ResQme

The transmission on left (starb.) side engine keeps building pressure and blowing the main seal. My mechanic seems to think I need to replace it, which I feel he is probably correct. He mentioned buying one used, but there seems to be some places that can rebuild or sell a rebuilt at a reasonable cost. The trans. is mated to a TRS outdrive............Any thoughts as to my best course of action? Thanks

dereknkathy

there is one TRS velvet drive on ebay for 500 or make offer. says used-worked when removed. the are a zillion velvet drives on ebay 250 to 2500. but I don't think they can be used on a TRS setup. check craigslist in your area too. I think the TRS tailstock is integral to trans case. but you could use most internal parts except tailshaft-I think. blowing seal, it may just be a check valve in front pump that is stuck or something simple like that. I know it is the simplest automatic transmission ever made. it makes no diff if port or starboard. same rotation in a trs setup. even an opposite rotation velvet drive can be flipped by turning a plate around in front pump. where are you. there are a lot of TRS guys on this site. but you can't enlist help from somebody over a hundred miles or so away.

mike tkach

iTrader: (3)

resqme,left is port,a velvet drive can be totally rebuilt,it is a pretty simple job for any trans guy.i would rebuild instead of bying a used one that may have more problems than yours.

Unlimited jd

iTrader: (5)

Is your mechanic using the rubber seal that comes in the alto kit? If so that's your problem. The rubber seals only stay in sometimes with loctite.

ICDEDPPL

iTrader: (1)

The problem with the early transmissions is the Velvet.. it doesn`t hold up very well in a wet environment but it is beautiful... later they switched to a metal case and most of those issues were eliminated.

http://www.youtube.com/watch?v=w-eb61BLIWw

motor

iTrader: (3)

I've bought genuine bw parts from here http://www.marinegears.com/ They also will rebuild yours

MILD THUNDER

iTrader: (3)

Yes. My buddy who rebuilds marine transmissions had that issue.

Also, I believe if the front pump is worn, you may get pressure blowing against the seal.

Mbam

Yes a worn pump will do that, actually a new pump will sometimes do it.

We use a hi-temp superglue on our seals. And more importantly we also figured out a mod to the pump to relieve the pressure. The newest pumps direct from Velvet Drive are machined with a lip to retain the seal but they didn't do anything to relieve the pressure. So some of them will build up so much pressure that the seal gets a hemorrhoid.

Falcon

Check runout (tir) between the crankshaft and the flywheel housing bore. High runout (over .007" if I remember right) can cause issues with the front needle bearing and the pump.

Mbam

Yes, that too - good catch
Also need to check the runout on the drive plate.

The truth is no one checks this stuff. We have it in our instructions but I doubt if anyone reads them.