NorTown Olds

Greetings All,
Need some advice here; I've read several of the old posts on "How-To" Drain the tranny, replace filter etc. Periodically, or whenever I first get a "New Old Olds" I'm normally a drop the pan, change the fluid & filter and even disconnect the coolant lines to get as much old fluid OUT as I can and replace with new; preferably AMSOIL Full Synthetic Fluid.

BUT, I've recently bought an '83 Ninety-Eight w/ just barely 40K Original Miles on it and I WANT to change it but some guys locally are swearing I need to have a GM Dealer or Professional Tranny shop FLUSH out the transmission to get everything "cleaned out"...THEN, later I guess I could drop the pan, put in the new filter and add my sythetic fluid...or would the tranny shop do that?? (Is this "FLUSH" now standard when servicing transmissions??) I intend to keep this cream puff Ninety-Eight for a LONG time but I want to do it RIGHT by that original tranny! Those were "subject to early failure" back in the day due to all the plastic parts and stuff they had...want to be as Preventive as I can be on my maintenance.

Thanks for the advice/opinions as always...

67 Cutlass Freak

IMHO the flush is the way to go. That service is supposed to be done every 30,000 miles, and filter @ 100,000. When you drop the pan you only get 1/3 of the fluid out, even if you drain the lines. Torque converter and the valve body hold the other 2/3. Check around for a local Valvoline quick lube center. Most have a flush machine, and they use Valvoline synthetic ATF that is widely compatible. The shop I'm working at has a flush machine, with our service we run a cleaner through it first for 10 minutes to free up any deposits stuck in the veins of the torque converter. Then we flush and then we put in a friction modifier in for the last step. We do a ton of them, and the service sells for $119.95.

NorTown Olds

OK, sounds good and makes sense! I like that Valvoline Synthetic deal What shop do you work at?? (I want to get ALL or as much of that old fluid out as possible...so sounds good!)

ah64pilot

I would only do a flush if they are changing the filter as well...a flush is going to loosen up all sorts of crap (if any) and lodge it in the filter. I personally don't like flushing a transmission, I used to work at Jiffy Lube, all we did was hook up to the cooler lines and push new fluid in. I see no benefit in forcing fluid through the transmission without changing the filter...

Aceshigh

Not only the filter, but any small passages could get clogged due to the pressure loosening up all debris at once.
Flushes have caused more customers to come back complaining about trans malfunctions after a flush as a result.
Those that were fortunate enough to not have this happen to them, think they work great.

Buddy of mine is a transmission shop owner.
He's been in business for 25+ years, and he doesn't recommend doing it.
However, you will get varying opinions on this from each and every trans guy you ask.

A large portion of the trans fluid is in the torque converter.
You're not going to get all that out.

67 Cutlass Freak

I work for Waukegan Tire in Northern IL. Some of the opinions about how the trans flush process is actually done, and how it
"stirs up ****" are a little unfounded.

Most current vehicles manufacturer recomend a filter change @ 100,000 miles or not at all. The filter on most foreign cars consists of a metal screen. I have never seen one clog. If you don't maintain your vehicle, and flush it every 30K, of course your filter should be changed.

When the vehicle is being "flushed", this does confuse some people because they invision their trans being flushed under high pressure. A better term for the process should be "transfusion". The vehicle is running, that pump in the transmission is the only thing pressurizing the system while the vehicle is hooked to the machine, being flushed. Same exact pressure going into the machine as that coming out.
The biggest problem happens after people have 150,000 miles on their car, and they start having a "minor slippage" problem. They think to themself- "I must need a trans flush". Absolutely never flush that trans, you may not be able to back it out of the shop. I've been doing them for twelve years and I really believe in them for maintenance purposes. It is not designed to fix your transmission problems.
Changing the filter every time IMHO is not necessary. If your racing, or just want to get a little messy under your car, do it. It's real easy to swap out the filter on most vehicles. Their are some vehicles we cannot flush. No dipstick, some Saab, Jag, VW, Audi, Mercedes all the real odd *****. I've seen a couple cars with extremely dirty trans fluid with under 20,000 miles. They were both Hyundai. I don't push this service. It sells itself to people that really want to maintain their ride. Most people right now can barely afford to keep their car repaired let alone maintained. I recomend you talk to a couple reputable transmission shops and get their opinion. I think the first words out of their mouth should be, "what is your year, make, model and how many miles have you got on it?" Some tranny shops might tell you never to flush primarely because they need your bussiness. They're bankin' on your trans failing.

NorTown Olds

THANKS ALL! (Man, did this open a can of worms or what?! ) Lots to think about here and lots of variables. The car only has 43K original miles on the original 307 V-8 Motor and standard OD Transmission; nothing has been done to it as best I can tell....I want to KEEP this car a long time and maint it as best I can....Hence, desire for a flush or "Transfusion" as was aptly said -- I figured later, I'd drop the pan and change the filter too. (Flush NOW and after Winter/Spring I'd put the new filter in etc.)

ah64pilot

Let's assume said car has a 30 year old HYDRAMATIC transmission with a paper filter encased with metal. I would not compare it to "current vehicles". I'll stay my opinion that this should be maintained as the manufacturer intended with transmission drain and filter change. If it was electronically controlled and pressure variables didn't control shift points, I would have a different opinion.

Aceshigh

Just remember something.....

These cars only had a 5 digit odometer.
It's only showing 43,000 miles but if it had a 6th digit.....who knows....143,000, 243,000....etc.
It could have been garaged and driven alot for all a buyer knows.

Just keep that in mind when shopping for cars from the 80's and earlier.
My odometer reads 7,651 miles on my 1970 Olds 442 clone.
There's no way in hell it was only driven 7,651 miles.