Finally fixed a defect the big three auto manufactures have neglected to do.

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I have never understood why the big three auto makers have never put a drain plug in their transmission pans. Well I finally did this on my wifes GMC jimmy. Transmission is a 4L60E.What I did was buy one of the drain plugs that you drill a hole and screw it together in the pan but the problem with that is there is going to be about a 1/4in of fluid that will not be able to drian because of the backup nut thickness so I sawed off the threaded part of the drain plug and welding it flush to the pan so now all the fluid that is in the pan will be able to drain.Main reason I wanted to do this is because I do all my own maintenance and I would neglect the transmission service because it is a mess and a pain but now I will be able to keep fresh fluid in the trans more aften than I would. Attached ImagesLast edited by 737mechanic; 08-04-2008 at 09:15 PM.
Reply:Rest of pics Attached Images
Reply:Looks good!I never really understood why transmissions have no drain plug.
Reply:The reason I was given years ago is because with a plug then the fluid gets changed but not the filter. If you have to drop the pan just to drain it then you may as well change the filter also. BTW my 2000 GMC 1500 was a tranny drain plug. I am not sure which automatic it is though.Tim Beeker.
Reply:My dad has been installing drain plugs in automatic transmissions for years. Braze a half collar on the pan and stick a pipe plug in it.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Tim is correct.  The manufacturers WANT the pan dropped so you change the filter.Also, if you only change the fluid in the actual pan, you are only replacing a small percentage of all the fluid in the system.  You are not taking into account the fluid in the Torque Convertor, the Cooler and all lines to and from, and also the fluid in the transmission itself.A better way to keep your transmission in top condition is to replace your filter, then take it to a shop that you trust where they will hook up the appropriate equipment in-series to replace ALL the fluid in the system.  It can be done simply by hooking into the transmission cooler lines, and or a pressure line.  Depends on make and manufacturer.Just changing the oil in the pan leaves many litres (or quarts) of used and potentially burnt fluid in the system.Later,Jason
Reply:Originally Posted by tnjindThe reason I was given years ago is because with a plug then the fluid gets changed but not the filter. If you have to drop the pan just to drain it then you may as well change the filter also. BTW my 2000 GMC 1500 was a tranny drain plug. I am not sure which automatic it is though.
Reply:What everyone said about filter is true, but its alot nicer to drain pan before dropping it.     I bought two of those plugs7 or 8 yrs. ago.       Each time I make an excuse why I don't have time to install them.
Reply:Originally Posted by Black WolfTim is correct.  The manufacturers WANT the pan dropped so you change the filter.Also, if you only change the fluid in the actual pan, you are only replacing a small percentage of all the fluid in the system.  You are not taking into account the fluid in the Torque Convertor, the Cooler and all lines to and from, and also the fluid in the transmission itself.A better way to keep your transmission in top condition is to replace your filter, then take it to a shop that you trust where they will hook up the appropriate equipment in-series to replace ALL the fluid in the system.  It can be done simply by hooking into the transmission cooler lines, and or a pressure line.  Depends on make and manufacturer.Just changing the oil in the pan leaves many litres (or quarts) of used and potentially burnt fluid in the system.
Reply:I was impressed with saturn's spin on tranny filter.DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:That's a nice modification there 737mechanic. Yeah littlefuzz my 98 Saturn SC2 has the spin on transmission filter. It looks just like an oil filter.Lincoln AC/DC 225/125 Stick Linde HDA-300 MillerMatic DVI MIG Miller Dynasty 200DX Hypertherm Powermax 1000
Reply:Originally Posted by littlefuzzI was impressed with saturn's spin on tranny filter.
Reply:There was a time they had drain plugs. The torque convertor had a drain plug as well. Then they started making disposible cars in the 70's.
Reply:Darned nice photos, too!
Reply:Good job OP..to all who say that the filter needs to be changed its true..But, many DIY dont wnt to undertake the dirty/messy task of a pan drop and ignore changing it until something goes wrong (WHICH IS TOO LATE).So with the Op doing regular changes every 7-15K., He will have a better tranny than the people who says the filter needs to be changed and pan dropped., becuase most of them are not changning the filter or fluid becuase of mess or the costs..I beleive most are not going to pay a shop every 7-15k $100 for a drain of the tranny or do it themselves.Though they are one or two who would.The option is there for the OP to change the fluid or filter, and the filter more likely to get changed with the fluid all drained out before unbolting.Besides this is a good idea, becuase it makes changing the filter a whole lot less messier..Good work again OP!Last edited by goodoleboy; 08-05-2008 at 08:08 AM.
Reply:Yes,  but then came the power flushers.  (Power Flushers to the rescue)
Reply:Originally Posted by tresiThere was a time they had drain plugs. The torque convertor had a drain plug as well. Then they started making disposible cars in the 70's.
Reply:Nice job. Done a few myself. The only thing to remember is that some manufactures void the tranny warrenty if you do this. I know of a couple guys that had this trouble when I work as a mechanic a few years back. Wasn't a good seen.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Originally Posted by 737mechanicProblem with your theory is that unless you have a bad transmission the filter is most always in perfect condition and does NOT need to be replaced as often as the fluid needs to be changed.Next time you drop your pan take a good look at the filter and see how clean it still is.BTW whether you drop the pan or not you will never get the fluid out of the converter.
