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Eagle A904 transmission problem |
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gui67
AMC Apprentice Joined: Nov/11/2013 Location: France Status: Offline Points: 45 |
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Posted: May/15/2018 at 8:30am |
Hello, I have rebuilt the A904 of my fathers eagle.Previously, it was slipping very bad. So I ordered a complete kit with all clutches and steels. During the rebuild, I saw that one clutch pack was completely burnt. Now it does not slip anymore, but it does not start in first gear anymore: with the lever in D, 2 or 1, it will always start in second gear. The line pressure is around 50PSI at idle and 80PSI with the lever pushed to the rear. but I don't have any pressure on the rear servo with the lever in 1 position. I have pressure here in R however: around 150PSI I wanted to check the governor pressure while driving, but the governor pressure port is nearly impossible to reach (it is on the transfer case adapter right?) to get a reading without taking the crossmember out... Do you know what could be the cause or where I should look for the next diagnosis steps? Best regards Guillaume
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1970390amx
AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3312 |
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I would say you need to get a governor pressure reading. Sounds like its sticking and not doing what its supposed to do. You could have valve body problems but with out knowing what the governor is doing it will be hard to tell.
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1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box |
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DaemonForce
AMC Addicted Joined: Jul/05/2012 Location: Olympia, WA Status: Offline Points: 1070 |
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I would reexamine the valve body first.
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1971 Javelin SST
American 304 2v | FMX | AM20-3.31 1983 American Limited Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72 |
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gui67
AMC Apprentice Joined: Nov/11/2013 Location: France Status: Offline Points: 45 |
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Hello,
I have just measured the governor pressure We have 15 psi at 18mph then 20 at 40mph and 30psi at 60mph. So it is louer than expected. I suspect a problem in the valve body. Do you know where it is possible to find an hydraulic diagram of the valve body? Thanks Guillaume |
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gui67
AMC Apprentice Joined: Nov/11/2013 Location: France Status: Offline Points: 45 |
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Hello, We have removed the valve body, checked the valves and the governor too: no change. Now we have taken the whole transmission out of the car again and disassembled everything: everything looks good. I have tested the 2 bands and the clutch: the piston move with air pressure, everything is OK. However, there is something stange for the play or the output shaft: when I put the clip on the shaft, there is no play between the planetary and the clip. But the whole shaft, governor and planetaries... moves compared to the case. I have made a video: Could you please tell me if this is OK. I don't think I have forgotten any thrust washer or anything. When I put the extension housing, the housing pushes the bearing to the front, which pushed the whole shaft, planetaries... to the front too and the play is reduced. But I wonder if the play is normal without the extension housing. Thanks in advance Guillaume
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carnuck
AMC Addicted Joined: Mar/31/2010 Location: Seattle Status: Offline Points: 3942 |
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Maybe the shift selector isn’t moving all the way to first? Did you replace the torque converter? Was it a lockup? (Early ‘80s Jeeps and Eagles mostly were) Burnt planetary clutches usually means poor or slow engagement from the piston behind the clutches (due to clogged trans cooler in the rad or a broken oring on the input shaft)
If pressure drops and metal is found in the pan, then a cracked pump casing (converter not fully engaged when tightened up or a TH400 sleeve in crank pilot hole forcing converter too deep if there was a Jeep Rebuilt motor swap (like pre’80 TH400 pilot sleeved crank in later block with your Mopar designed AMC case trans) |
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http://forums.amceaglesden.com |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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You may want to re-read his post - >>Now it does not slip anymore, but it does not start in first gear anymore: with the lever in D, 2 or 1, it will always start in second gear.< In other words, he's NOT starting out in 1 position - it simply appears to have no low gear and starts in 2nd no matter what, D, 2 or 1 so it's not a matter of the shifter not moving the transmission lever to the 1 position.
Apparently, it starts in 2nd even in DRIVE. It would help to know the YEAR of the car and the engine - but with a 904 it almost has to be a 4 Why do I say that? Because they used the 998 behind the 258 in every case. The 904 behind the 4 was a baby 904 - really tiny. 4s don't have lockup, 6s do have lockup - Lockup converter was dropped with 86 according to the real Eagle people. |
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carnuck
AMC Addicted Joined: Mar/31/2010 Location: Seattle Status: Offline Points: 3942 |
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Well Bill, since it’s an Eagle, it has to be minimum 1980, and the 6 cyls got 998, which is lockup capable and they did run lockups with the 4 or 6 cyl, but they really weren’t ready for prime time. The 999E (aka 32RE) used much later than Eagles (‘93 up) with Electronic controlled lockup were better. They improved the front pump and converter design (round tube shaped billet neck brazed into the torque converter instead of the notched tube style drive on earlier ones that cracked and dumped mega amounts of Dex ATF, usually after a new rpm related vibration shows up in 904 or 998.
