Question? what’s the type and quantity of transmission fluid for 1970 Oldsmobile Rallye 350. What’s the pounds the bolts should be when putting pan back? Do I need to add gasket sealer on gasket?

Thank you 🙏🏻

 

I just did mine on my 70 supreme 350/350. About a gallon of dexron II. If you can find it. I have a bunch of III at my work since older Gleaner combines take it and few 40 year old New holland skid loaders take it. You will end up with a Dexron/Mercon at most auto parts. Or you can go to a GM dealer and get Dexron VI

I torqued the pan bolts at 18 lb/ft. You should not use any type of sealer. I used gasket eliminator in a about 8 spots to hold the gasket while tipping the pan back into place past the cross member.

Pat

 

I appreciate the (HELP) Information

 

Before installing the pan make sure the bolt holes on the flange are flat & not bulged from previous over tightening. If there is deformation use a small hammer w/ pan flange on a flat surface to flatten them.

I hope that makes sense, the wording is not a literary work of art!

 

I appreciate the EXTRA Information , Very Smart I could have something going on because I do have wetness on the Pan .

thank You

 

Is this OKAY to use?

Thank You..

 

Yes. It's a synthetic and a bit more expensive but it is fine to use w/ your transmission.

 

Thank you Vintage Chief. that makes me feel much better..not the price but its good to use.. LOL

 

The manual calls for 120 in/lbs, which equals 10ft/lbs of torque. As mentioned before, make sure the pan is flat. A little dab of silicone is ok to hold the gasket in place, but usually isn’t necessary.

 

Matt69olds how much of Transmission fluid should I add? a gallon?

 

I don't recall "exactly", but I don't believe you're going to lose an entire gallon (4 quarts) of ATF when changing only the transmission filter. The majority of the ATF will remain in the torque converter (~5 quarts) and inside the transmission itself (~1.5 - 2 quarts) if I recall correctly. The THM350 transmission capacity is 10 quarts. Therefore, adding one gallon (4 quarts) might be borderline on overfilling the transmission; and, you do not want to overfill the transmission.

It was my understanding from reading your previous threads you owned the CSM for your vehicle? The capacity for the transmission is listed in the MAINTENANCE section in the front of the CSM. Be certain to follow the CHECKING TRANSMISSION OIL LEVEL contained in the 350 Turbo Hydra-Matic section of the CSM. Follow the procedure exactly as stated.

Error on the side of caution. By this I mean to say do not overfill the transmission when first adding ATF after you have changed the filter and lost some transmission fluid in the process. Add smaller amounts of ATF initially - bringing the ATF oil level up slowly.

If you require further assistance (other than what is listed in the CSM), we can walk you through the process of checking the transmission oil level and measuring the level on the transmission oil dipstick marks for ADD and FULL. If you overfill the ATF will begin to foam and you'll bleed ATF out the vent pipe for some time.

 

I have added the 4 quarts already in one shot, car has not been started since I got it in garage, should I try to remove some? you got me worried now.. I forget where but someone said just to add a gallon..
thank you for helping me.

 

I am off to play golf and can't respond further on the measuring marks on the dipstick - others will most likely respond. You'll be fine if you overfilled, it will dump out the vent pipe (for quite some time) or you can remove some (depending on whether you did overfill). If no one has responded in 4-5 hours I can point out the COLD versus HOT (ADD & FULL) marks on the ATF dipstick.

 

If you did overfill it, loosen a cooler fitting at the radiator. Put a drain pan under the cooler line, start the car, and let it idle a few seconds. Check the fluid, either tighten the fitting and top off the level, or drain some more.

 

As Matt suggests (^above^) in case you did overfill.

Below is the proper method to check your ATF level on a THM350.

 

BTW, if you do not own the 1970 Oldsmobile Chassis Service Manual (CSM) you need to step-up your game.

 

On what page did you get all that information?

thank You

 

CHECKING TRANSMISSION OIL LEVEL - TRANSMISSION 350 Turbo Hudra-Matic
1971 Oldsmobile CSM, pg. 7-204 (pg. reference may vary for the 1970 model yr.)

CAPACITIES - All Series PERIODIC MAINTENANCE
1971 Oldsmobile CSM, pg. 0-15 (pg. reference may vary for the 1970 model yr.)

Developed by Chevrolet & Buick, the THM350 transmission was introduced in the 1969 model year as the successor to the GM Powerglide automatic transmission. The THM350 remained basically unchanged (there were some variances in bolt patterns) until 1981, when an electric overdrive solenoid was added and the transmission was renamed the TH350C.

 

this is what I see in my CSM??? Do i have the right book?

thank you

 

You guys are probably one year off. I think chief is showing you a 71 manual.....Hondo, you have a 70 manual. And, happy late birthday.

 

 

First I heard to put a gallon, so I added 4 quarts then someone says put 3 quarts, so I got worried and used tube to suck Transmission Fluid out using gravity, took awhile but I took out 2 quarts. so I can run the car and check it, after filling it up one quart at a time.

 

Not an "overdrive" solenoid, a torque converter clutch solenoid. Also requires the clutch assembly in the torque converter, the various seals and passageways, etc.

Ideally, you'd have dropped the tube at the trans cooler that routes the cooled fluid back to the trans. Install a "temporary" tube into the cooler, with the other end in a drain pan. Put 5 quarts of fluid in the pan, open another five or so quarts. Have someone start the engine while you pour the remaining fluid down the dipstick tube until the fluid coming out of the cooler is as clean and bright-red as the fluid you're adding. Shut off the engine, re-connect the cooler tube, start engine and top-off fluid as needed.

You've just changed ALL the fluid in the trans, except for a miniscule amount trapped in the valve body and clutch packs.

For the record, "most" pan gaskets have a few bolt holes that are smaller than the rest. (Or they're all small) If you poke a bolt through the pan and through the gasket, the gasket will "hug" the bolt and that keeps the gasket nicely aligned during installation of the pan. NO need for sealers/glues/silicone/etc.

 

Just did this last weekend on my 68 with a th350, left it to drain overnight and measured the actual amount, 6.25 qts drained into my catch basin. That's how much I put back in....