73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: swilliams on August 02, 2014, 10:06:57 pm
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I have a stock 700r4 that has started leaking from what i assume is the front seal. It does not happen all the time just when ever it wants to but when it does it leaks about a half a quart or more. I have jacked up the truck looking for the leak (have not removed the fly wheel cover yet because i have to remove part of the exhaust to do so) there are no obvious signs of a leak. The only place I figure it can be coming from is the hole in the dust cover. Has anyone herd of this.
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when your moving wind can push fluid all around. so best thing to do is clean it all up and check for leaks. could be something simple like the o ring on the filler tube or a bad pan gasket and the vent tube can leak
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I have helped my stepson with the vent tube on his 2004 Taurus. His leaked out 2 and a half quarts. The under side of my trans has no fluid leaked on it. I recently had to replace the TV cable so i thought that would be it but nothing on or around it or the pan bolts i only have a few drops on my exhaust. This is the 3 time since the problem started that it has leaked about 2 months time. I cant be sure but the signs point to that it only leaks when it is sitting but like i said it does not happen all the time. Very strange to me. I have put cardboard down to try and see where it is leaking had it down for 2 weeks no leaks i cleaned and swept the garage and did not put it back down and what do you know it leaked and ran to one side so i tried to see anything but found nothing. I am going to have to pull the dust cove to check.
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Mine did the same thing after sitting for a couple of weeks. It was leaking out the weep hole in the yoke.
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Did u do anything for it
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A little rtv in the hole did the trick..
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with the yoke problem you will see oil sprayed up on the bed right above the yoke. rtv is a quick fix but i think inorder to fix it proper you have to remove the tail shaft housing
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http://www.73-87.com/7387garage/drivetrain/yokeleak.htm
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I have let my truck sit for 7 days. I was able to check on it the first 3 days with no leaks. The next 3 days did not check. Checked it today and found this....
(http://i36.photobucket.com/albums/e42/swilliams19733/A2183B68-79A2-4FA8-9516-5E5659FA1658_zps4nwupzuz.jpg) (http://s36.photobucket.com/user/swilliams19733/media/A2183B68-79A2-4FA8-9516-5E5659FA1658_zps4nwupzuz.jpg.html)
(http://i36.photobucket.com/albums/e42/swilliams19733/0A7CFCAC-0073-464D-A6A3-EAEAE390EA61_zpseme6gqiz.jpg) (http://s36.photobucket.com/user/swilliams19733/media/0A7CFCAC-0073-464D-A6A3-EAEAE390EA61_zpseme6gqiz.jpg.html)
(http://i36.photobucket.com/albums/e42/swilliams19733/115E3479-A200-4365-9CD0-014240D8AD6B_zps5pmlqlkz.jpg) (http://s36.photobucket.com/user/swilliams19733/media/115E3479-A200-4365-9CD0-014240D8AD6B_zps5pmlqlkz.jpg.html)
Someone suggested that it might be an overheating issue because before i installed my headers it did not happen but no leaks in first 3 days and...
(http://i36.photobucket.com/albums/e42/swilliams19733/5F65AE8E-3D88-457C-8D4E-ABBAC70CC37E_zpszwz7alph.jpg) (http://s36.photobucket.com/user/swilliams19733/media/5F65AE8E-3D88-457C-8D4E-ABBAC70CC37E_zpszwz7alph.jpg.html)
tranny fluid does not seem to be burned or discolored. Anyone have any ideas
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So it was just sitting for 3 days, not driven and leaked out all that?
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So, you have a static leak. Use a flashlight and mirror to locate the highest point that is wet with ATF - fluid runs downhill. Don't start it or drive it, just look for fluid traces around the fill pipe and TV cable seals, servo cover seal, governor cover, speedometer adapter, output shaft seal, front pump & seal, vent tube, shift shaft seal, etc. That is a lot of fluid for just a few days. Since the vehicle hasn't been moved, the only thing moving the fluid around is gravity.
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i recently had to change the TV cable. I cleaned around it real good and have not really found any fluid there. As you can see from the trail my garage floor drains back and to the left so for the fluid to get to the front of the tranny i would think it is a front seal. I just have not had the time to remove the exhaust crossover that covers the dust cover to be able to check it. I dont understand why it takes so long to start leaking.
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Can you unbolt the cover and shift it around enough w/o removing the crossover to use a small articulated mirror and penlight?
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i am going to have this weekend off so even if i have to remove the crossover i have to find out. if it is the front seal what will it take to replace it.
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If you determine the front seal is the source of the leak the trans will need to come out for repair, because you will need to remove the converter for access. Once the converter is out of the way, replacing the front pump seal is similar to replacing a timing cover seal or trans output shaft seal; a steel shaft and the stator support protrude up through the center of the seal. The pump seal is installed and retained with red Loctite and caged by a steel retainer ring. However, if the front seal is causing that much of a leak, you may have a pump bushing that is wiped or shifted forward, or a restricted drain hole behind the seal.
Obviously, the first thing to do is accurately identify the source of the leak.
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You will have to pull the transmission to replace the front seal. I also have an 700r4 in my truck, after blowing out 2 front seals, the 3rd time I found a builder, who put a homemade retaining plate over the front seal. Being from Toledo, Ohio area where these transmissions where made, the builder worked at Hydromatic, the plant that made these transmissions. He put's these plates on all his performance build's. Good Luck, Ken.
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Yeah being here in New Mexico we don't manufacture much of anything. I wonder if this is just a start of a long line of problems. Would not having the TV cable adjusted correctly have anything to do with it? Maybe i should just have the entire thing rebuilt.
