Hard Shifting

R

rsecret

New Member
Mar 28, 2010
6
Lake Erie
Boat Info
1994 330 Sea Ray Express
Engines
454 Mercruiser Straight Inboards
I have a 1994 330 Express with 7.4s and Hurth transmssions straight inboards. Can anyone tell me why my starboard drive shifts hard into forward from neutral? Both engines idle the same which are about 650 rpm.
 
remove the cables at the transmissions and move back and forth with boat off obviously. and compare which one is tighter, this will tell you if its in the trans or the cables or the shifters, the valves at times will gall because its an aluminim control valve
 
Thanks for your reply,
It does not take more force to engage into forward but when I shift into forward it seems to engage hard like if your RPM was to high.
 
engine rpm could be the issue, no accumulator valves to cushion shifting it may vary from transmission to transmission. is there anything else you can tell me? has it always done this? more history will help
Eric
 
Hi Eric,
It just start doing this at the end of last summer. Both engines idle at 650 rpm and I did not have any transmission work done. Oil is up to proper levels and no leaks anywhere. This has been a great boat for me and never had any problems with her. I make sure all maintenance is performed properly and take very good care of her. I dont run her hard and never shift unless rpm's are at idle.
Thanks for replying back to me, I am new to this site and appreciateany info you can get me.
 
normally, the one that shifts lazily are the ones that have the problems.
internal leaks inside the trans, bad pump and to the likes will cause a lazy shift because the volume of oil is not there to apply the pack and this may be sesitive to engine RPM, imagine a pool with a 10" hole at the bottem and your filling the pool with a 15" hose, the 15 inch hose will overcome and cause the pool to spill out. now if that hose was a 8" hose the the pool would never fill because the leak is larger than the volume of water going in. thats basically transmission theory....but normally a fast re-acting, hard shift is a better sign than a slow lazy shift. if you feel you have more of a problem than i just explained please post...but chances are what you experiencing is pretty much normal
 
I want to thank you for time and advice. I will be putting her in the water in 3-4 weeks and will check it out then.

Thanks for everything,
 
stuckinforward said:
normally, the one that shifts lazily are the ones that have the problems.
internal leaks inside the trans, bad pump and to the likes will cause a lazy shift because the volume of oil is not there to apply the pack and this may be sesitive to engine RPM, imagine a pool with a 10" hole at the bottem and your filling the pool with a 15" hose, the 15 inch hose will overcome and cause the pool to spill out. now if that hose was a 8" hose the the pool would never fill because the leak is larger than the volume of water going in. thats basically transmission theory....but normally a fast re-acting, hard shift is a better sign than a slow lazy shift. if you feel you have more of a problem than i just explained please post...but chances are what you experiencing is pretty much normal
Click to expand...

Don't want hijack the thread... BUT... I have a lazy shift type problem. Usually after the boat sits all week the port transmission won't shift. After the boat has idled high for a few minutes it will shift and I did not have any shift issues the rest of the time using the boat.

So I expect that I have a pending issue with that transmission. Fluid levels are fine... What else can I look at to get a feel for what might be happening?

Thanks!
 
the true way to check these transmissions is with a pressure gauge, depending on the trans you need a manual to figure out which port will have charge pressure, rule of thumb though usually is if its lazy in both directions it is normally a pump or valve problem, if it is lazy in just one direction such as forward then you have a problem in that circuit, if you have twins test the good trans and compare to the lazy trans. if you feel testing the trans is beyongd your skill level i couild walk you thru it, more info would be needed. a sure sign besides lazy shifts is a forward drag indicating warped forward plates. please post more history
 
I do a ton of those 630's and they are pretty stout, be careful on who you bring on the boat because transmissions are easy money makers, i did one that had galled cast iron rings that would not seal, it was an easy fix...but that could get out of hand, in the wrong hands
 
stuckinforward said:
the true way to check these transmissions is with a pressure gauge, depending on the trans you need a manual to figure out which port will have charge pressure, rule of thumb though usually is if its lazy in both directions it is normally a pump or valve problem, if it is lazy in just one direction such as forward then you have a problem in that circuit, if you have twins test the good trans and compare to the lazy trans. if you feel testing the trans is beyongd your skill level i couild walk you thru it, more info would be needed. a sure sign besides lazy shifts is a forward drag indicating warped forward plates. please post more history
Click to expand...

Thank you for the feedback. You gave me some good points to investigate. It is lazy in both directions and I don't think it is an adjustment issue on the linkage.

Don't have much history to share only been on the boat 1 season and its done it from the start.

They are some pretty salty pieces the transmissions. I was down there in the ER working on the water pump last season and was amazed at how solid they are.

I know it can get expensive fast chasing down an intermittent issue so I will have to be careful how I pursue this. Boat is set to launch next week so we shall see how it goes.

Thanks again for the feedback!!
 
no 2 transmissions act the same, keep an eye on it, count how many seconds between shifts, and you may not even have a problem, if the pressure is within spec then really the pac shouldnt slip unless at one time they were low on oil and on power up they slipped and glazed the plates and if that is the case the plates lose thier ability to clamp and hold. a good rule of thumb is 3 seconds between shifts and remember a damper plate will aggravate or soften shifts to...so as you said, be careful diagnosing, you may not have a problem at all
 
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