My question is, How do u identify a trs drives rotation as being left or right??? I have heard there is no such thing as a trs left or right rotation for the out drive unit. Meaning a trs replacement is not related to the units rotaion. The rotation of a trs is controled by engine/trans and prop. Are these trs drives all the same? In my research I can not find an answer.
max

Trs drives are RH or LH Specific.The gear that is on the prop shaft sits in front of the verticle shaft on a LH and behind the Verticle shaft on a RH.The only real differance is the propshaft.
A LH Drive will have a Letter L stamped on the end of the Prop shaft where the prop nut goes.

What he said. Do not try to control the rotation with the tranny. You will smoke it. The drives are specific.

Also the uppers are the same and rotation is determined by the lower.

Yup uppers, trannies, are all the same. Lowers is were they make the change.

and LH is stronger than RH due to gear placement and support.

I always heard the RH drives were stronger than the LH. In the LH the drive shaft is end to end turning the prop shaft which would create more bind on the propeller end,more twisting load. RH turns the prop shaft from the center of the shaft so the support is evened out on both ends of the propeller shaft.

CORRECT

If u turn the inputshaft(YOKE) and the propshaft spins the same u have a LH if the propshaft turns the opisit then its a RH !!!!!

Yes, it is a 1978/ 20 footer with a stroked small block, 383 with all the goodies, hits 70 plus. Purchased as a project and re-powered it, drive got stolen last summer and i replaced this summer. This was a 3 year project , was an interesting learning curve and its a hit on the lake being piloted by a women. lol.
Also the answers I got here were very helpful in buying a replacement that worked. I thank everyone who posted on this topic.
maxine

http://images.ibsrv.net/ibsrv/res/sr...coolcowboy.gif