Slant Six Forum
https://www.slantsix.org/forum/

A-904 case compatability
https://www.slantsix.org/forum/viewtopic.php?t=58844		 Page 1 of 2
Author:  Ed Mullen [ Mon Dec 21, 2015 5:24 am ]
Post subject:  A-904 case compatability
I accidentally bought a low position starter used trans to replace my electric TCLU unit in my 87 van.
I had it stripped of all bracketry, levers and tubing, fit with hose barb fittings and the van's shift and TV levers, installed a new gasket and filter, and had it on a jack 2" from the engine before noticing the wrong starter location.
(yeah I know: bring the old one to the junkyard, or minimally, put them side by side at home before proceeding further--I knew better at 15.)
That junkyard is 10 miles away. The next closest hit on car-part.com is an hour away in PA. (iirc there is also one in Queens, but that means either driving through Manhattan, or Staten Island and Brooklyn--may as well be in Yemen).
The one in PA has no TC.
When I was first considering rebuilding the original, a member (thanks Doug D) said they had a non-lockup TC (which I could not use on the TCLU unit).
Is it possible to install the low starter non lockup internals in the high starter ETCLU case?
Externally, it appears the difference is a pipe plug in the solenoid hole.
Assuming this could be done, could I leave the subassemblies intact, and get by with a gasket/reseal kit?
Please advise.
Author:  Reed [ Mon Dec 21, 2015 7:41 am ]
Post subject: 
Ed- could you post pictures of the electronic lockup transmission? This is a somewhat rare 1987-only transmission that wasn't even put in all 1987 vehicles.

All the internals from the low starter mount 904 case *should* be swappable into the ELC 1987 case, save for possibly the rear band. I am assuming the low starter case cam out of a pre-1979 truck. Sometime in the late 70s the 904 switched from a single to a double wrap rear band in the transmission. This require a minor change in the case construction for the rear band mount. As long as you match the rear band to the case, you should be fine.

Your 1987 transmission should have a four planetary gears as well as a wide-ratio gear set. These are both desirable, especially if your vehicle is a 1987 truck or van. In fact, chances are that the 1987 transmission actually has ore front and rear clutches than the low-mount starter. Years ago I went on a transmission rebuilding and upgrading spree and rebuilt three 904s- one for my brother's van, one for my brother's Duster, and one to have as a spare that is still lurking under my workbench.

I rebuilt a 1979 lockup trans stock, a 1973 non-lockup trans upgraded with 1968 v-8 904 guts, and a 1983 transmission upgraded with a shift kit. I discovered that the 1983 slant wide-ratio transmission had the same or more number of clutches as the 1968 318 904 transmission and that the wide ratio gear set used a four planetary gears just like the 1968 v-8 904, but that the 1983 planetary shell was cheaper looking stamped steel piece that was welded together whereas the 1968 shell looked a bit more sturdy.

I guess all this is my way of saying that you should possibly not get rid of all of the 1987 internals. If your goal is to get rid of the electronic lockup, I have to ask why. Have you removed the computer that controls it? If not, you may have problems with the computer if it is looking for a signal telling it the trans is locked up. If so, then the lockup feature is already disabled and you may be able to rename it using a manual toggle switch. Alternatively, you may be able to get away with nothing but a torque converter and valve body swap. The rest of the internals on the 1987 transmission may be superior for your application to the low-mount starter 904.
Author:  Ed Mullen [ Mon Dec 21, 2015 10:25 am ]
Post subject: 
The decision to go with a non-lockup TC was one of availability.

By my search on car-part.com, there were only two /6 A-904s available anywhere remotely near me, and neither were lockup.

I did an HEI swap, but had already designed, but not yet built, a controller utilizing a relay in place of the TCLU relay the computer controlled on the engine harness, and cut in another latching relay with an illuminated momentary contact switch on the dash (push it, it latches and lights up--hit the brakes, it unlatches and light goes off).

The decision to lose the TCLU was for time. (I could grab a local trans, toss it in, and be back on the road the same day. I could rebuild the other transmission at my leisure--it did not work out that way)

The low-mount transmission says "83," or "1983," or something that led me to believe it was an '83. The truck it came from was supposedly an '87.

A broken up phone conversation with the yard minutes ago suggests that what they gave me is not for a /6.

With any luck, the unit listed on car-part.com is still sitting there, and I can grab it on Thursday when I am off, and they are open.

Otherwise, I guess I will return the one I have this Thursday, and head out to PA on New Years Eve to grab TC-less one (if it actually exists), and get that TC from DD in the meantime.

