montie98

Whats better, when the pan is dropped or the new service I see alot of places doing where the pan is not droped but the Transmission is flushed through the lines?I have been told that the flush is better because it leaves absoulutly no old fluid in the trans. But what about leaving the old filter in?

bogus

it leaves the filter in only to help filter the pumped stuff.

I would pump it and replace the filter. the best of both worlds. :thumbs:

ninetyfivevette

I thought I read not too long ago on this forum that Walmart discontinued "power flushing" because it could damage the transmission somehow. Hopefully someone smarter than me will chime in!

86PACER

:lurk:
I recently dropped the pan and filter in my garage. It had been a little over a year (25k) since my trans rebuild and the fluid looked and smelled like new fluid straight from the container. I added a B&M drain plug while the pan was off. And I installed a B&M Trans Cooler for good measure. I did not want to pay someone $100 plus to flush and fill my trans.

drvette85

I also was told by a tranny shop NOT to power flush because it was had for the seals of something??? Not too many tranny shops carry the power flush machines out here. Seem like just the quick qil places carry them.

:lurk:

Mr Mojo

It has been discussed many times on this forum, do not flush the trans. Almost everyone who did came back on here with bigger trans problems. I don't remember any specifics.

rocco16

The advantage of the flush over the drain is that flushing will change the fluid in the torque converter, while draining will leave the old fluid in the TC.
Seems like a low-pressure flush (if there is indeed such a thing), combined with the drain so that the filter is renewed, would be the ideal.

Larry
code5coupe
:seeya

lspalding

I do the flush on all my cars every 30k. It has worked out well. Did both services when I first got the '89 since I didn't know the history.

A friend just took his car in to my mechanic and they did a 'drop the pan' service. Would not do the flush. Apparently the trans had not previously been serviced in 100k miles and was filthy inside. They said that to replace all the fluid would put too many fresh solvents in the system and result in problems. He'll be looking at a rebuild fairly soon.

Just reinforces my idea in my mind to keep it fresh in there.

blk90rdstr

The biggest problem with failure after power flushing a trans is a lack of maintenance. I have been told not to even service the trans at all if it has been neglected for over 50k. Flush guys tend not to do the filters either. A rip off at 60-100 dollars. If your good with scheduled maint, its best to pull the pan change filter and gasket, plus it gets you under there to look at other stuff.

War Machine

I had mine flushed @ 70k miles and it didn't do any harm. I'm not sure how well maintained my '87 was, I assume not very well since carfax showed 3 emission failures prior to me buying it. I still prefer the method of dropping the pan so the filter can be changed.

mackeyred96

PAN :thumbs:

1990CORVETTE

I did a flush on my tranny 700R4 and it made it worse,,,, $2,400 later,,,,, i am now satisfied :D

HeeHaw89

I dropped the pan at 115k miles, replaced filter and topped off fluid until full. Its the original unit now with 125k miles that is still laying rubber on the 1-2 shift.:D
It is true that a full flush could possibly make a higher mileage tranny worse.
I actually hope my tranny goes soon. My convertor is a bit too loose for my taste and I'm not going through with the trouble of having it re-stalled by PI until the trans needs to be pulled anyway.

mphy98

i work at an auto dealership, ford chrysler dodge,and merc. i had my 90 flushed with the machine, it now has quicker shifts. dropping the pan only gets out the pan fluid, this does it all. the filter is backflushed too, so it doesn't need changing. a couple of the techs that i have known for years are very high on this machine, one has a vette himself and has done his own. i suspect the sour grapes coming from small shops is that they don't understand the technology yet. mine has118k on it and the flushing hasn't hurt it one bit, and seems to have helped. :cheers:

comp94

the 700R4 tranies are very finick. some times you get a good one and somtimes you dont just the luck of the draw i guess. the 700r4 in my truck has 200,000 miles on it know and i dont think that it has ever had the fluid changed while the 700R4 in my farthers truck lasted 130,000 miles.

sraft

I don't believe that flushing is bad, but you can't indefinately postpone filter changes. As the clutches wear, the residue ends up in the fluid and is trapped by the filter. At some point, if never serviced, either the filter will clog and/or the fluid will saturate with the debris which will accellerate the wear on the internals and seals.

I think that this is what happened to my daily driver, which had 165K miles on the tranny and had never been serviced. I had to have it rebuilt because the front seal went bad and was leaking about a quart in ~300 miles, although the tranny was otherwise operating just fine. As a desperation measure (before the rebuild) I dropped the pan and did a filter change. The fluid was real dark and a little gritty but did not smell burnt at all (which indicates that it never overheated). The grit was not metallic and there were no metal filings on the pan magnet, so I'm pretty sure that the grit was the clutch residue. It probably acted like a lapping compound and chewed up the seal(s).

cduckworth

Some of this terminology is a bit confusing. To change the filter, clean the pan, and change all (or nearly all) of the fluid, try this: http://www.partshp.com/FluidChange.htm

Simple and works well.

darkman5001

Emmision failures! What do you mean? CarFax shows that stuff? What else does it show?

OleDog

You really should do both. If you don't want to get under the car to drop the pan and change the filter at least flush it out yourself(have a shop drop the pan and filter). Very simple and you won't even get dirty. I'm thinking there's a tech article on it. I know I did it myself last year, It couldn't have taken more then 20 minutes with no mechinacal skills. If you can't find anything EM me and I'll see if I could find the notes I took for myself. If I remember correctly the pan holds around 4 pints and the trans holds 13pints.

darkman5001

I change my fluid AT LEAST every 30,000 miles, and I do the drop-the-pan method. I ALWAYS chage the filter too. Who wouldn't you change it? :confused: It only costs $15-20 but it is filtering all the crap out of the trans. Think about it! If you have a Vette, or a nice car, then why do everything the CHEAP way. Keep it all new, and fresh, and pay special attention to details like that, and the car will last forever. I changed the fluid on my 94 explorer also at least every 30,000 miles, and I have absolutely NO problems at all. It has 167,000 miles on it. I treat the engine the same way, new sensors and all, and it is perfect.
:cheers: