91 700r4 repeat front pump leak

[463]

my pump is leaking again after 21000 miles on a rebuilt pump and seal, and a bout of -30f temps. the time before was 12000 miles prior on a rebuilt trans that had washers placed on the torque converter bolts by the teck at the dealership, why? because that the way the last repair was made before he worked on it , and thinking it needed them he replaced them. 12000 miles prior to that the pump seal leaked and it was rebuilt (pump)and had washers placed on the torque converter bolts to move the converter back to get a better seal on a better part of the converter shaft to stop the leak. again winter time temps with all the pump leaks. #1 is the pump not alined correctly when it's install ? #2 is the converter out of ballance? #3 is the end play in the rebuilt 305cid eng crank shaft to much end play causing the pump to fail. the end play is specked at .001" to .007" in the book for a 305 cid. this has yet to be checked. # 4 a internal psi build up in the pump area and in turn forces a trans leak when its cold -20 f and lower. something is not right with this unit. as i'am running low on ideas . with my 1986 305 with the 700r4 trans has 211000 miles with no leaks.

[silicon212]

I would say that #4 is the most likely culprit and the cause of this is usually a plugged or restricted oil drainback hole in the pump.

[463]

Originally Posted by silicon212

I would say that #4 is the most likely culprit and the cause of this is usually a plugged or restricted oil drainback hole in the pump.

that may be it. the pump with the added psi from the washer mod twice and a teck may have over looked a restricted oil drainback hole last time. the common thing is the cold temps. thanks again silicon.

[Blue Bowtie]

The pump bushing may also have some wear (even at 21K) that allows excessive movement of the converter. A stock pressure control valve (unmodified) may also impart extra pressure without allowing adequate bleed off of excess oil.

[463]

i wondering as the temp in the trans warms if the warmer oil would flow easer and not come out at that front seal. the two times the leak happened with out the washer shims in it's been a -30 to -40 f and just run a short distance. three weeks ago when it was in for a oil change we noted a small drops on the fly wheel cover so off it came and was cleaned out. there was a very very small trace of oil sling on the conveter but not enough to cause a alarm. this was placed on the watch list. apx 1000 miles and two weeks later it was started up cold and ran into the shop when we noticed red trans fluid in the snow where the car was parked. in the shop it dripped 3 to 6 oz on the floor. i should go start it and see how much or how bad it is as it's -10f today.

[463]

just went and checked it. there was some drips in the snow. no forward or reverse in the first 20-30 seconds then ok (that tells me to cold and lower fluid level).after a 300 foot 5 mph run i went and walk the area to find a trans oil trail of one red spot every 30 feet or so. it's looking like a trip to the gm shop. thats a $500 to $2000 dollar trip.

[463]

update: after booking it in at the gm shop for a monday 9am app. i went and had a talk with a old trany man that been a long time friend of mine. after hashing it out he is thinking it might have a crack in the flex plate ?? so we will closely entertain idea real close, like pull it and magnaflux it. this repeat offender must be fixed.

[j cAT]

miles plus pump equals replace torque converter...

[463]

well i had to hall two mechanics and the service adviser under the car and show them this problem note the cracks around the converter bolts(white arrows)

[463]

so the flywheel was replaced front bushing front seal in the pump and the converter. here is a pick of the bushing. so time will tell if we got i right this time. the car is running a 100% now. just the labor the hash out at the gm dealer.

[silicon212]

Wow. So, they did replace the converter? That's good, otherwise you will be here again.

[j cAT]

[quote=463]so the flywheel was replaced front bushing front seal in the pump and the converter. here is a pick of the bushing. so time will tell if we got i right this time. the car is running a 100% now. just the labor the hash out at the gm dealer.

there is a TSB about this, that I found when you posted this...that is why I stated bad pump seal high miles means torque converter needs replacement..the use of washers is a no no....they tried to bypass a known issue....

a contaminated torque converter can cause higher pressures causing the seal to blow..

[463]

update: heres what they did,rear trans mount gm $109 + flywheel gm $219+ converter rebuilt unit $187 + frieght charge $20 + like the "+" signs and seal asm $11 + bushing $13.85 +seal $6.75 + gasket $11.10 + trans filter kit $52.75 + dextron V1 $67.50 + 6.72 hrs labor = $605 + supplies $17 + 10% tax $132.28 for a wait for it a grand total -----------------------------------------$1455.05 cdn funds just say it quick it, and sign here______ i did spend 45 min in the big dog's office for a explantion. the last time two years back when they fixed it there was no flywheel, t/c ,filter or fluid, rear trans mount and the cost was $449.23 labor inc. the labor rate is $10 a hr lower than now, for a explantion the difference of $460 +- and he said the labor was $10 an hr higher today and 2.8 hrs more for the work performed and the last time there was a time short shortage as i saw the hard copy where a mechanic failed to clock out on the work order so there error was in my favor that time.