M5OD - Rebuild or replace?

[masospaghetti]

My M5OD is finally getting too crude to shift into first gear to leave it alone, so i'm looking at repairing it. Sometimes it shifts just fine, but sometimes it'll kind of "fall" into gear while grinding, with little resistance. If i leave the clutch depressed for a couple seconds before shifting it seems better but it only happens in first gear.

First off, does this sound like a clutch hydraulic issue? The fact that it's first gear only leads me to believe not.

Otherwise, it appears my options are to rebuild it myself, or replace it myself. Rebuild kits appear to be around $200 - what would be a reputable source of these?

For replacement, www.car-part.com has M5ODs with about 100k miles for $450, and M5OD-HD's for $500 with 64k miles.

Would you trust a junkyard M5OD or HD transmission without overhauling it?

Any insight or comments are appreciated. Thanks all.

[rickybobby]

it sounds like a bad 1-2 synchro, so you dont really need the whole $200 kit. you should be able to get just the syncro kit on ebay

[IAmTodd]

I wouldn't buy a kit until you have the trans out and apart. You need to replace only what is bad. My newly acquired M5R1 has a bad fifth gear (thinking syncro). I'm opting to purchase a newer M5R1-HD as the cost to rebuild a high mileage trans is going to be the same as purchasing a new low mileage unit.

Ultimately it's your call, how experienced you are and how comfortable you are with tearing down the M5R1.

[4x4junkie]

I would think if the trans is not making any unusual noises (besides the grinding while shifting into gear), no gear whine, bearing racket, etc., a rebuild on it is probably the best plan (gear whine would indicate there is likely damage to the gears & cluster shaft, replacement is likely to be more cost-effective in such cases).

As for junkyard trannys, I would certainly pull the cover on one to inspect it, but if everything looked & felt OK, and the synchro clearances were good, I run it (infact, that's exactly what I did with the M5OD now in my BII. I think I got maybe about 8-10K on it since putting it in. JY claimed it had 123K, but I could've easily mistaken it for one having 50K, it looked pretty good inside. YMMV).