Thanks for all the info. Good to know. (leaves me more inclined to ultimately hang on to the original trans for re-installation in the future )

I posted elsewhere looking for an online source for TCs. Any suggestions?

I will post pics, and possibly document autopsy/rebuild of the 87 ETCLU unit.

Thanks again.
Author:  Charrlie_S [ Mon Dec 21, 2015 11:03 am ]
Post subject: 
I am not aware of any low mount starter slant six 904 trans. Can any one clarify? The only low mount automatics for the slant were the smallblock 727's with the adapter plate (as far as I know).
Author:  Joshie225 [ Mon Dec 21, 2015 2:23 pm ]
Post subject: 
I firmly believe Ed was sold a V8 transmission.
Author:  Reed [ Mon Dec 21, 2015 3:11 pm ]
Post subject: 
I know petty much nothing about the low-mount starter applications, so I can't say. I only ever heard of them in trucks, and usually early 70s or 60s trucks, at that. But internally, a 904 is a 904, with a few variations to be aware of (67/68 spline count change on the input shaft, lockup valve body converter and input shaft starting in 79, rear band mount change in the late 70s, slant six applications having lighter duty internals in the clutch count and planetary construction).

If it IS a v-8 trans, the guts should still swap straight into the 87 case, so long as it is a 904. However, I say return it and use the refunded money to buy a rebuild kit from http://www.makcotransmissionparts.com/A904.html

If you can build a special electronic control to run the lockup feature, then you can rebuild a transmission. Heck, I am a lawyer and I taught myself how to rebuild 904s. They really are a beautifully simple yet rugged design.
Author:  Ed Mullen [ Tue Dec 22, 2015 10:05 am ]
Post subject: 
Quote:
I firmly believe Ed was sold a V8 transmission.
Looking that way, yes. I thought the high/low starter thing was year-based, and nothing 80's would have it. The unit they had was supposed to be for a "3.7L" (per car-part.com) from the 80's, so I was doubting my recollection (and kicking myself for not matching them up side by side, trusting my memory etc).

Hopefully the guys at the junkyard just pulled the wrong unit off the shelf, and the correctly advertised one is still there.
Quote:
If you can build a special electronic control to run the lockup feature, then you can rebuild a transmission.
It was always my intention to rebuild the ELCU trans, I just didn't plan on using it. (I was going to rebuild it for practice and to be sure I have/make the tools and jigs required to work on other A-904s, then sell it without a TC on craigslist.)

My "special electronic control" is just a pair of relays. I'm sure there is a fair size ability delta between that and rebuilding any transmission, but from what I have read and seen, the A-904 rebuild does not seem outside of my capabilities.

I think overall costs-wise, and considering local availability, I am better off with the more available non-lockup with cheaper converter, and no $80 solenoid.

It generally goes to the Home Depot, train station and junkyard. It doesn't see enough highway miles to sweat fuel economy.

In the short term, I just need to toss in whatever is available and drive it (our family car is also having transmission problems of an electronic nature, and my wife's Valiant is off the road for the winter, so I need the van for groceries and parts store runs, ASAP).

Of course if nobody reasonably local can sell me the right one, then I have little choice than to rebuild the one I have.

Thanks everyone.
Author:  Joshie225 [ Tue Dec 22, 2015 10:31 am ]
Post subject: 
All slant six automatics that did not use the adapter plate are high starter position.
Author:  Reed [ Tue Dec 22, 2015 11:17 am ]
Post subject: 
Quote:
All slant six automatics that did not use the adapter plate are high starter position.


:!: :D Thanks Josh! That is good to know. In all my years of playing with slant sixes, I have never seen a low mount starter in person. I have read posts from people that had them, usually in a manual transmission truck application. I never new the criteria for when the low-mount starter was used.
Author:  Ed Mullen [ Fri Dec 25, 2015 12:48 pm ]
Post subject: 
The junkyard acknowledged they mislabeled the transmission.

They told me they were getting one from another yard yesterday.

I drove out to get to the yard 10 minutes before they were to close for Christmas eve.

I waited 40 minutes for one of their drivers to return with the 'correct' unit.

When he arrived, I checked the bellhousing, was reasonably satisfied it was for a /6,

In a hurry to get the car back to my wife, I exchanged units with the driver, and left.

Upon setting on the ground I realized it was a long tailshaft version,

I started disassembly to swap tailshafts and housings, and realized it is not an A-904,

I'm guessing it is an A-727.

