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trans flushing; good or bad?

M

moparjim1987

NAXJA Forum User
Location
pennsylvania
my 97 cherokee has about 164,000 miles on it and as far as i can tell the trans hasn't been serviced. i am contemplating either a filter change and some new fluid, or just a trans flush with the cleaner and conditioner added. I'm not sure what model trans it is but it is the four speed auto that you can't hold in first gear unless you are in low range. i would like to do something before it goes out on me........its just my luck.:(
 
I would also stay away from a flush. The best thing you can do is to change the fluid and filter. If i remember right, you should be able to clean the filter on a Aw4, wich is probably what you have. If it has never been done, i recom'd changing the fluid out and then maybe 5,000 miles,,,do it again.
 
I've flushed tranny's for at least 5 years... I have yet to see or hear on a real life experience were a flush has damaged a transmission. It is urban legend as far as I can tell. There is the possibility of a cleaner causing some seal problems, but I have yet to see that either. Although, I have only used BG's cleaner.

I have yet to see a machine that uses higher pressures then the transmissions pump is producing, so unlike many people think it's not really pressure washing the insides of the tranny.

The filter is a screen, so unless you have big tranny problems a cleaner and flush would probably clean out any debris that is in it. If there is much stuff stuck in the filter, a clogged filter is the least of your problems.

To me, flush is bad terminology. Everyone thinks you are using high pressure to push out the fluid and clean the tranny. I prefer the term fluid exchange. Because all you are doing is replacing all the old fluid with new. The cleaner will be completely out of the system with the 12-16 quarts of new fluid pushed through, so you cannot even argue that it may stay in the system and cause break down.

Keeping old fluid in there will cause more problems. The fluid lubes the inside of the tranny, there are bushings, bearings, gears, etc... that all need clean fluid to keep the lubed without damage. All new fluid will be better on those components then used or mixed used and new fluid, no if's, and's or but's.

I'd personally would not hesitate to have any local lube shop do it, if you want to be cautious, tell them no cleaners or additives just normal DEX/MERC III fluid like they will be using anyways. Or if you are really paranoid go to a dealer that uses BG equipment and chemicals, most new car dealers probably are BG dealers, at least here they are.
 
I don't rec a flush on anything over 100k unless you know the service history. I have used BG for years, and no, I havn't seen any issues with them however I have been using newer equip with moc products and have seen two cars in the last 14 years that never left the bay once flushed....both higher mileage. The above statement is correct. It's more of a transfusion than a flush...out with the old...in with the new. The equipt I use transfers fluid utilizing the trans pump, so pressures aren't that high, but on higher mileage trannys there is a chance that it will break loose friction material residue from between the clutches/friction plates....causing slippage. This is very rare, but possible, and if this were the case than the tranny was on it's way out anyway. I don't rec any conditioners or cleaners either.

...just change the filter and fluid....no "flush".....just my .02
 
I had mine flushed at 166K with no prior history known on the rig. It's been running like new since and took care of slippage it had when it was cold. I took it to a shop that dealt with Toyota's and knew how to flush the AW4.

I bought the rig with 165K on it and since the flush have put another 10K on it. A couple of distance trips from Oakland to LA with some wheeling thrown in along the way, four Pismo trips where it was driven from Oakland to Pismo and back, camping and wheeling up at Lassen, ...

If you have a shop that knows Toyota's or Lexus talk to them about getting the trans flushed. They would be the best bet since they will have more knowledge with the AW4.
 
Both the moc and the bg machines are universal....they hook up inline with the trans cooler lines, so it doesn't make a difference who does it, unless they plan on rebuilding it for you in the event that something goes wrong. My shop made the 100k policy after we bought those two trannys....although two in 14 yrs is not bad...considering we probably do 20 or so a week.....all I'm saying is be aware that something could go wrong.
 
redsand187 said:
I've flushed tranny's for at least 5 years... I have yet to see or hear on a real life experience were a flush has damaged a transmission. It is urban legend as far as I can tell. There is the possibility of a cleaner causing some seal problems, but I have yet to see that either. Although, I have only used BG's cleaner.

