Transmission Noise

I have a 1998 SNOB (GT-40, PCM 1.23:1) that has a whistling/whirring sound between 2,000 and 3,100 RPM. It is loudest around 2,600 RPM. I took off the flame arrester, ran it, and the sound was still there. When I press in the button at the base of the throttle to disengage the transmission and rev the engine up to 2,600 RPM the sound is not present.   While cruising, I lifted the cover and listened back near the transmission, and the sound does seem to be the transmission. Is there a fix such as a different type or weight of transmission fluid? Or any other fix? The sound is not new and is not loud enough to be aggravating, but I wish it was not there.
I have read all the related discussion threads I could find here and elsewhere, and even posted this thread over at PN a while back. But a potential transmission remedy was not mentioned. What do you think? Any suggestions?
Thanks, Ed

TRBenj,
My ski partner has a 2000 196 with the GT-40 and has no transmission noise. [I am guessing he has the 1.23:1, but I have never looked.] The whine from the video in your link sounds similar to mine, and, as you stated, the whine is more pronounced in my boat with the GT-40. Have you heard of any way to lower/eliminate the whining sound?
Ed

I have the insulation kit from the 2003+ boats on my doghouse, which helps with the noise (you can't even tell if the blower is on) but the whine is still there.

Mine was purchased and installed by the dealer to the tune of just under 300.00. The kit alone was over 200.00 according to the invoice but this was back in 2003 so I'd give them a ring and see what it goes for. I'd imagine it quiets the whine a bit, as well as everything else. I haven't done a head-to-head comparo but I'm guessing it helps.

TRBenj wrote: M3Fan wrote: Mine was purchased and installed by the dealer to the tune of just under 300.00. The kit alone was over 200.00 according to the invoice but this was back in 2003 so I'd give them a ring and see what it goes for. I'd imagine it quiets the whine a bit, as well as everything else. I haven't done a head-to-head comparo but I'm guessing it helps. Joel, would a '98 have the same motor box as your '00? I know the '97 was different (carry over from '96). Theres nothing special about the CC kit. They just cut the foam to match the size of the panels. Overtons sells a kit that would work. McMaster also sells sound proof foam that would work. Personally, I was going to have the inside of my motorbox Line-X'd. Its supposed to work great for sound suppression.

I think the 98 is the first year for this design of the motorbox. The 97 had the carry-over clamshell from the 95 siggie and the 96 SN's which has clearance for the InvertaFlo if needed.

I'm sure there's nothing special about the foam. It tells me that the original owner spared no expense with maintenance though, which is nice know.

There is a 3 gear planetary with spur gears on them (straight cut gears) same identical noise you get when you put your older standard shift car in reverse and back up fast, they also have spur gears and they have a tedency to whine, Ive swapped very low hour planetaries with the whinig planetaries and the noise was less , the true cure would be helical cut gears in the planets. in forward on the pcm the gears on the reverse planet do turn and with no load are louder than with a load. once again poor design jmo....spur gears havnt been used in 30 years except for in the pcm

cheap to manufacture, expensive to rebuild, its pretty bad when you have to insulate an engine box to disguise noise

eric lavine wrote: come to think of it, i wonder if they were any quieter when the were running the heavier 20w?

I didnt notice any difference when I made the switch to ATF. Then again, I can barely hear the whine at all now- the exhaust drowns everything out!

no, stick with the ATF, valvoline ar high quality brand, no synthetic's,

Or get a louder exhaust..

I'll take transmission whine over the clunky operation and tremendous reverse gear whine of the trannies that they stick in the Bu's and MC's any day. I've driven dozens of modern ski boats and no trans shifts as smoothly as the PCM trans.

quinner wrote: I can't say I have ever noticed any whining from my tranny either, that or I am just used to it.

You must be used to it. Either that or youre deaf from listening to too much Kid Rock.

remember, my point of view is from rebuilding them, they are a good reliable transmission if cared for. i wouldnt pass up on the purchase of a boat if it had a PCM in it.

on the zf450 and 630 there are no planet's, no whine at all, 1 main clutch pack with reverse and forward on each side, then to gearing to the out put. niether side is considered forward because you can spin them full power for the direction you choose, if you want to put a left hand prop on the boat you can, just change the linkage, if you want a right hand engine you also can, of course you wouldnt do that, but these trannies are the reason why you no longer see right hand engines

Riley wrote: I kept getting a little water on my hand when it rubbed up against the bottom of the tranny. There is no moisture in the boat, so I'm a little worried that there could be a crack in the tranny casing. I had pumped about 40 oz of water out of the tranny.

It could be just a bad front seal (or rear) on the tranny but Eric will be able to fix that. You'll be in good hands!! Even if there is a crack, the good olt TIG welder does wonders.