Is there any demand for a long tail /6 A-727? (I'm sure if I return it, it will just eventually get scrapped after they attempt to sell it for the wrong application a few more times--I'd hate for that to happen, if somebody can use it).

I think I have to just give in to rebuilding the ETCLU.

When it failed, the TC screws came loose and fluid dumped from the bellhousing.

The fluid was pink and foamy (slightly brown) and full of clutch material dust. Magnet had some metal filings on it.

Any chance the TC is reusable?
Author:  Reed [ Fri Dec 25, 2015 5:22 pm ]
Post subject: 
I wouldn't risk reusing it. You can get new ones pretty cheap (like $80 at makco) and it isn't worth another failure (at best) or contamination of a freshly rebuilt trans and then failure (at worst). The 727 is super heavy duty and non-lockup and will require shortening the driveshaft and getting a different front driveshaft yoke to wrk on your van.

I am sure you can find a slant racer who would take a 727 off your hands.

You can also swap the tailshaft and output safe to a short version if you find one from a car application (even V-8 ones will work).
Author:  Ed Mullen [ Mon Dec 28, 2015 10:07 am ]
Post subject: 
Well I returned the A-727.

They said they did have the correct unit at another yard (where they had sent the driver Christmas Eve, and he grabbed the wrong one--supposedly).

They are to have it tomorrow (I will ask that they deliver it, as I have already made four trips, lugging two wrong transmissions back and forth).

I'll see what I get this time.

I am going to step up my efforts to rebuild the ETCLU unit sooner, rather than later, but am still going to toss in a junkyard one in the meantime.

I could not find a lockup unit for a 6cyl on Makco, and the cheapest non-6cyl LU was $116 (most being over $200). Napa has one (new) for $150, so I am not too worried.

(BTW: I had been calling the ETCLU unit 'original' but upon closer inspection, it has a lot of welded lettering suggesting junkyard or rebuild shop bin. I know my dad had it rebuilt once. I used to have the receipt, but have since lost track of it. I wonder if they just tossed in one off the shelf, and took the original for a core. I had it rebuilt years ago, but I know what they had taken out went back in.)

Thanks for the input.
Author:  Reed [ Mon Dec 28, 2015 10:15 am ]
Post subject: 
Lockup torque converters on Makco for the 904:

http://www.makcotransmissionparts.com/A904tcLU.html

more specifically,

http://www.makcotransmissionparts.com/TC-CR9H.html

I may be remembering prices from many years ago as it has been a while since I had to get a new torque converter. Prices are likely a bit higher. Looks like Makco wants $116.63 plus shipping for that unit.

I don't know what level of rebuild you need or want, but the rebuild kits are at the top of this page:

http://www.makcotransmissionparts.com/A904.html

When I went on my 904 rebuilding spree, I was able to rebuild three of them for under $200 by careful inspection and selection of parts.
Author:  Ed Mullen [ Mon Dec 28, 2015 12:29 pm ]
Post subject: 
I had dismissed that one since it said 89-92 3.9L.

I guess, depending on shipping costs, that may beat Napa.

I was going to get the most complete kit Rockauto has, and see how far it gets me. (autopsy will likely be complete before I buy anything for it, so I should have a handle on what I need prior to ordering).

FAIK I just need friction discs and seals. It leaks and is full of largely non-mettalic dust (and maybe a little water/rust), and the torque converter screws came loose all at once, but it was 'working' until the moment I pulled it.

The kickdown band was changed when I had it rebuilt like 14 years ago, and I haven't put much mileage on it since--no towing, nothing heavy, etc.

I can't speak to the condition of the rear band, so for the moment, am assuming I'll need to change it.

I did dump all the fluid out of it while driving, twice, that I can recall (rotten cooler lines and subsequent incompetent repair).

I think I'm going to need a better set of snap ring pliers than I have.

I may fabricate a clutch spring compressor, or buy one of the $50 internet ones. (I need to read a bunch of reviews, and check out people's DIY versions to make an informed decision).
Author:  Ed Mullen [ Thu Dec 31, 2015 2:08 pm ]
Post subject:  A904 year id
Junkyard finally found and gave me the 80's van compatable A904.

I changed the filter and adjusted the low/reverse band to 41 in/lbs--7 turns per specs for 1983 ("1983" stamped on tail housing--not sure that means anything.) per specs in FAQs.

It seems way loose.

Same post says 4 turns for 1984, up.

Before I install the pan, I'd like to be sure the band adjustment is correct.

What should I be looking for?
Page 1 of 2 All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/