transmission flush debate

[elwesso]

This came up on another forum I belong at (Bet you cant guess!! )

Read the posts by Bbobynski- he is has been a powertrain engineer for GM for 30+ years... knows his stuff....

http://www.cadillacforums.com/...78535

For those of you that wont bother to read the thread (90%), I will give the cliff notes..

Someone brought up a post about flushing the fluid in his transmission at 52,000 miles.. Then all hell broke loose..

In summary, most people seem to think that back flushing the transmission is a really bad idea... Basically they say that most people wait until the transmission starts to act funky, and this usually means that its full of junk... Thus the fluid and machine gets infested with junk... So this way you can ruin the transmission...

However, they do like the idea of dropping the pan and changing the fluid.....

So techies what do you think??? I think our side and their side is legit... I dont know, do most places actually BACK FLUSH the trannies, that doesnt seem good, especially if you dont do a pan drop first!!!!!

[DAEDALUS]

No idea. If the transmission flush machine doesn't have its own pump, and relies on the transmission to move the fluid, then backflushing is impossible.

[elwesso]

Technically speaking the transmission flush machine would have to have a pump, because the transmission can only PUSH fluid, not SUCK fluid...

[DAEDALUS]

The BG machine has a rubber bladder with a floppy internal rubber membrane.......that costs thousands of dollars. The 14 quarts fills the bladder and every quart that the transmission pumps in, an exact corresponding amount of new ATF is sent into the return line.

There are shunt valves and inlet and outlet pressure gauges, pressure relief valves, drain valves, etc, etc .

You only need a PHD to work it properly. The secrets are not in the 1 hour training video tape.

Many transmission just dump the return line into the pan, Nissan does NOT that is the problem.

[elwesso]

Interesting stuff.. So the BG flush machine is basically safe...

Wouldnt you assume that nissan dealers use something like the BG OR EQUIVALENT???

[texasoil]

The flushing machine that was used on my 2 cars is great. It DOES NOT use any solvent , but exchanges the old fluid for new. It connects in the line going to the transmission cooler. Oil coming out of the transmission goes into the machine, and an equal amount of new stuff goes into the cooler and on to the transmission. There are clear flow tubes so you can see the old coming out and the new coming in. When the clarity is equal, measured by a light sensor, the machine switches into bypass and stops withdrawing/adding. The tech can then add or remove fluid as necessary to peg the fluid level using the machine.

This is as safe and sure-fire as it gets. Takes 14 qts to do a Q45. Both of mine (92,94) were in good shape, but fluid clarity difference was a surprise to me. Significant difference in shifting 2-3 on the 94. 92 has 40K on a high performance rebuild by super transmission tech here in Houston and still is crisp and snappy(but velvety smooth) on shifts at all throttle openings and speeds--perfect.

I cannot support using a solvent flush in an automatic transmission. If it has that much crud in it, chances are the transmission will shortly fail from clutch lining disintegration or lube failure.

[elwesso]

Texasoil.. Do you know of any places that use the machine that you refer to.....

I guess I would just ask for a non solvent, sort of "fluid exchange" flush machine...

[maxnix]

Sounds like the Sun machine supplied by Snap-On. Only mentioned 20 times previously by me. It does have its own pump and can be used to extract and fill PS fluid also.

[96QQ45]

They have one called T-tech they use at Jiffy Lubes and some other quick lube places. Works the same I think.

[elwesso]

So in essence what this is saying is that most placed dont actually BACK FLUSH the system... IMO that would be stupid, why would they do that?

[VA99Q45]

Remove the pan and replace the filter is more important than have the trany flush. I had my trany flushed and when I removed the pan I saw bunch of stuff on the bottom of the pan.

I think it is best to have the trany drain over night and then drop the pan and replace the filter.

[elwesso]

..... Doing this procedure instead of flushing AND doing this??

[texasoil]

By all means, drop the pan and replace the filter (actually a fine screen in Q45's) every 30K miles just to see what is there. Lot's of stuff (more than a haze of smoke on the pan) is like cholesterol in the arteries--tain't a good sign. If th eoil is far enough gone to leave sludge in the pan, just think what the fine passages in the valve body look like--essentially no flow to sweep things out.

Chunks means the transmission is terminal, on borrowed time,and needs a rebuild before it fails completely and demolishes expensive hard parts. More than a wisp of metal (small pea size in total @30K, less next times), or particles of metal big enough to see individually, is another bad sign indicating serious metal-to-metal wear--from planetary gears, clutch housings, bearings, thrust washers, etc.

