Transmission Leak

[akintosyali]

I have transmission fluid dripping from the aft end of the transmission coupling where the shaft meets the coupling. It is dripping at a rate of 1/4 cup/day just sitting. There is no other place the the fluid trace is found. I also don't know when the issue started, or how much it leaks when I am running. The fluid level is at 75%, so it mush have just started. I need ideas on what seal could be the culprit and instructions on how to replace it. These are Velvet drive transmissions.

[REBrueckner]

It's the rear main seal....Probably the easiest thing to do is to get a parts diagram for the transmission....perhaps from a place where you'll be ordering the part(s).

You'll need the model number...71c, 72c, etc....

Schematics and some instructions available here:

http://www.marinepartsexpress.com/bw_sch_fs.html

(PS: I am risking the WRATH of certain elements here who strenuously object when I post internet links; But then again, who cares???)

[Genevatexan]

Acadian Marine Transmission in Broussard, La has great experience with Allisons and can provide parts.They rebuilt the Hydreco transmission pump on my port gears and were very responsive.

[yachtsmanbill]

Put an ounce of seal softener (brake fluid works too) in the gear box and it will last for quite a while. Its leaking because its gotten hard from sitting in the cold for 6 months. If its really worn out there is probably an alignment issue which will take out the back bearing as well.
Thats a $4 seal at Motion Indistries. Lock the flange then pull the big nut off in the center. I think thats torqued at 150 or 200 lbs. Get a flange puller and have at it. Youll destroy the old one removing it so try and get a part number before you start. If by chance there is a groove worn on the flange, get an undersize seal and a repair sleeve. Go ask John in the office for a quote and Ill gaurantee youll be doing that yourself.
If theres no room to get between the flanges, you might hafta pull the trans out and do it on deck. It weighs 175 lbs/ People laugh here when I post POTUSrigs to save a buck, but then, who cares! ws

[Boatsb]

Dont exaggerate Willy that transmission is only about 120 Lbs and by the way the seal is cheap it's the nylock bolt for the flange that is insane. Try to split the shaft coupling see if rotating the engine up in the rear will get you the space to pull the flange. If not and you have to remove it replace the front seal too just to be safe.

[yachtsmanbill]

Willy's ol' back said more than 120, but its TAARD ! Mine are 2.57 : 1 ; maybe a bit more for the bigger reduction gears? I dont remember Akins mount arraingement. Bubba installed Chryslers, so its a crap shoot! My MERCS are on trunnions and will swing up in the front which is what I would do fersure!
I think once he gets to that point, we can safely continue with flange locking, and nut and flange removal instructions. ws

http://i53.tinypic.com/20u96s5.jpg

Ya wouldnt believe what I do for the inglorious bas....

http://i51.tinypic.com/2cxxdeg.jpg

The nut measures 1-5/8, but I would a 1-11/16 along just in case!

http://i52.tinypic.com/55002d.jpg

Hard to read but accurate...

http://i55.tinypic.com/2uhxnuo.jpg

easier to read but a bit "cocked"

[akintosyali]

Bill,
We have the same transmission. I took the shaft coupling off. Nut on the back end is measuring 1 5/8 on mine as well.

Where do I get a 1 5/8 socket? Auto supply place? I am guessing I will need to also buy a breaker bar to loosen this nut?

In addition, I saw that when the couplings got together, there is a 0.062 inch (1.55mm) gap at the bottom. The gap is widest at the very bottom, So I will need to lift the back of the engine from the engine mounts-right?

[MikeP]

Looks like they applied for a patent. Did they ever get one? :)

[yachtsmanbill]

That socket is gonna cost you $50 and will be a 3/4 drive meaning youll need the ratchet or breaker bar or at the least, a 1/2 to 3/4 adapter. Youll nee to make a bar with 2 bolts to engage the coupling holes to lock the trans with to turn that nut.
Next, your gonna have to bolt the two halves together with a socket in between and "push" the coupling off the spline. After its off, either pop the seal out in place, or unbolt the rear bearing housing and work on deck. Youll need to make a new proper thickness gasket for assembly...
On the alignment, youll either need to drop the front or raise the back to get to ZERO, then adjust both ends equally to get to ZERO on the height, AND maintain ZERO on the sides. These arent clearances, but a DAMN GOOD measurement on the radial concentricity. When the coupling "rabbits" fit back together, you are getting close. Change the seal first, then we'll get into the alignment part in more detail... Ill almost gaurantee the other side needs alignment also! ws

http://i53.tinypic.com/1404sz.jpg

pardon the barbaric penmanship!

[yachtsmanbill]

Looks like they applied for a patent. Did they ever get one? :)

Geez at first I thought you meant Chrysler, but then it dawned on me that NEITHER are patented LOL. Is warner owned by MOPAR?? Maybe FORD??
http://www.borgwarner.com/en/Company/History/default.aspx

ws

[yachtsmanbill]

You really should do the seal now and the alignment after youre in the water for a day or two so the boat frame settles back into a running position! ws

http://www.youtube.com/watch?v=CU9mwaEtsUA

[akintosyali]

Boat has been in the water for about 10 days now, so it should be settled. Can I use a puller to pull the trans coupling off the trans?