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Refresh our memory - what year is the trans and roughly how many miles are on it?
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I pulled the paperwork on it . Time flies.... 6/01 700r4 reconditioned + TC . paid $517.33. 13+ years i guess i cant complain. The RPO code is a MXO 4-spd. auto. o/d trans. which i assume is a 700r4 but i dont know if this is the original or not.
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All the factory upgrades should have been completed by the last repair... although, some aftermarket upgrades were released as recently as ~2012. Determine where the leak is before deciding on a repair course, then if you are unable to correct it yourself, take it to someone reputable.
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I have not taken the truck an a trip longer than 40 miles in i dont know how long. Should i stay with the 700r4. I am also getting ready to up grade my heads and rear end.
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I would retain the 700R4 (aka: 4L60, MD8). A properly built 4L60 will manage 500 HP/500 lb-ft with no ill effects - more than that by the right builder. If you were planning on twisting it with a performance BBC, I would consider a different tranny. But, a mildly modified small block, no worries. There are plenty of references available to become familiar with that transmission. If you are shy about fixing it yourself, just find a reputable (preferably local) builder.
But, again, don't let the cart lead the horse. Find out what the leak is.
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Thanks for the advice.
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No signs of a leak running down.
(http://i36.photobucket.com/albums/e42/swilliams19733/1B32A4B8-A1B1-43CE-887D-B6F5448EFB85_zpsfd4ynyda.jpg) (http://s36.photobucket.com/user/swilliams19733/media/1B32A4B8-A1B1-43CE-887D-B6F5448EFB85_zpsfd4ynyda.jpg.html)
Nothing running down the front of trans where the front seal would be.
(http://i36.photobucket.com/albums/e42/swilliams19733/6BBABD5A-AC1A-493D-81E2-E5E125289292_zps94vzqt7b.jpg) (http://s36.photobucket.com/user/swilliams19733/media/6BBABD5A-AC1A-493D-81E2-E5E125289292_zps94vzqt7b.jpg.html)
A little closer but bad pic.
(http://i36.photobucket.com/albums/e42/swilliams19733/10EE5C71-E43F-42F8-B35D-77E7B060727F_zpsivjuzmv6.jpg) (http://s36.photobucket.com/user/swilliams19733/media/10EE5C71-E43F-42F8-B35D-77E7B060727F_zpsivjuzmv6.jpg.html)
(http://i36.photobucket.com/albums/e42/swilliams19733/9D48D307-1D8C-46F0-A2BE-06FDDCC7E32E_zps9c7k84bw.jpg) (http://s36.photobucket.com/user/swilliams19733/media/9D48D307-1D8C-46F0-A2BE-06FDDCC7E32E_zps9c7k84bw.jpg.html)
No connection leaks
(http://i36.photobucket.com/albums/e42/swilliams19733/F895A10A-9492-44D1-967A-8C71AB3F2A89_zps6tze9byl.jpg) (http://s36.photobucket.com/user/swilliams19733/media/F895A10A-9492-44D1-967A-8C71AB3F2A89_zps6tze9byl.jpg.html)
(http://i36.photobucket.com/albums/e42/swilliams19733/7DF24EE4-F785-4441-81BE-A432267E352B_zpstvqelqtx.jpg) (http://s36.photobucket.com/user/swilliams19733/media/7DF24EE4-F785-4441-81BE-A432267E352B_zpstvqelqtx.jpg.html)(http://i36.photobucket.com/albums/e42/swilliams19733/CF919E2D-F383-40DF-89C0-093E20F904AA_zpsaamcdmwp.jpg) (http://s36.photobucket.com/user/swilliams19733/media/CF919E2D-F383-40DF-89C0-093E20F904AA_zpsaamcdmwp.jpg.html)
Paper label on torque converter no trans fluid on it (http://i36.photobucket.com/albums/e42/swilliams19733/4DDC200E-E913-486B-A8FA-E2BDED45631D_zpsgrgd1npa.jpg) (http://s36.photobucket.com/user/swilliams19733/media/4DDC200E-E913-486B-A8FA-E2BDED45631D_zpsgrgd1npa.jpg.html)
The only clue i got is the fluid in the dust cover.
(http://i36.photobucket.com/albums/e42/swilliams19733/6FEDE603-E841-4FF1-B6D5-257308AEF506_zpsuq7szxup.jpg) (http://s36.photobucket.com/user/swilliams19733/media/6FEDE603-E841-4FF1-B6D5-257308AEF506_zpsuq7szxup.jpg.html)
Is it still possible that the front seal is out?
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Relying on unclear pics - a WAG is pan gasket or front pump o-ring. Although, that is a lot of fluid for either of those, under the circumstances.
Leave the dust cover off and add dye to the trans fluid then use a UV lamp, checking it periodically while it sits stationary over 3-4 days....
If the pan is leaking, install a sand cast aluminum pan such as a Hughes Performance HP3780 (http://www.summitracing.com/parts/hup-hp3780). The pan will never leak again AND it will strengthen the case.
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What type of dye do i use
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Tracerline oil based dye (http://www.summitracing.com/parts/trl-tp-3400-0601)
Tracerline Optimax LED Light (http://www.summitracing.com/parts/trl-tp-8690)
The yellow filter glasses greatly enhance the effectiveness of the UV dye system. Shopping around, you may be able to rent or find a similar product for lower cost. I use Tracerline for difficult leak diagnoses with excellent results. Fortunately, I don't need to use it very often.
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Thanks again for the help