Transmission gone bad?

[freelandken]

The mechanic seems to think the transmission is shot. Will go into reverse, but not forward. Seems rather premature since the engine only has about 1500 hrs. Going to get other opinions, but in the meantime, has anyone removed/replaced/rebuilt their transmission in a 37 Tayana? Very little access to the rear of the engine and trans. I have a Perkins 4-108 and the only access to the trans is from the lazerette. Mechanic doesn't think the trans will even fit through the opening in the cockpit.
How difficult a job is it? Does the engine have to be pulled? Any first hand experience?

Little background; boat doesn't get used much. During the last hurricane in Nov, the boat pulled up it's mooring and stopped about a mile away. Had bumps and bruises along the way. When friends attempted to motor back to the mooring, they weren't getting anywhere and thought the prop was fouled. Maybe a month later, tried to motor again and again nothing. Pulled the boat and during repairs found the trans had no fluid. Filled and was able to motor back to the mooring with no problems. Then after about another month or two, tried to motor again and again trans was apparently slipping. Fluid was checked today and there was fluid. Added some to be sure but prop would only turn in reverse, not forward. There is also signs of leakage.

[brantleychuck]

What make is tranny. BW. Velvet drive?

[freelandken]

Believe it is BW.

[captstu]

Is it the tight fluid?

[freelandken]

NAPA ATF automatic trans fluid for Dextron III Mercon fluid applications. That's what was put in when empty.

[pcmm]

It won't got into forward at the pedestal or at the gearbox? Big difference I would (If you haven't done this already) disconnect the shift cable from the trans and see if you can "shift it" manually. all the shift lever does is activate a valve in the BW trans

[freelandken]

I activated it from the pedestal and the mechanic activated it from below at the trans.
I will look at your suggestion. Thanks

[pcmm]

Originally Posted by freelandken

I activated it from the pedestal and the mechanic activated it from below at the trans.
I will look at your suggestion. Thanks

The BW trans is bulletproof, totally rebuildable could be a pump issue, could have an airlock in the hydraulic lines, might not have enough oil in it.

[freelandken]

When you say "oil", do you mean trans fluid? I think that's the only thing we have right at this point, but it's good to hear possible other problems. Don't know how to check the other possibilities, but I'll try to find out. Thanks.

[pcmm]

Originally Posted by freelandken

When you say "oil", do you mean trans fluid? I think that's the only thing we have right at this point, but it's good to hear possible other problems. Don't know how to check the other possibilities, but I'll try to find out. Thanks.

yeah sorry, the ATF is what I meant. Google for the manual iif you can read the plaque on the trans. it will help a lot.

[osprey877]

To remove my Hurth transmission with my engine in I would need enough room to move the transmission aft at least 1" to disengage the shaft from the engine flywheel, and then another inch or so to clear the bell housing. Perkins owners should be able to tell you what the clearance needed is on your engine, but it is probably in the range of 2-3 inches. Moving the propeller shaft aft 2+ inches is probably doable if you don't have a shaft strut and cutless bearing, or if you do, then your shaft zincs have to be far enough forward of the cutless bearing to allow the shaft to move aft. If you have a dripless shaft seal you will need to be very careful moving the shaft that when you loosen off the forward seal, you maintain enough pressure on the rear seal to keep the water out. OTOH, if you have a long shaft and a cutless bearing, there may be enough play in the propeller shaft through hull that you can push the shaft down or to the side enough that the transmission can be pulled back.

Probably easier/safer to pull the engine forward a couple of inches. Disconnect the exhaust, raw water supply, mounting bolts and then connect a block and tackle from the mastbase to the engine and Bob's your uncle. If there is no room on your engine beds to move it aft, put a 3' length of angle iron under each side and slide it back on them.

However, I wouldn't do anything until I had emailed or phoned the mfgr'rs service department, who will likely know right away what the problem is and how best to deal with it. I have found most mfgr's service departments are very helpful and at the very least they should be able to tell whether it needs to be removed or not to diagnose the problem. Take some photos of the transmission so they will know what the model number is.
Hope that helps. Good luck.

[osprey877]

Do you have a folding/feathering prop? If so, are you sure that isn't the problem??

[osprey877]

I also assume you and your mechanic have checked the shift linkage is working properly and that the gear shift lever is not being impeded? On my boat there is very little clearance with the muffler and the shift lever can jam if the muffler is accidently shifted.

[shakey doug]

The correct way to check oil level on box is to run motor and move gear shift to fwd then rev a couple of times then shut down and immediately check level. This will give a true level when cooler and plumbing are full. When viewed from behind, the Box has a pipe fitted to the RHS fwd sump area, you will find a filter screen hiding behind the nipple often over looked at service time if this blocked it can cause your symptoms. With mounting removed the BW box can be man handled.

[oldcal46skipper]

What is the reduction? BWVD's come in 1-1, 1.5-1, 1.9-1,2.5-1, 3-1 +++

When you were running the gear with little or low ATF, you probably damaged the 13 forward gear discs. They can be replaced by a competent trained technician, but the gear box must be in the shop.

I test pressure in F-N-R with a gauge. It should be 100 to 175 PSI. You may have damaged the pump also,but new ones are available.

I have been repairing BWVD's since completing their training about 40 years ago. Bring it to me and I will test it while you watch, free. Repairs is parts + labor. I also have several BWVD's ready to go and/or will rebuild yours.

BTW, I am in Pensacola, FL by Bayou Chico. PM for details.

Tom