[yachtsmanbill]

Id hesitate... if the flanges get F'd then yer F'd as well! Get the nut off first. Find a socket thats bigger than the shaft bore with a smaller socket inside of that which is smaller than the spline diameter. Put that between the two flanges and bolt together with 4 bolts. Keeping it square, tighten around and across the face with the 4 bolts and you should be able to jack it off (!). You MAY and I mean MAY need to put a little fast heat with a propane torch on the hub where it enters the seal to aid in loosening the fit.
You might want to run the blower first to be on the safe side! Is the Roamers' dock empty?? ... We are going in Sunday I hope! ws

[akintosyali]

So I bought a flange puller ($30), and a gigantic socket set (1-2" all sizes) for the exact price Bill mentioned ($50), built a bar to keep the trans coupling in place, put the 1 5/8 socket, and like Bill said, was too small, so instead put the 1 3/4 on the nut. Gave it a hard pull, and got no resistance on the ratchet. Thinking that the socket probably was not seated right, checked the nut, and the socket, and their placement, and gave it another go. And the same thing happened. I realized that the nut was loose! So instead of pulling out the flange, I tightened the nut, and placed a paper tower under it to see if that will stop the leak. Keeping my fingers crossed...

[Boatnut]

Would it be a good idea to take the flanges to a machine shop, and have them trued up. You never know who has taken them off previously, it helped me resolve a vibration problem a few years ago.

[Boatsb]

The seal is a few dollars. Change it and get a new nylock nut even if tightening ti seems to work. You already did all the heavy lifting

[akintosyali]

Well, the leak has stopped by tightening the nut. No leaks overnight! So I am thinking it was the loose nut that was the culprit. Since I didnt take the flange off, I am going to move on to adjusting the engine alignment. Like Bill suggested, (I am finding a lot of humor in confirming what Bill says!) I will lower the front side of the en gine rather than lift the back side up as the coupling is flush on top, and the gap between the couplings is at the bottom.

[yachtsmanbill]

I doubt that tightening that nut did anything for the seal... More like when you broke the couplings, the trans unit fell back onto center due to that .065 misalignment. You really ought to pull the flange, inspect the area where the seal rides, and replace the seal since youre that far along... Check the other sides' alignment also ! ws

http://i52.tinypic.com/2zoex5j.jpg

After you get the parallel down to 0-0-0-0 then check the radial for 0-0-0-0 also! Use a straight edge and a flashlight. Get yert nose down in there as closer is better! Remember a red hair is .004" and a C hair is about .006! This needs to be checked side to side and top and bottom. Once you move the engine for one, youll lose the others as well. It rarely works with a single move! Recheck after tightening down as well as that will move it also!

[akintosyali]

Bill,
So I see how I can move the engine up and down -but I dont see how I can move it side to side (?)

[yachtsmanbill]

Just by the slack on the bolts in the stringer. Side to side is usually closer because that what all the amatuers see when they pop the hatch. Loosen the bolts and give it a good kick, or use a piece of pipe. Always Tighten the bolts before you take measurements too!
Now that you grasp what I am refering to, get the parallels close and then adjust the height by all four corners either up or down, but all four equal. Guys do this on the hard, and when the boat sags from blocking, it raises hell with this stuff... ws

[akintosyali]

Bill,
The engine has a single rubber mount piece at the front, about 5.5" long, 2" wide and 1 3/8" high . It is not an adjustable piece - just a rubber block that sits between the engine block frame and a metal beam between the stringers. I took the piece out, and it basically is a rectangular engine mount, with 2 metal plates on top and the bottom, and 2 bolts that seem to go through the two plates.

So I don't have any bolts or screws that can adjust the height of the engine on the front, I have those only at the back. But since the space in the coupling is at the bottom, I need to lower the front side of the engine. How can I do that? Is there a place I can go to order a rubber block like this at a certain height? Either way, should the front side be adjustable? If so I will need to set up a bolted system, but neither engine has the front side adjustable (up or down)...

[yachtsmanbill]

Thats why I love Bubba J. Chrysler... and why they outlawed first cousin marriages. Ill be at the yard uncovering the Roamer about. Swing by for a hand, and Ill come over and have a look... ws

This should entertain you for a while... The key word here is "shims"

http://i51.tinypic.com/a5hifp.jpg

http://i51.tinypic.com/2u55qif.jpg

http://i52.tinypic.com/2ds4l50.jpg

[akintosyali]

Bill,
I am already at Belmont - would love to give you a hand whenever you need me - just call :)

Let me know if you ever come towards downtown..

I am thinking about buying this, cutting it into the right size and putting some bolts through it. You think it will work?
http://www.mcmaster.com/#neoprene-rubber/=ccjic8

[yachtsmanbill]

Dont cheap out now... ws

http://motors.shop.ebay.com/__?_from=R40&_trksid=p3841.m39.l1313&_nkw=marine%20engine%20mount&_sacat=&rvr_id=233084740416&clk_rvr_id=233084740416&MT_ID=335&crlp=7072829091_9887&tt_encode=raw&geo_id=491&keyword=marine+engine+mount&adgroup_id=1076565111

[akintosyali]

Bill,

Thanks for the link - I will check these out -- but you do realize that the I was technically not being cheap by thinking about buying material that is as expensive as these mounts?

[yachtsmanbill]

No doubt, but wait till you price new mounts... Id buy the used stuff as long as it is not all oil soaked and spongy! ws

[akintosyali]

Bill,
I purchased the marine engine mounts for 850lb engine, and have a big challenge: The old mount was 1 5/8 height. That is height from the bottom of the rubber mount to the top. The new mount, the base of it alone is 1/4 taller than the old mount.

At this point, I have few options:
1- try to find mounts with a much thinner base.
2- place these mounts under the current beam with bolts (Doesnt sound secure)
3- find another option?

[ppat324]

Akin, Bill is down at the boatyard with no phone service(damn cell towers). When i talk to him in the morning I will let him know what you posted and see what he says...the best we can do for you until Tuesday when he is home again with the Roamer! ppat