The pan drop still does not exchange but about 20% of the total fluid. You still need the fluid flush job IMHO if you want the transmission to last 200K miles. If all you want is another year/10K why do anything?

[psychic_mechanic]

If the transmission is crap to begin with, a flush will just make it worse. The seals will shrink back in the new fluid and you end up with less pressure and more slipping than before. Always use factory or better fluid.

transmission flushes should be done at regular intervals, or at the very least when you first sart to notice a difference in performance.

Some guys have had luck putting limited slip additive in their trannies that are dying, at the least it should give you a couple more paychecks until it's time for a replacement.

[John Nordling]

OK, so which do you do first? A flush, or a pan drop and filter change? Any preference?

[Q451990]

Assuming the system is relatively clean, I'd go with the filter last. If the filter is already pretty full (in a dirty system) you might replace the filter before and after the flush. My preference is flush with standard AFT and cleaner first - then the pan drop - then flush with Mobil 1 ATF.

Heath

[elwesso]

I like the idea of a pan drop first regarless...... I wouldnt want all that stuff in the bottom of the pan being stirred around......

[j30freak]

Just had my J30 transmission flushed with the machine to get all of the old fluid out. Then I had them drop the pan and replace the filter (the gasket was also leaking), there was still stuff stuck on the bottom of the pan that they removed. Just a pan drop/filter change will leave a lot of old fluid in the system so I would say it's best to do both, not sure what the best order would be, but I had good luck doing the flush first and filter after.

[squeefoo]

I always drop the pan, put in a filter, clean the magnet and pan, reinstall, fill the pan with new ATF (about 6-7 qts.), disconnect the cooler line (I forget which one pushes -since the new cooler went on about 2yrs. ago), start it and purge into a bucket until the clean stuff comes out.Then I fill to the line while it's running and of course recheck after it's warm. The trans takes the clean fluid out of the pan and pushes the dirty out. Best way if you don't want to pop for a flush.IMHO

[elwesso]

Ill pay the money, its not worht the risk IMO. The back to the transmission line feeds the rear planetaires, and I dont wanna take a chance on those....

[SurfinGator]

I am posting here because at 110k, I had it done at a Jiffy Lube in Pensacola. My 92 was in excellent condition, I am the second owner and bought it from the original owner ... a couple in their 70s. I was looking to do the 120k maintenance and thought this would be smart .... wrong!

It ran fine for the trip back to Jackson MS, then the next week it started slipping into the higher gears .... torque converter? I took it to the Infiniti dealer here, Herren Gear, and the tech spent a half hour looking at it and told the service writer I had to replace the whole transmission. Fluid was over-filled, but the tech said that wasn't a problem.

So now I am looking at dropping the pan and replacing the filter at a REAL transmission shop .... and if they say its toast there goes my cash ....

all because I flushed my tranmission at a Jiffy Lube.

[Q45tech]

Don't blame them totally as YOU chose them.

Just like owners who take their cars to GENERIC shops, every time I hear PET [p] BOYS, I cringe [Doug at T3 served as an asssistant manager at their most profitable location for years......the horror stories].

Letting someone not certified in your car brand work on your car [if a rare model] is YOUR fault pure and simple.

There is a pressure vent atop the transmission to blow out excess ATF if over filled beyond a safe level.........10% [a quart] is not significant.

More cars are destroyed by owner neglect than incompetent technicans.......most at shops know when to give up, but people who work for low wages may not have the understanding of the dangers.

[maxnix]

I would think a first flush at 110K miles without a pan drop and clean followed by a filter replacement is not a good practice.

There are other stories of Q45 transmissions seizing from ATF starvation when the filter screen becomes clogged with previous and newly loosened debris. Pan drop, clean and filter replacement is mandatory every other flush.__________________Brian1995 Q45 & Q45t & 2000 Q45

Discover the power of the button!

[lfootmatt]

How about this plan.

1) transmission fluid oil analysis, shows clean with absolutely no clutch pack materials(copper & lead), all others also much better than acceptable.

2) Drain & drop the pan

3) Overnight drain

4) new filter, gasket & top off with Mobile 1 fluid. And conditioner? Dosen't Joe pack a bottle of something with his filter/gasket kits?

5) At each oil change drain transmission from plug and top off with Mobile 1 ATF

6) Annually start at #1

I'm a firm believer in annual (and any car, boat, RV, etc. purchase) oil and transmission fluid analysis.

A good lab can baseline your component and give you predictive information on the condition of you engine and transmission.

