tranny ghouls when i DONT need them. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cliffsta · 12-21-2004, 12:01 PM

Well, my transmission might be takin a turn for the worse. It's started leakin ATF very bad, everywhere i park for more than 10 hours there is a nice sized puddle of it, and at my normal spot here at home, it looks like the wrekc of the Exxon Valdez. I haven't checked it in a week or two, cause i never really noticed it was all comin at once (i always park in one spot so there is a big puddle, but i just noticed the "new" spots)
It's also getting real bad about not going into drive. Like backing up down the driveway and putting it into drive, it wont go, or it will start to roll forward barely, giving it the gas has no effect, and finally it LUMPS over into drive. Used to only do it once when first going, now it does it consistantly until the truck reaches operating temp.
I gotta go get gas and when i get back ima check the ATF level, but are there any thoughts on how to stop the leak? My dad said he thinks its comin out the back, as he and my uncle changed the rear mains (if that applies or not, don't get us lying) and it doesn't leak oil. Also, is it just the modulator sticking that won't let it go into drive when it's cold?
And long-term, how much generally does a tranny rebuild cost, or at least some solid maintenace?
I know thats a bunch of vague ?s and its kinda long, but i'd rather learn now then, well, when i'm staring at a busted TH350C at a tranny shop...
Thanks guys and gals,
Cliff

leastbay · 12-21-2004, 01:41 PM

i have sort of the same question i am in the process of rebuilding my engine . My tranny leaks but i dont know where from but other than that it seems to work just fine its a th 350 would i just be better off getting a rebuilt one? or how hard is it just to change the seals..

dswancutt · 12-21-2004, 02:26 PM

Cliff;

Try to wipe it clean as best you can to see where the leak is. It could be the front seal, tranny pan gasket, shifter input seal, tranny lines, rear seal etc. A little tranny fluid can make a huge mess under the truck. Low fluid will make it not want to shift. My 78 does the same, but can be real intermittent, some days it leaks, some days it doesn't, and it now whats to slip the first time I drive it. If you change the tranny pan gasket, I would suggest looking on eBay for a chrome pan with a drain. With a little bit of looking, you can find one for under $30.00 shipped to your door. Hopefully it is something minor. DO NOT USE ANY OF THE STOP LEAK STUFF. It's great if you going to sell you vehicle, but it will bite you on the butt latter on. I did this and it leaks worse now that it did before. I was quoted $550 - 600 dollars to rebuild a turbo 350 if I pulled it.

Doug

Jonboy · 12-21-2004, 02:32 PM

The not going into gear problem is probably related to being low on fluid. If it is leaking that much, it will shift funny.

Make sure the trans cooler lines are tight on the side of the trans. Also, check the seal on the dipstick tube to make sure it is not leaking from there. GM has an updated tube with a boot type seal and a locking dipstick tube to prevent leaks. There was a recall about transmissions building up heat and pushing fluid out of the dipstick tube. It would then land on the converter and burn the truck to the ground.

you might check to see if the seal inside teh tailshaft is leaking. There is a weephole in the driveshaft of some trucks that will leak if the seal is going bad. I believe there is an article on www.73-87.com .

Other than that, the only other places that I could think of that may be leaking are the front and rear trans seals.

Slonaker · 12-21-2004, 05:15 PM

I have a TH-350C that had a lot of leaks when I got it. The biggest leaks were from the "bullet" that the speedo cable hooks to and the weep hole in the back of the yoke. Neither was terribly hard to fix.

New seal and o-ring for the bullet was just a couple of dollars, but hard to locate. I probably should have just gone straight to the dealer. I followed the directions for fixing the yoke leak in 73-87.com. I got the o-rings for it at the dealer. All of the auto parts stores tried selling me stuff that was just plain wrong. They must all use the same set of books or something.

It kept developing leaks, and I kept chasing them down. I finally ended up buying a complete seal set for it transmission. It was only about $30, and includes everything. No more parts to chase down.

I just replaced everything I could figure out, and that worked for a little while. Eventually the seal at the pump started leaking, and I had a transmission guy fix that using the leftover seals. I should have just had him rebuild it while it wa out. It is now leaking around the torque converter.

Slonaker

cliffsta · 12-21-2004, 07:06 PM

only about half a pint low, so not as big of a leak as i thought, i over filled it maybe a quarter of a pint Nov 7, so in the last month and a half its leaked 3/4 a pint, after that it usually tends not to leak much more.

