Transmission Won't Move Boat

[Century63]

Here's the problem. I have a Borg Warner 72C behind a big block Buick. Motor starts right up. Put the trans in gear and it will move forward and reverse. Place the boat in the water and the engine strains and the boat will not move. Would there be a valve in the trans that is moving or blocking a hole for trans fluid flow when the trans is put under load. Wonder if Clint would have the answer to this one since he is knowledgeable on the damper plate, which I have had to install in the past. Any words of advice would be greatly appreciated. Century63

[lively]

have you hooked a pressure gauge to check pump pressure ?

[Century63]

Where would you hook the pressure gauge to the trans. There is two hoses. I imagine one is IN and the other OUT. Also, what should the pressure read. Thanks for the info.

[Century63]

One other thought. The boat was running perfectly when I put it away in the fall. Drove to the lake (432 miles) and dumped it in the lake. Would not move. It is like a spring or something might have snapped during the winter. Thanks again for any assist with this.

[Salty87]

you posted on the weekend and they're open now...skidim. those guys know everything.

[csuggs]

Here's the problem. I have a Borg Warner 72C behind a big block Buick. Motor starts right up. Put the trans in gear and it will move forward and reverse. Place the boat in the water and the engine strains and the boat will not move. Would there be a valve in the trans that is moving or blocking a hole for trans fluid flow when the trans is put under load. Wonder if Clint would have the answer to this one since he is knowledgeable on the damper plate, which I have had to install in the past. Any words of advice would be greatly appreciated. Century63

Not too sure about that scenario. When you say it would move forward and reverse, do you mean out of the water?

[Century63]

Yes, the boat was on the trailer and I placed the trans in forward, neutral, then reverse. The prop turned in both directions and would go faster if you revved the engine. The engine in neutral would rev real good. It is when the boat was placed in the water that the engine strained like under terrific load and the boat would not move. Thanks for any info you guys might have.

[lively]

so did the boat get off the trailer ? i mean not to be funny and all cause ive done some funny stuff myself but did you make sure it was un hooked and in deep enough
water/ramp to slide off bunks ?

pressure ports are allen heads one on reverse side and one on main body of trans ..

[Salty87]

Yes, the boat was on the trailer and I placed the trans in forward, neutral, then reverse. The prop turned in both directions and would go faster if you revved the engine. The engine in neutral would rev real good. It is when the boat was placed in the water that the engine strained like under terrific load and the boat would not move. Thanks for any info you guys might have.

you say it rev'd good in neutral. what was the engine doing while in gear? running rough, sputtering, sounded normal?

[Century63]

The engine is running normal, NO sputtering, missing or anything. If you are familiar with a tractor pull where the weight is being loaded on until the point when the load is too much and then the engine pulls down (straining). It is the same in this boat, put in in forward and the engine strains to move the load. In neutral the engine will rev to 5000. In forward gear it will not rev up but pull down. I have had the engine tuned with new everything. Even had the heads rebuilt thinking maybe a broken spring over the winter time. Any suggestions. Thanks.