Allison trany leak on HR 37' diesel 8.3L 1995 Imperial

[bluewaveRVdp]

The previous owner had the Allison 6-speed automatic tranny fluid replaced & filters changed.
ONE of the 2 round 6-bolted covers in leaking & I need to know how much oil will be lossed when I remove this cover & replace the defective seal....  OR do I need to drain the entire tranny to do this??????

This drive train seems to be excellent, for even though it leaks (& kills the grass) I could not see change on a cold-not-running engine change on that mile long dipstick on the trip to Yuma & back to Silverdale WA.

John... checking out the RV life style...  Wanted a 37' Nordic Tug to visit the Family mining claims in SE Alaska,as we din in 1980s &1990s, but getting to old for that.

 

[RedandSilver]

I've watched some videos on changing the oil and filters on an Allison 3000 series.

They drained the main unit and then unbolted the round covers which hold filters on each one.
If I had to guess I would think a quart or more came out when they removed the filters - but that was after it was drained.


There are a couple of "O" rings and gaskets, as that round cover actually goes up into the cavity of the unit an inch or two and
the filters are attached to them (the covers) really.

Who ever changed the fluid and filters last might not have cleaned off any left over gasket material and that MIGHT be one reason
yours is leaking.  Also if one of the O Rings (which is really more square then round) got twisted when put on. that could cause a problem.

It's not rocket science - so most can do the job if they are able.  I believe it takes about 20 quarts of transmission fluid.
When you order new filters (2) they come with the gaskets and O rings as needed.

I may be changing my fluid and filters as my PO didn't give me any records of when things where changed.

So IF you don't know when yours was changed - for peace of mind I would start over and do the job right.
There are videos on YouTube that show it being done.

Hope that helps some.

 

[Utclmjmpr]

  Evan if you just remove the leaky one you will loose all the fluid in the pan, if the fluid is recent then pull the drain plug and remove the leaky one and reseal it.. If you drain into a CLEAN PAN you can reuse it with no problems.>>>Dan  ( Be carefull when replacing the six bolts on the side you removed, the proper torque is importand)

 

[8Muddypaws]

I've done filters in my MH3000 several times.  When you replace the filters the instructions that come with them specifically say how much fluid you will lose if you only remove the filters. (It depends on the pan you have). it is NOT all the fluid in the tranny.

There is no way I would ever put used fluid back into a transmission!  I'm not going to risk a $10,000 transmission to save a couple of quarts of fluid.  Transynd even at $80 a gallon is cheaper than a new tranny.

 

[aboatguy]

You won't even lose all of the fluid in the pan.  As I recall the filter kit comes with the gasket and if you change the filter without draining the pan you will lose a quart or so of transmission fluid 

 

[bluewaveRVdp]

I want to thank you all for your feed back.
I'll see/search for the seals I need unless someone knows a cost-effective place to get them.  I am finding out that a lot of places/part suppliers feel highly of their parts = prices show it.  This seems to be the same when I shop for FAA-PMA parts for my 1956 Cessna 172 & before that the power boats I had.  Thanks for the internet!!

The Tranny oil was done in 2015-August.  The pan, if one can call it that, is a casting of the housing.  There is no separate pan that I noticed.
Square sided O rings, sounds like the seals on the base of the barrels/jugs on a Lycoming or Continental aircraft engines.
Anyone have the torque for the 6 bolts.  This must be under a high pressure for those bolts to be so big & 6 of them.

 

[Gary RV_Wizard]

No, not super-high torque on the filter bolts.  38-45 lb-ft on my Allison 3000 & I think the 4000 is the same. The 1000/2000 series uses a spin-on filter, so much less torque. If you drain the tranny, the drain plug torque is only 18-24 lb-ft.

The amount of fluid depends on whether the filter is standard or high capacity, but all recent models use the high capacity filter.  Yours is older, so check the part numbers for the filter type. I think you can change to the high capacity tpe, though, and I recommend that. And install Transynd (or TES-295 compatible synthetic fluid) if that hasn't been done already.  As I recall, you lose a 2-3 quarts changing the high-capacity filters.

Allison has excellent Service Tips on their web site, and detailed info on various tranny models and parts. See http://www.allisontransmission.com/parts-service/faq-service-tips

 

[RedandSilver]

For what it's worth:

The drain plug torque is 27 ft lb.

The filter bolts torque is 32 ft lb.

These numbers I got from a video done by an Allison Tech.  He stresses how important those numbers were.
When I change my transmission oil and filters the above numbers are what I will be using.