Transmission Oil Dark Color

[JD5652]

Miss Maggie is a 1976 58 LRC. She has Allison Model MH30 3:1 transmissions with oil coolers.

While checking the oil level for a recent trip I noticed the oil was dark in color on my starboard side. It does not smell unusual or "burnt". It does not have a gritty feel to it. Oil drive pressure is normal at about 150 psi.

I changed the oil and filter and traveled down to Venice, FL from homeport in Palmetto this weekend. It's about a 6 hour run down the GICW. Upon arriving in Venice I checked the transmission oil and again it had turned dark in color. I monitored transmission and transmission cooler temperatures on the way down and everything is normal at about 165 deg F.

Thoughts?

 

[CGHOST4]

The rear seal on the engine is leaking engine oil into the transmission. I had the same problem years ago.

Caesar's Ghost
1980 58YF

 

[ageless]

I was going to ask if oil levels were more in gearcase after running and if engine oil was less, would explain it

 

[Sadey]

Had the same problem. Rear seal leak allowing engine oil into trans. Mechanic said it’s not a huge deal as it’s the same oil but something to be addressed in time. We did it right away. It’s a big job and costly because of the labor involved. He had to A frame the motor off the mounts to separate the housing.

 

[SEVEN]

Rear seal needs replacing. Sorry.

 

[JD5652]

Thanks for everyone's quick response! I also posted this on the LRC Club forum and got the same response.

I did check the engine and transmission levels after my 6-hour run and no significant difference in oil level in either engine or transmission.

I assume the boat has to be pulled to replace the seal as the prop shaft would have to be moved aft to separate transmission from engine?

For those that have had this done, can you provide a budgetary cost estimate or number of manhours it took to replace the seal?

Thanks!

 

[Sadey]

Ours was done in the water. The receipt is on the boat and I won't be there until next week but I'll look. It was done in Stuart Florida in 2019 so not sure how relevant it will be.

 

[Pascal]

No you should be able to do it in place. Once the shaft is disconnected it can slide back a few inches.

 

[JD5652]

Ours was done in the water. The receipt is on the boat and I won't be there until next week but I'll look. It was done in Stuart Florida in 2019 so not sure how relevant it will be.

THanks! Even if it has the number of manhours it would be helpful.

No you should be able to do it in place. Once the shaft is disconnected it can slide back a few inches.

Understood...thank!

 

[Sadey]

I'll post the all the info I have once I get to her. Should be 7-8 June.

 

[JD5652]

Just talked with Wayne of Anclote Diesel in Tarpon Springs. They are going to come take a look at my situation in the near future. He is definitely THE GUY in SWFLA for DD two-strokes BTW.

One thing he did mention is that if I'm not seeing a rise in transmission level, then it's possible the clutch plate is disintegrating as that will discolor the oil as well.

We will know in a few weeks one way or the other.

He says about a 8-hour day to block the engine and disassemble and then about the same to reinstall. The "in-between" work depends on what they find when they get it apart. He prefers to do the work in the water.

Thanks for everyone's input!

 

[rsmith]

Both my 12/71’s leaked into the trans for 20 years until I rebuilt the mains new seals stopped it didn’t cause any damage and the amount was just enough to tint the oil. I wouldn’t pull the engine apart just for that

 

[Sadey]

Sorry it took so long to reply. Looking at my receipt I was billed 40 hours for the job. I know it was a process which included assembling an A-frame in the engine room in order to lift the block to separate the bell housing from the block. Hope this helps and best of luck!