Low transmission PSI in 94Q, am I in trouble?

[sandor]

I just went in for a routine flush and the machine showed transmission PSI at 35, the FSM (AT-87) says it should be at 65-71 at idle. It drives fine, but shifts a little sluggish when cold. Car has 127K, I did flush at 79K and pan drop myself at 85K. The fluid looked fine, is the line pressure different at the pan VS junction at radiator? Could their exchange machine measure the pressure differently than the FSM procedure?

Any help is appreciated.

[elwesso]

I just went in for a routine flush and the machine showed transmission PSI at 35, the FSM (AT-87) says it should be at 65-71 at idle. It drives fine, but shifts a little sluggish when cold. Car has 127K, I did flush at 79K and pan drop myself at 85K. The fluid looked fine, is the line pressure different at the pan VS junction at radiator? Could their exchange machine measure the pressure differently than the FSM procedure?

Any help is appreciated.

There are pressure check points on the transmission.. pressure would be much different at the cooler hoses...

[Q451990]

Where is this pressure check point? I always thought that the check point was at the radiator during a flush... I think it's possible that the gauge on the machine was defective though.

Heath

[elwesso]

ON AT-86...

1994 Q45 serivce manual..

[qship96]

what brand was the fluid exchange machine? I have used this procedure annually,and never recall seeing a PSI gauge or measurement taken during the procedure. did you time the flush to help determine overall health of the transmission? did they use a synthetic fluid or standard ATF?I just did q45techs 2 minute run-drain procedure this time around,as i am growing leary of letting the monkeys mess with the trans at this point{150,000 miles-so far shifts perfectly}.

[elwesso]

what brand was the fluid exchange machine? I have used this procedure annually,and never recall seeing a PSI gauge or measurement taken during the procedure. did you time the flush to help determine overall health of the transmission? did they use a synthetic fluid or standard ATF?I just did q45techs 2 minute run-drain procedure this time around,as i am growing leary of letting the monkeys mess with the trans at this point{150,000 miles-so far shifts perfectly}.

I agree... I am going to use this method too... 2 cases of M1 synthetic ATF and im good for a while.....

[qship96]

We[QUOTE=elwesso]

I agree... I am going to use this method too... 2 cases of M1 synthetic ATF and im good for a while.....[/QUOTE

Wes,I pumped 14.5 quarts of Mobil 1 through the trans,and figure for the $99.00 i saved by not using the machine,I can repeat my procedure every six months and probobly have a healthier trans than using the machine once every 12 months,and still save $ AND know there is NO damage to fittings,lines,or f-ked up engine sheild!

[elwesso]

How many Qts did you get out each drain?

[qship96]

first drain about 2.5 quarts,then about 3 per drain bt letting it drip for about 45 minutes-great to do if you are watching football or just hanging around the house for the afternoon!

[Q45tech]

35 psi at exchange machine is very good but that just shows the backpressure resistance of the rear planetary assembly and TC pressure.

The key is to time the exchange time at idle as the pump volume is around 4 quarts per minute = 3.5 minutes for 14 quart exchange [on a BG machine].

Over 4 minutes [after 15 minute warm up exercise while Quick Clean solvent is working circulating] indicates the start of problems [I have timed about :>50 flushes over the years and use a stopwatch to gauge the transmission pump health..............it works everytime. Bad - once it take 4.5>6 minutes [low ATF volume= bad pump seal/vanes or prior leaks before the pressure gets to TC.

Never really bother measuring other pressures as this method works well enough as really you have few choices [oem replacement or some EXPERT [not national chains] rebuilt] or live with it after multiple cleans flushes and Mobil 1 new filter new heat exchanger.

The valve body and solenoids [and other passages] are easily cleaned in place with BG Quick Clean solvent.

Reminds me almost Spring [4 months] time for transmission annual flush clean new ATF...........$100-200 is cheap for another years service! As I would still have to pay $1700 plus $200 for a replacement with my discounts.

[elwesso]

Dennis...

Level 10 specificically recommends to not use a flush machine. They said "it will wreck the seals"... etc...

I have about 18k on my M1 synthetic..... 30k on the transmission total, so the fluid has been changed twice... Would using the BG quick clean prior to the home made flush hurt anything???

[maxnix]

Level 10 specificically recommends to not use a flush machine. They said "it will wreck the seals"... etc...

I would be very suspect of any rebuilder that made this statement. BG just uses internal pump to move old fluid out to siamesed bladder to force new fluid in. Sun circulates using its own pump at rate of exchange similar to BG unit. Neither hurts stock OEM Nissan transmission by any creditable account nor by any evidence.
Modified by maxnix at 10:36 AM 12/15/2004

[Q45tech]

My 2nd transmission was BG flushed starting at 50k every year [1997-2003] [got a pan drain at 25k] for 7 times till I sold it with 185k, still in service in another Q with 213,000 miles been flush twice in new car so a total of 9 times.

Hogwash as to the flushing danger with BG machine and Mobil 1 ATF with BG conditioner.

BG Flushing is nothing more than changing all [most 95%] of ATF.

Now the solvent cleaner [BG Quick Clean] is another matter, but with care and proper proceedure it does no harm............the problem is shops are under time/money pressure -------to slam bam thank you mam.

Pan drops & filter replacements are the key -----get the worn material out fast before abrasion does it in............some kind of inline oil type filter sure helps as does a cooler.

If the ATF ever turns dark brownish flush the first time of multiple times without the cleaner/solvent.

We have some customer who pay for AT flushes at every other oil change every 8,000 miles [$130 twice per year.........we don't use BG cleaner every time depends on the look smell [taste] of ATF.

[elwesso]

when I made the post I was more/less referring to the BG quick clean stuff...

With 18k on the fluid (probably 20-22ish when I change it) and a fairly new transmission, i should be fairly safe, i think...

Ill use the BG stuff, run for allotted time, drop pan, and then do the DIY home flush...

The thing is... With the level 10 and the high performance ATF pump, it may pump more fluid , so the timing would be different.....

[Q451990]

I wouldn't do the home flush with the BG flush... you want to make sure you get all of that stuff out of there.

Heath

[Q45tech]

If the ATF passs the color test [white paper towel side by side with a drop of brand new ATF]................. you don't need a Quick Clean.

NEW ATF has enough detergents to clean varnish.............it's when you let the ATF degrade by running it too long or too hot that these additives are overwhemed or become useless by themselves changing chemical make up.

A QC every 2-3 years 30-45k should be enough if you change the bulk of the ATF every year ]or even two] depending on the color test.

When fluids change color or begin to wash out the color.......lighter and lighter less saturated red [in ATF case, or less clear/darker in other lubricants without dyes].............time to change them.

If you change oil every 90 days and others every year you don't have to worry about fluids [diff, atf, ps, brake/abs, coolant] when you stretch their life you have to worry..............7 year coolant HA HA..........life time fills mean short life times........diff might last 3 years depending on enviroment and how soon you want to pay $2500 to replace it.

Same with AC oil and dryers.......compressors and evaps are expensive.

Easier for me to just change all fluids every year then fluids plus gas filter are not on my mind. $400 is just 15% of the total M&R cost. Leaving $2600 for tires, brakes and prorated [60k services] repairs/replacements.