So tonight i was racing a guy who obviously had a lot of nitrous (we'd stay dead even then all of a sudden he'd take off with black smoke pouring out his exhaust), and all-of-a-sudden i started making some smoke of my own, but in a bad way. Looks like my front pump seal blew AGAIN, it's pouring out between the bellhousing and the tranny. So my question is, what did i do wrong? I'm thinking that maybe i got my clearances too tight and when i really whomped on it stuff got warm enough or moving fast enough to push the front pump far enough off to start gushing. Sound about right? The first time this happened, i decided to take it to a local transmission shop and have it professionally re-assembled. So, to the tune of $185, i got it professionally re-assembled, which included not even checking the end play to see if i had used the right thickness of #1 and #2 thrust washers. But, everything worked, ....until now! Anything else anyone can think of that could cause this?? Assuming that the gasket surface was completely cleaned? Sorry to rant and rave, but i'm currently VERY angry--pulling transmissions is not very much fun.
transmission again Can you tell if its coming from the front seal or the pump mounting gasket to case. Have seen some with cracked bolt holes, pump housings and even torque converter hubs that were cracked where they are welded. If it is the seal, then the converter hub is either scored badly or is not running true center with the flywheel and crank. Those hubs can be replaced and maybe if yours was a rebuilt converter it was welded on crooked. Dial indicator with it in a lathe will tell. Engine vibration is another angle, loose bolts, bad main bearings etc. Cracked bellhousing is another. Was the pump disassembled and the two gears checked for cracks and wear? I don't think it was your clearance adjustments inside, something is misaligned or a crack is opening up with heat and fluid pressure. Have someone put a test gage on the trans and see if it is within specs in all gears. Had a reverse manual valve body that I had ordered cause similiar problems, it had 300psi in nuetral which was way too much, sent it back and got another one and was just fine. Just a few thoughts of mine.
Thanks again, old guy! Thanks for the response old guy. I should start paying you by the hour! The leak is definitely coming from the pump to case gasket. It runs all over the transmission, down the bellhousing, and literally POURS straight down. Nothing coming from inside the bellhousing (as would be the case with the seal on the converter). I'll have to check for cracks when i disassemble this time, but as of last time there were no obvious cracks. See, i've had this transmission in for quite a while, but was getting a nasty vibration. So, i took it out, found out that the case was hitting on the crossmember and also that the internals were vibrating (worn thrust washers), probably due to a bad torque converter as well. That was the last time i posted, and you told me that the #1 and #2 thrust washers should be the same size (within .003)...which is not the way i had it originally. Originally i had put it in with the numbers on the thrust washers matching... i.e. using thrust washer #1 with (1) stamped on it and thrust washer #2 with (1) stamped on it, even though they were different thicknesses. So was i correct to use the same thickness #1 and #2, right? My manual simply says "check endplay and adjust using different thicknesses of #1 and #2 thrust washers". Not very helpful... Anyways, so i put it all back together, checked the endplay and found it to be .013 (but was the pump tightened ALL THE WAY DOWN when i checked it? I only put two bolts in to check it. worried....), bolted it back together, and threw it back in there. I had also added a new torque converter (new to me, i bought it used but supposedly with low miles, a TCI 2400 stall), put new front pump gears in *correctly*, and put a new band in it. I made it about half way around the block and it started pouring...literally...out of the pump to case gasket. Pulled it back out and decided that i really didn't want to pull it out and put it back in anytime soon, so i took it to a shop. He just basically pulled everything out, inspected it, put it back together, impacted the hell out of it, and wrote me a big bill. But, it worked...until now. Something that started happening after he fixed it (but not when i first put it together) was when i was in first and i stepped on it any more than usual acceleration i would get a rather loud....noise...hard to explain...sounded like a bike when you're changing sprockets and not quite to the next sprocket...a grinding noise that was very short and very loud. Hopefully i'll be able to see what it is when i get it out and disassembled. I'm positive i fully seated the converter though. Otherwise...bellhousing isn't cracked....since i didn't have this problem before and my engine is new (less than 10k w/ profession rebuild and assembly), i think i'm going to rule out engine problems for now.... Well, i've got some work to do....thanks for all your time old guy! ~Chris
By the way....transmission is '78 C4, Valve body has been modified with TCI kit, PEE V12 on the tag, nothing else special.... Oh, my other question was whether not having a kickdown would hurt anything?
When you put the converter in are you sure you got it seated the whole way onto the pump ,it dosnt take much and if you proceed to bolt to the bell housing to the engine it could put way to much stress on the front pump. if that were to happen all is not lost just hope you dont jog the engine around to get to the converter bolts with the starter.hand crank it if its tight locked up then converter isnt seated .and not having a kickdown shouldnt hurt anything.Good luck.
Trans Stuff Been giving some more thought to this and I think that there may be a torn pump gasket or foreign material on the case or pump itself. Maybe a stripped bolt hole in the case too. Early models had a large rubber seal around the pump itself and shamefully, I left it out one time and the red stuff came a gushing out. They were the 60's C4's so your ok unless someone has put the early pump in yours. The kickdown does nothing but put the trans into 2nd gear when the lever is activated, no problem with it disconnected. Forgot to tell you that I agree with you 100%, taking the dang thing in and out is not a good way to spend quality time with the Mav, running down those Chevy's and such is!!
So i got it apart and and i'm about 99% done putting it back together. Now of course i don't have the world's most accurate tools but it looked like my torque converter was okay (laid a piece of steel across the "neck" of it and mic'ed the distance to four parts of the converter and they all matched, plus it's relatively new). Haven't checked the pump to see if it's warped or anything, but looks good. No material on the mounting surfaces.. The gasket was torn, but the way in which it was torn leads me to believe (along with the amount of fluid that was coming out) that the front pump had actually popped off of the case rather than just blowing out the gasket. All of the thread holes were okay except for the very top one, which i am just going to put a longer bolt in and put a nut on the back. Will get the front pump in tomorrow and find out the endplay and all that. Just thought i'd let you know!
Finally got the tranny back assembled and in the car. Just have to put the exhaust and driveshaft back in. I think i found out what my problem was...with a .020 thinner thrust washer, i was getting endplay of .024. So, doign the math, i guess my clearance must have been .004 last time...minimum is .008. I guess i just didn't tighten the pump down enough last time when i checked it. Put some new bands and clutches in there while i was at it this time too. Thanks for the help!
built a c4 for a buddy had the same trouble worked fine until he ran it at the track(street car 10.19 ON NOS) his AT cooler was to small it was running to hot had trouble with drum seal are the front seal went to a large AT cooler has been working fine do you have a good cooler on yours??
