740 Allison blowing spin-on filter seal

Grit160 · March 21, 2022, 01:17:20 PM

The search function doesn't seem to work for me BTW.
HT740 Allison in 95 Silver Eagle.
I replaced the canister filter to a spin-on OB1313 base and Wix 51861 filter. A few days ago I drove it out to town for inspection and had no issues, but today the filter seal blew before I got out of the driveway!?? I tightened it 1/2 turn as the filter shows. Also used the wide seal as required by the base. The filter specs show that it flows 28-30GPM, but I can't find anything in my Allison book on filter requirements. The book shows top fitting of trans going to filter, then from filter to bottom fitting on trans, which is how I plumbed it to flow. Any idea what caused it??

chessie4905 · March 21, 2022, 03:16:28 PM

maybe 3/4 turn instead.

Bill Gerrie · March 21, 2022, 05:34:04 PM

I had the exact same thing happen on my V730. The pressure was too great for the filter so I had to go to hydraulic filter. Never any issues since.

Grit160 · March 21, 2022, 06:22:30 PM

Quote from: Bill Gerrie on March 21, 2022, 05:34:04 PM
I had the exact same thing happen on my V730. The pressure was too great for the filter so I had to go to hydraulic filter. Never any issues since.

This is actually a hydraulic filter. I'm confused and frustrated with this thing. What base and filter are everyone else using??

Bill Gerrie · March 21, 2022, 06:56:46 PM

Could it be you got a defective filter. The filter base is the same as most use. Maybe the sealing ring wasn't fully seated in the groove in the filter.

Grit160 · March 21, 2022, 07:08:02 PM

Quote from: Bill Gerrie on March 21, 2022, 06:56:46 PM
Could it be you got a defective filter. The filter base is the same as most use. Maybe the sealing ring wasn't fully seated in the groove in the filter.

Been sitting here researching it and I think the Baldwin BT388 filter comes with a special gasket (G286-C) as recommended by Baldwin for this base. Looks like it's tapered instead of flat like the one that came with the WIX filter I'm using. Guess I'll be calling around for one tomorrow.

Tedsoldbus · March 22, 2022, 10:02:50 AM

I have an HT 740 and 6V92
Call Luke at US Coach. He sent me spin on housing and filter because my bolt on leaked every other trip. The new housing bolted on exactly where the old one was. But because it is me, the in/out flow was the opposite of the bolt on housing. My hoses were new a year ago, so we ran it up the street to a machine shop that put a 90 on the far end of the housing so the hose would reach. Took a test drive, and then just took it to Fla and back. No issues. No leaks. Yeah!
I crawled under there to try to read the filter number for you, but Luke has a bunch of the housings and filters on hand. He can at least tell you what filter. I just ordered air filters and another trani filter from him.
Luke @ US coach 888 262 2434
Best of luck

luvrbus · March 22, 2022, 11:26:11 AM

The 740 used a Wix 51623 filter with a Wix 24763 base check the base the numbers could have changed

robertglines1 · March 22, 2022, 02:13:37 PM

after you shut down do you hear bubbling in trans oil pan?? you have a air line going to a valve on side of trans... sometimes they go bad and leak air thru the assembly into trans. pressure rising the trans. About the size of a vac modulator Does not work the same.!! Then oil will go out path of least resistance--oil stick--weak gasket.

luvrbus · March 22, 2022, 03:51:57 PM

Filters are made to withstand over 300lbs of pressure,I think he has the wrong filter for the base

chessie4905 · March 22, 2022, 04:05:11 PM

Either that or it needs tighter.

lovetofix · March 22, 2022, 09:00:40 PM

Since it is a new filter base I doubt this is the problem but have to ask. Is there any way there was an o-ring on the filter base before you spun the filter on?
If an old seal sticks to the base and you end up with two o-rings it will blow out with very little pressure.

6805eagleguy · March 24, 2022, 05:00:12 PM

I remember reading a crazy story from Dave galey about that exact problem. Seems like he put a hose clamp on it to keep seal from blowing out lol

Grit160 · April 26, 2022, 05:31:38 PM

I've not been able to respond to this post for some reason?

Thanks for all the replies. Using the molded gasket with a lip fitted inside the filter fixed the problem (see pic). Baldwin gasket #G286-C works on filters Baldwin BT388, WIX 51861 & Fleetguard HF6136 with the OB1313 base. Hope this helps someone else in the future.

Boomer · April 28, 2022, 07:47:47 PM

Were you in reverse when it blew? 740s put out more pressure in reverse, like Cliff said around 300# or more. I blew a Luberfiner filter on a 740 behind a 6V92 a few years ago on a Vogue I owned for a few months. Never did like Luberfiner filters but it was on the rig when I bought it with only about 500 miles on it. Just wrote it off to a bad filter. That was a first for me but it's not unheard of.