12-21-2004, 12:01 PM	#1
cliffsta Stepsides RULE Join Date: Jul 2004 Location: Pineville, LA Posts: 1,921	tranny ghouls when i DONT need them. Well, my transmission might be takin a turn for the worse. It's started leakin ATF very bad, everywhere i park for more than 10 hours there is a nice sized puddle of it, and at my normal spot here at home, it looks like the wrekc of the Exxon Valdez. I haven't checked it in a week or two, cause i never really noticed it was all comin at once (i always park in one spot so there is a big puddle, but i just noticed the "new" spots) It's also getting real bad about not going into drive. Like backing up down the driveway and putting it into drive, it wont go, or it will start to roll forward barely, giving it the gas has no effect, and finally it LUMPS over into drive. Used to only do it once when first going, now it does it consistantly until the truck reaches operating temp. I gotta go get gas and when i get back ima check the ATF level, but are there any thoughts on how to stop the leak? My dad said he thinks its comin out the back, as he and my uncle changed the rear mains (if that applies or not, don't get us lying) and it doesn't leak oil. Also, is it just the modulator sticking that won't let it go into drive when it's cold? And long-term, how much generally does a tranny rebuild cost, or at least some solid maintenace? I know thats a bunch of vague ?s and its kinda long, but i'd rather learn now then, well, when i'm staring at a busted TH350C at a tranny shop... Thanks guys and gals, Cliff __________________ 1981 Chevy C10 Custom Deluxe Stepside 350 V8, headers, side exhausts, 3-speed auto SOLD 1980 Chevy C10 Custum Deluxe Stepside 305 V8, Edelbrock Performer Intake, Edelbrock 1406 600CFM 4-barrel, TH350C. Bent rod. SOLD 1984 GMC Sierra Classic Longbed 6.2L Diesel SOLD 2009 Kawasaki KLX-250S too many mods for this signature 1999 Honda Accord EX 4-cylinder, 17" Motegi Wheels 215/45/17 Sumitomo tires, Tein S-Tech lowering springs, KYB GR2 shocks, Acura TL 20mm rear swaybar, debadged, blackhoused headlights, Short-Ram Intake Cardomain of the Accord

12-21-2004, 02:32 PM	#4
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	The not going into gear problem is probably related to being low on fluid. If it is leaking that much, it will shift funny. Make sure the trans cooler lines are tight on the side of the trans. Also, check the seal on the dipstick tube to make sure it is not leaking from there. GM has an updated tube with a boot type seal and a locking dipstick tube to prevent leaks. There was a recall about transmissions building up heat and pushing fluid out of the dipstick tube. It would then land on the converter and burn the truck to the ground. you might check to see if the seal inside teh tailshaft is leaking. There is a weephole in the driveshaft of some trucks that will leak if the seal is going bad. I believe there is an article on www.73-87.com . Other than that, the only other places that I could think of that may be leaking are the front and rear trans seals. __________________ 1974 Jimmy- 5.3/4L80e/NP241

12-21-2004, 05:15 PM	#5
Slonaker Insert Witty Text Here Join Date: Oct 2002 Location: San Antonio, TX Posts: 3,415	I have a TH-350C that had a lot of leaks when I got it. The biggest leaks were from the "bullet" that the speedo cable hooks to and the weep hole in the back of the yoke. Neither was terribly hard to fix. New seal and o-ring for the bullet was just a couple of dollars, but hard to locate. I probably should have just gone straight to the dealer. I followed the directions for fixing the yoke leak in 73-87.com. I got the o-rings for it at the dealer. All of the auto parts stores tried selling me stuff that was just plain wrong. They must all use the same set of books or something. It kept developing leaks, and I kept chasing them down. I finally ended up buying a complete seal set for it transmission. It was only about $30, and includes everything. No more parts to chase down. I just replaced everything I could figure out, and that worked for a little while. Eventually the seal at the pump started leaking, and I had a transmission guy fix that using the leftover seals. I should have just had him rebuild it while it wa out. It is now leaking around the torque converter. Slonaker __________________ '86 Chevy C10 (Sold 04/19/13 ) Stock '01 Silverado

12-21-2004, 07:06 PM	#6
cliffsta Stepsides RULE Join Date: Jul 2004 Location: Pineville, LA Posts: 1,921	only about half a pint low, so not as big of a leak as i thought, i over filled it maybe a quarter of a pint Nov 7, so in the last month and a half its leaked 3/4 a pint, after that it usually tends not to leak much more. __________________ 1981 Chevy C10 Custom Deluxe Stepside 350 V8, headers, side exhausts, 3-speed auto SOLD 1980 Chevy C10 Custum Deluxe Stepside 305 V8, Edelbrock Performer Intake, Edelbrock 1406 600CFM 4-barrel, TH350C. Bent rod. SOLD 1984 GMC Sierra Classic Longbed 6.2L Diesel SOLD 2009 Kawasaki KLX-250S too many mods for this signature 1999 Honda Accord EX 4-cylinder, 17" Motegi Wheels 215/45/17 Sumitomo tires, Tein S-Tech lowering springs, KYB GR2 shocks, Acura TL 20mm rear swaybar, debadged, blackhoused headlights, Short-Ram Intake Cardomain of the Accord

12-21-2004, 01:41 PM	#2
leastbay Registered User Join Date: Jun 2004 Location: Lake Charles, LA Posts: 206	i have sort of the same question i am in the process of rebuilding my engine . My tranny leaks but i dont know where from but other than that it seems to work just fine its a th 350 would i just be better off getting a rebuilt one? or how hard is it just to change the seals..

12-21-2004, 02:26 PM	#3
dswancutt Registered User Join Date: Jul 2003 Location: Franklin, NE Posts: 387	Cliff; Try to wipe it clean as best you can to see where the leak is. It could be the front seal, tranny pan gasket, shifter input seal, tranny lines, rear seal etc. A little tranny fluid can make a huge mess under the truck. Low fluid will make it not want to shift. My 78 does the same, but can be real intermittent, some days it leaks, some days it doesn't, and it now whats to slip the first time I drive it. If you change the tranny pan gasket, I would suggest looking on eBay for a chrome pan with a drain. With a little bit of looking, you can find one for under $30.00 shipped to your door. Hopefully it is something minor. DO NOT USE ANY OF THE STOP LEAK STUFF. It's great if you going to sell you vehicle, but it will bite you on the butt latter on. I did this and it leaks worse now that it did before. I was quoted $550 - 600 dollars to rebuild a turbo 350 if I pulled it. Doug



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