Reply:I'm a stickler for maintenance and have always done my own servicing. It's much cheaper than having someone do it and I know it's done and not just charged for. Yeah, I have seen this done more than once but once is all it has ever happened to me. I have read more than once that you should braze transmission pans because they are brittle and will crack when welded. I guess they can. I've welded up several that had holes knocked in them from running over some of our caliche rocks and welded several drain plugs in too. I have had exactly one crack. Really bothered me wasting that new ATF when I pulled it off to fix it but I wasn't about to try to save it.
Reply:A little off topic; but thought you guys would love this...Where I work the started is under part of the manifold! Awesome.
Reply:I have and after market pan on my 7.3 Diesel, torque converter has the drain plug and I usually open the line above the tranny cooler and blow out with compressed air.Don't know if this is OK but has worked for me. About that business of drilling the torque converter to place a plug, is there anywhere that more info could be found. That seems like a must have on the converters if you are going to do your own services. Thanks ."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Originally Posted by Black WolfI will respectfully disagree with your comments based on the following:My post had nothing to do with a "Theory".....  I am a Journeyman Automotive Mechanic, and I am factory trained by Ford Motor Company as I worked at a dealership in the early 90's.Agreed - the filter does stay clean as long as your friction disks do not wear.Agreed - the filter really does nothing to help with burnt fluid.Disagree - Dropping the pan or not has NOTHING to do with getting ALL of the fluid out of the  transmission.  You can only replace ALL the fluid (with tranny still in vehicle) using two methods:1) Drop Pan and Drain Torque Convertor - still leaves a small percentage of "old" fluid in the valve body and passages, cooler and lines.- For the ones that did not come factory with a drain - It was common practice to drill a hole in the torque convertor to drain it, then thread in a pipe tap, and install a pipe plug.  We did LOTS and it was a FORD approved modification.2) Hook up in series with a Tranny flushing machine.  Looks kinda like a two chambered Varsol tank with a bunch of hoses etc.  One reservoir you filled with new fluid, the other reservoir was filled with the old fluid as the vehicle was ran.  FORD approved - heck, it was a FORD service tool made by "Rotunda"- Because you are hooked "In Series"... ALL of the transmission fluid can be exchanged with new product (never mathmatically 100%) and is the best method of servicing the transmission.  When to change the filter is up to the manufacturer, and varies by make and model.When flushing the tranny, it is also a good idea to have an experienced technician checkover the tranny - Take a reading on line pressures etc, and to tighten bands where possible.Mechanic getting up and leaving, Welder sitting back down....Back to the point of the original post.  Nicely installed plug.  Good thoughts to make it flush and weld it on.  Welds look nice.  It should do a good job for years to come.....And it will make it much cleaner and easier to drain the fluid from the transmission oil pan for WHATEVER reason you may have.
Reply:Well there you go.... sounds like we are coming from more or less the same background.As you said - "All good points" Later,Jason
Reply:737mechanic, I was thinking about your dilemma...When I saw this hydraulic pump reservoir, that needs to be drained... but there's no drain plug. Attachment 22607I replaced the torn boot over the pump handle, (it probably let rain water in) and Teflon taped the leaking pipe plug.Since there's no drain, what we'll do is put a wand made of 1/4" tube in the fill hole, and pump the fluid out. We pull fluids out of  lots of stuff that way.About drilling torque converters - I always wondered if the metal chips trapped in the precisin built converter from drill break-through, could cause more damage than  dirty fluid ever could.Good LuckLast edited by denrep; 10-19-2010 at 11:32 PM.There is a method of draining all of the fluid in a transmission. Its fairly redneck, but it works.Requirements: two 5 gallon buckets and an ***-load of transmission fluid.Fill one bucket with the fluid, and put a small amount in the other (there is a reason for this). Disconnect both lines running to the transmission cooler and submerge one in the bucket full of fluid (all the way) and put the other line in the bucket with a few inches of fluid. Unless you know the in and out directions of the lines, you don't want one drawing air.Start the engine and with foot on the brake and someone watching the bucket, throw that bad boy in drive.Its what I've done and it works at clearing out everything.
Reply:Originally Posted by EnderThere is a method of draining all of the fluid in a transmission...Disconnect both lines running to the transmission cooler and submerge one in the bucket full of fluid (all the way) and put the other line in the bucket with a few inches of fluid....
Reply:Most sound like good ideas on changing tranny fluids ..my experience is with the old 60 -70s mopars and fords. I was told never replace the fluids IF you let the tranny go over 30,000 miles. You stand the risk of losing the transmission due to the abesto fibers floating around in the fluid IF the internal clutches are worn beyond a certain point. These fibers acted like sandpaper and kept the internal clutches engaged. And if you changed this fluid, then you removed the fibers and the clutches lost the tolerences needed to engage properly.Well, thats my experience with transmissions. Todays cars are a whole different breed altogether.
Reply:Denrep:Mopar 727/904, and thereby extension 500/518, automatic transmissions activate the front pump when the transmission is in drive (hence the necessity of having the trans in Drive during the exercise). I know there are some ford and chevy transmissions that also do the same thing.Unomike: What you've heard is kind of a 50/50 thing. A lot of old greasers still hold true to that sentiment. In addition, those "reverse flushes" where you bring it into a shop and they reverse flush it are notorious for blowing up transmissions. They have a habit of moving around sediment deposits that are basically keeping old trannies alive. That is why there is a clause in almost every shop that does it that if you have a transmission that is basically on its way out, they are not at fault when they blow it up.
Reply:Originally Posted by EnderDenrep:Mopar 727/904, and thereby extension 500/518, automatic transmissions activate the front pump when the transmission is in drive (hence the necessity of having the trans in Drive during the exercise). I know there are some ford and chevy transmissions that also do the same thing.