This technology is mostly reserved for industry where thay are running huge diesel engines that cost more than our cars do. Of course they also want to reduce costs, so they use the analysis to determine fluid change intervals.

does anyone think this would be a good alternative to the flush machine.

On the BG machine, how much pressure does it exert on the new fluid being pushed in from the bladder to the return line and rear planetary gears?

According to Q45Tech the return needs to be around 20-25 PSI. If the BG machine matches the incoming PSI and flow rate then this shouldn't harm anything if you have a clean pan and filter to start with. I wouldn't want to run the new fluid through a cruddy pan and filter!!! thaqt would seem to defeat the point of the new fluid.

I think if I do the BG Flush I will make the tech show me the machine, how it works, the flow paths, and convince me that indeed it is only pushing new stuff in and that it does so with the proper pressure and flow rate. Of coures I'll play dumb the entire time to see if they are going to try to scam me.

BTW, what does Scottsdale Infiniti use. That is where my J30 was done before. Any way to tell form the records if it was flushed or just a pan drop? When did they get a flush machine and what kind is it?

Thanks, Matt

[Eswift]

They have one called T-tech they use at Jiffy Lubes and some other quick lube places. Works the same I think.

yes they do, and the machine is great - ive used it myself. Did a flush on my j30 when it had 80k miles (no transmission service ever before that) and it is still hauling at 105k. really easy to hook up, 20 min job.

You do always have to worry about Jiffy Lube though,

I have personally seen cars sent off with 4.25 quarts of ATF in the engine, as well as without any oil at all.

[SurfinGator]

Don't blame them totally as YOU chose them.

Just like owners who take their cars to GENERIC shops, every time I hear PET [p] BOYS, I cringe [Doug at T3 served as an asssistant manager at their most profitable location for years......the horror stories].

Letting someone not certified in your car brand work on your car [if a rare model] is YOUR fault pure and simple.

I am with you .... I have been using this same Jiff Lube off and on for 5 years to do my oil. Why I made the leap of faith that they could do ANY kind of transmission work I have to say it must have been a brain FART!

PEPE Boys sux! I have had them cut CV boots and loosen battery terminals trying to sell work someone didn"t need ... well, until they came into Pepes.

Infiniti is doing the trannsmission repair ... found a few "transmission shops" that were less .... but I am not playing with this.

[96QQ45]

Absolutely be wary of Jiffy Lubes. I had my t-tech done at a quick lube place that actually has an ex-Jiffy Lube manager. He left because the company doesn't have any way of dealing with someone that actually knows what he is doing-all are treated like the children that most are. He's a good mechanic who ran his own service station for years.

Anyway, I only go there because I know him and trust him. If you just drive into any Jiffy Lube for service you are rolling the dice big time. I worked for the largest franchisee of Jiffy Lube and the damage claim payouts are over 2 million a year... No oil filled, over fills, fluids in wrong components, trannys, tires falling off...

[ardvarkus]

Infiniti is doing the trannsmission repair ... found a few "transmission shops" that were less .... but I am not playing with this.

Anybody else uncomfortable with the thought of a dealership doing a 'local rebuild' on a transmission?

If they are just installling a factory reman, fine- but they probebly have even less rebuilding experience than a transmission shop (although perhaps more with that specific model.

A

PS Joe is selling factory remanned for 1850 plus shipping...

[wlong]

I just did a drain and refill on my transmission (~1 gal) at 90K. I wanted some new fluid to clean the system before I drop the pan and change the filter. Any idea how many miles I should drive before I do the pan drop? I want to end up with a clean filter when I convert to Mobil 1 ATF - hopefully before the summer heat hits. I was thinking that several hundred miles should do it.

W. Long96 Q45

[Q45tech]

Drain and fill at every oil change might be excessive but it is cheap.........and fast. We use clearish giant gallon distilled water bottles to measure the drained amount.

The ATF circulates at 4 quarts per minute so......so 2.5 times 10= 25-30 minutes at highway speed should be as good as it gets about mixing fluids.........think you might be optimistic in how new ATF cleans old ATF or the transmission.

The BG Quick Clean for transmissions Additive is allowed to circulate 15-20 minutes........the strong smell quickly dissipates, so it is either evaporating [out the vent] or changing as it reacts with the varnish and clutch material [not the glue]. After the transmission heats up, the the BG machine fluid exchange.

"Machine Flush" causes all sorts of semantic problems as people assume wrongly the machine does the flushing when it really is just a dual container.