagon (incompatbile boxes) and EFI or carburettor (incompatible boxes). These boxes have different electrical looms and gear ratios to the sedan/carbie version. Your ECU computer won't be able to communicate properly with them, they will go into failsafe 3rd and you will be back at square one.

Curioso