TRANS QUESTION

malone145 · Post by **malone145** » Thu May 31, 2007 7:31 am

Just brought our new Bertram sportfish over yesterday and as we were nearing its new home, we noticed an unusual sound. We pulled the engine covers back and the port engine transmission was smoking hot. We shut it down of course, and cranked it up again at the slip to back it in, only it had no reverse. We got it in the slip and checked the fluid level. Bone dry and no fluid in bilge. Filled up with fluid again, but still no reverse. The engines are 3208 cats and the boat is a 79. Anyone know why there would be forward gears and no reverse?

sbeer · Post by **sbeer** » Thu May 31, 2007 9:38 am

What kind of trans are they? Do they go in and out of gear [forward]. You might have pumped the oil out of the trans cooler, bad coil. Notice any white specs in the water exhaust? Mike

malone145 · Post by **malone145** » Thu May 31, 2007 10:50 am

We didn't have much time to fool with it last nite, but I do know that it doesn't slip in and out of gear. Forward seems to be just fine. Reverse doesn't engage at all. Headed to the marina after work today to see what I can come up with. It's a twin disc trans. not sure of model.

Post by **dougl33** » Thu May 31, 2007 11:14 am

They're probably MG502's with a 1.54:1 ratio. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

billb · Post by **billb** » Fri Jun 01, 2007 2:08 am

If it was smoking out of the breather like mine did when one of my cooler lines fittings started leaking,it's toast....how does the fluid smell?? twin disc 502's are very good and take a lot of abuse, but when you say it was bone dry, thats it...if you take it out this weekend, be careful because you'll probably loose forward...mine cost me 1000 to rebuild and 300 to R&R the gear....

franklyprice · Post by **franklyprice** » Fri Jun 01, 2007 2:25 am

I would say it's cooked and the smart thing to do is pull it and have it rebuilt. Even if you do get reverse to work, you'll never trust it. I would change the coolers on both gears as a matter of course, since that would be the most likely place for the oil to have gone.

mak6190 · Post by **mak6190** » Fri Jun 01, 2007 5:14 am

I know you fried the discs inside the tranny. If its making a noise then there might be some other damage inside. My tranny acted the same, forward, no neutral or reverse. If you try to force it by reving the engine and shifting into reverse you will snap the shaft inside the MG502. I had someone remove the transmission, then got a mechanic to take it apart and rebuild. I had to buy new disc and seals, all gears were in good shape. The cause of the leak was still there after the repair. You most likely have a leak in the transmission oil cooler (sits right below the turbo with an in and an out high pressure hoses). You can tell if its leaking by looking into the exhaust as it hits the water you will see little rainbow droplets. These oil coolers have very confined saltwater passages that can clog with small objects that make it though the engine sea strainers and they will lodge inside the cooler filaments creating obstruction causing small temp. rise in the engine. There is also a small anode that screws into the bottom of the cooler that should be replaced about every 3 -6 months depending on the electrolisis that you may have. I bought original CAT parts and they ran around 1300$ , PANTROPIC in Miami , FL. These are my gear box specs:- CAT Model Number 34800 Part Number 3N4601 Serial 709282 These are the parts and their part numbers I purchased CAT OEM 3N4977 PALTE 18 3N4981 Ring 2 3N4965 Seal 1 3N4987 Seal 1 3N4975 PLATE 4 3N4976 PLATE 16 3N4978 PLATE 2 You might be able to find much cheaper parts ( 400-500$), but we all know that if they are original Cat parts they should last forever. Hope this helps... Regards, Mike Kohlhofer