TJs and YJs with 4.0 and 2.5 ran the better trans, if you can find one, all the way to ‘99. The 4 cyl had enough length for AW4 but the 4.0 needed more room or zero lift due to short driveshaft. (Yes, I know we’re talking Eagles) I thought maybe the gear selector stuck internally or the fried clutches are trying to move it alone. (I even had the 727 in my J10 do that due to lack of maintenance and excessively torqued loads without a cooler.) If someone messed with it before and didn’t leave space for band engage/disengage then the clutches will fight it. If the If the first gear piston seal is weak, the clutches burn up from slippage. If the shifter lands between first and second and the 2nd band is too tight, the clutches can fry. (AMHIK). If the valvebody has an extra checkball, things operate wrong. It’s not: unmatched axle ratios, which would take longer and the viscous coupler is taken out long before affecting the trans. Not dragging brakes. Previous owner messing with the valvebody. (1 Check ball in wrong place. Happened long ago when someone added one and I didn’t notice. Baby 904 is small bell on 2.5 60 degree and SBC 2.5L pattern Iron Duke Eagles (which went away in’83) People mistake 904 and 998 with 999 if they aren’t in the “know”. Baby 904s, used in Mitsubishi and RWD Dodge Colts and pickups with small motors. Edited by carnuck - Jul/24/2018 at 11:29pm |
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1970390amx
AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3312 |
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i am just going to call this thing a torque flite. They all operate about the same. You did not say but I hope the gov pressure reading was zero at a stop. In order for the transmission to start out in low gear only the rear clutch pack need apply, and the low roller clutch work properly. To shift to second the intermediate band needs to apply. If it starts in second the band is applied. Is the adjustment correct? Did you take a pressure reading of the intermediate servo stopped in drive? Should be zero. Does the transmission upshift 2nd to 3rd? If you have zero gov pressure at a stop and have pressure in the intermediate servo at a stop you need to look to the valve body for a problem. May need to replace it.
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1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Keep in mind Eagles are what I do - I've owned five and worked on more. What I said can be verified if ya don't trust a professional trained and experienced and having done it for a living for a few years. First, NO, AMC did NOT use lockup converters in the 4 cylinder Eagle. PERIOD. For lurkers and others here - you can verify what I say in multiple ways - first is the AMC TSM, next is the Eaglepedia, then there's allpar, and other resources. AMC used three converters in Eagle - Conventional non-lockup with the FOUR cylinder engine Lockup high stall Lockup low stall, these last two with the 258 The little 904 isn't just another Mopar in that it's a lot smaller and uses a smaller and different pan gasket. Again, how do I know this? Maintaining a 1982 Eagle SX4 with the iron duke and making two trips into town for the correct gasket because my stash of 727 and 998 parts and gaskets didn't work.
I call it a baby 904 because the store did when they found a footnote in their books and shrugging and going back and looking again instead of saying "oh, then this will work" like they did at first. Anything I've said can be verified and looked up if you don't trust over 4 decades of transmission and other auto work. So please don't give me that - >>Well Bill, since it’s an Eagle, it has to be minimum 1980, and the 6 cyls got 998, which is lockup capable and they did run lockups with the 4 or 6 cyl,<< Good grief, you think I have no eagle experience or haven't rebuilt transmissions professionally or been factory trained (because I have) Frankly, I take offense at the comment as written - I'm not a beginner and you don't have to explain Eagles to me - I know 'em inside and out. I really like 1970390AMX's approach a whole lot better- professional, asking all the right questions, etc. We don't have all of the information, either - it's a rebuilt transmission - is it an original Eagle transmission properly rebuilt with NO lockup converter since AMC did NOT use them in Eagle cars?? Or is it a core someone changed out the tail shaft and other goodies to try to make an Eagle transmission? Year? Since they say 904- then I know it's a 4 cyl, but then are they correct in it being a 904 - and the correct 904 for Eagle? Trust me, they ARE different. Yes, it's a mopar transmission and yes the clutch and band operation are the same - but if they tried to use wrong parts in it, if they went to the parts store and bought a kit for it - it may not be right because those little ones used behind the Pontiac engine are different in AMC. I'm done with this topic, you can mess with it, or with luck, 1970390amx will stick with it and get it resolved correctly, without a lot of guessing. I don't need to be talked down to or smacked around as if I have no Eagle experience and no automatic experience. By the way, I DO have books loaded with all of the hydraulic system info, troubleshooting and more - from college and from AMC if 1970390 doesn't, but I bet he does as well. Edited by billd - Jul/25/2018 at 9:38am |
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