97 SN 196 Leaky Transmission

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   Hey all,
Toward the end of last summer our 97 Nautique began leaking transmission fluid into the bilge.  The leak seemed to be below the bell housing, so given 25 years and 890 hours, I was suspecting I might have a leak in the transmission pump front cover seal.  

This past weekend I removed the transmission from the bell housing.  I was surprised to NOT find transmission fluid inside the bell housing and the area around the seal did not indicate an obvious leak.  I did notice that there was transmission fluid dripping from the lower mounting bolt holes.  I cleaned the area and after sitting awhile, fresh drips of fluid had appeared  (see image with arrows)

My best guess is that the gasket between the adapter housing and transmission housing is leaking.  Has anyone experienced a similar problem?  I see Nautiqueparts.com and SKIDIM.com sell an overhaul gasket kit but does anyone know if the gasket can be purchased separately?  The transmission was working fine - other than the leak.

Thanks,
Phil

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70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Topic: 97 SN 196 Leaky Transmission Posted: February-28-2022 at 6:21pm
	Hey all, Toward the end of last summer our 97 Nautique began leaking transmission fluid into the bilge. The leak seemed to be below the bell housing, so given 25 years and 890 hours, I was suspecting I might have a leak in the transmission pump front cover seal. This past weekend I removed the transmission from the bell housing. I was surprised to NOT find transmission fluid inside the bell housing and the area around the seal did not indicate an obvious leak. I did notice that there was transmission fluid dripping from the lower mounting bolt holes. I cleaned the area and after sitting awhile, fresh drips of fluid had appeared (see image with arrows) My best guess is that the gasket between the adapter housing and transmission housing is leaking. Has anyone experienced a similar problem? I see Nautiqueparts.com and SKIDIM.com sell an overhaul gasket kit but does anyone know if the gasket can be purchased separately? The transmission was working fine - other than the leak. Thanks, Phil

KENO Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10643	Post Options Post Reply Quote KENO Report Post Thanks(0) Quote Reply Posted: February-28-2022 at 6:55pm
	Here's a link to a recent thread by Gary S He has a v drive with a PCM 40i as compared to your direct drive with a PCM 40A, but the casing gasket is the same, so you'll get some good info from the thread link

70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Posted: February-28-2022 at 9:02pm
	Thanks! I missed that thread when I was searching the forum. The symptoms seem similar, so hopefully I don't run into anything worse.

70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Posted: March-06-2022 at 10:40am
	Update: The folks at Discount Inboard Marine really helped me out. I described the situation and Vince said I could save some money by ordering the adapter housing to case gasket individually. Parts have already arrived. Similar to Gary, I'm planning to also replace the front seal and a few o rings. I'd recommend watching the transmission removal video from SKIDIM.com. Since I plan to do an alignment, I first removed the transmission mount to stringer bolts and raised the transmission slightly before removing the transmission mounts from the transmission to prevent any binding. Looking for advice: should I remove the pump cover and pump before separating the adapter housing and case, or should I leave them in place, change the adapter to case gasket, then replace the input seal on the pump (is the latter even possible)? Thanks.

70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Posted: March-17-2022 at 2:49pm
	Adapter plate and housing have been separated. I've emptied the bottom of the trans case and cleaned it and the magnet. The input shaft came out with the adapter plate but I was able to easily remove it. Now I'm in the process of reassembly trying to line up the teeth on the input shaft (see arrow) with the teeth in the clutch plates in the trans housing (I believe there are 5 that need to be perfectly lined up to accept the shaft). Anyone have suggestions or does it just take some wiggling to get the shaft to drop into place? Thanks!

KENO Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10643	Post Options Post Reply Quote KENO Report Post Thanks(0) Quote Reply Posted: March-17-2022 at 6:29pm
	A little wigglin' and jigglin' and some patience should get you there, one plate at a time. Standing it on end might help too.

70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Posted: March-20-2022 at 9:00am
	Thanks. As suggested, I set the trans on end, resting on the rear flange with a wood block providing some extra support. I lined up the teeth in the clutch plates the best I could and squirted them liberally with transmission fluid which seemed to help. Some things to watch out for: There is a small steel ball that is used to key the oil pump gear to the shaft. I assumed this was securely set in the shaft, but it popped out while I was separating the adapter plate from the housing, and I nearly lost it. Try to remove it after you remove the gear, or at least make sure you're working over a tub or pan to catch any stray parts. Also, Vince at SKIDim reminded me to apply a layer of tape over the input shaft splines when installing the pump cover to avoid damaging the seal.

70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Posted: May-23-2022 at 10:33am
	Just a quick follow up on this topic: Transmission leak repair is a success. Thanks Ken, Gary and also Vince at skidim.com for the assistance. Stating the obvious: if you have the transmission removed, take the mounts to a work bench, make sure you can back off the lock nut, and spray the threads with penetrating oil. After reassembly, I checked the coupler alignment and it was out by .005. A hammer and my special pry bar / screw driver came in handy to loosen and then tighten the lock nuts on the rear mounts. As the mounts were adjusted (for up and down) and a slight tap with a rubber mallet (for side to side with pinch bolts backed off) I was able to improve alignment so the .020 feeler gauge was snug all the way around the coupler. I thought the boat ran smooth before the leak repair, but seems even better after the alignment. After a test run, I changed the engine oil and filter, replaced the spark plugs and thoroughly cleaned the bilge. Next project: New plug wires, cap and rotor.

Gary S Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096	Post Options Post Reply Quote Gary S Report Post Thanks(0) Quote Reply Posted: May-23-2022 at 6:28pm
	Great to hear Phil. Sounds like your next projects will be alot easier! When you got the gasket out did you see any damage to it? Mine looked like new yet. I wonder if it shrinks and or the bolts relax to let it leak?
	69 Mustang HM SS 95 Nautique Super Sport

70CC Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: June-12-2006 Location: United States Status: Offline Points: 338	Post Options Post Reply Quote 70CC Report Post Thanks(0) Quote Reply Posted: May-23-2022 at 10:43pm
	The gasket came out in one piece but brittle compared to the new one, so heat and age likely took their toll.

97 SN 196 Leaky Transmission

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