I have yet to see a machine that uses higher pressures then the transmissions pump is producing, so unlike many people think it's not really pressure washing the insides of the tranny.

The filter is a screen, so unless you have big tranny problems a cleaner and flush would probably clean out any debris that is in it. If there is much stuff stuck in the filter, a clogged filter is the least of your problems.

To me, flush is bad terminology. Everyone thinks you are using high pressure to push out the fluid and clean the tranny. I prefer the term fluid exchange. Because all you are doing is replacing all the old fluid with new. The cleaner will be completely out of the system with the 12-16 quarts of new fluid pushed through, so you cannot even argue that it may stay in the system and cause break down.

Keeping old fluid in there will cause more problems. The fluid lubes the inside of the tranny, there are bushings, bearings, gears, etc... that all need clean fluid to keep the lubed without damage. All new fluid will be better on those components then used or mixed used and new fluid, no if's, and's or but's.

I'd personally would not hesitate to have any local lube shop do it, if you want to be cautious, tell them no cleaners or additives just normal DEX/MERC III fluid like they will be using anyways. Or if you are really paranoid go to a dealer that uses BG equipment and chemicals, most new car dealers probably are BG dealers, at least here they are.
Click to expand...

well here's your first: I had one of the "jiffy shacks" do a flush on my Chevy S10 at about 85K miles, afterwhich, when I towed my undriveable truck to the transmission shop, he explained to me it was the high detergent ATF running through the dirty, tired old tranny that doomed it, he told me had I changed the fluid and filter from the pan, slowly over a period, that would not have happened. This was 1998, on a 96 truck
 
well here's your first: I had one of the "jiffy shacks" do a flush on my Chevy S10 at about 85K miles, afterwhich, when I towed my undriveable truck to the transmission shop, he explained to me it was the high detergent ATF running through the dirty, tired old tranny that doomed it, he told me had I changed the fluid and filter from the pan, slowly over a period, that would not have happened. This was 1998, on a 96 truck

HMMMM an electronic version of the 700R4. Not a very reliable transmission to begin with. Definately does not like towing in OD. As far as the AW4 I'd suggest changing pan and gasket with the filter. If the fluid is good leave it well enough alone. If not then flush it. Do not let them use anything but Dexron 3. Many quick lubes are wanting to use the additive to the newer trans fluid, do not let them use that fluid. My 94 has 130,000 , and I've beat the daylights out of the transmission from towing and four wheeling and can say these are very forgiving transmissions as long as the right fluid is used and you not tow in overdrive.
 
Geeze, you lazy auto tranny guys, all I have to worry about is getting the correct GL3 for my AX5 and 15's but then now since we picked up the ZJ we do have one auto in the family. I am going to change that out this spring or early summer, the slow way, a pan at a time.
The flip side is I am looking at other options like converting that chrysler tranny into an AW4 or going whole hog and converting it to a 5 speed which is doable in the 97, it runs a XJ ECU so it would not be a big stretch to change the ECU to a manual ECU to eliminate the computer input from the tranny, not to mention that holes are already in the firewall for the clutch master cylinder and the parts for the manual GC's are available.
 
Yup, lots of good information here. Flushing a high mileage AW4 does not guarantee you're going to have a problem but just be aware that it CAN happen. There is more than antecdotal evidence of this in the industry. Is it kind of rare? Probably (agree with Spd9075 on this) but remember that Murphy's law is alive and well.

With the cost and hassle of a swap/rebuild, a lot of guys just drain fill when you have that many miles on the tranny/fluid. Neighbor has an independent tranny shop and over 30 years experience, that is his view as well.

IMHO, I agree with drain/refill if the fluid has over 100k on it. Then repeat after a few thousand miles. Just like shampooing your hair except skip the lather part.....

OR, flush and roll the dice and hope that it all works out! To each their own!!
 
i am a auto technician 12 years in the field,Transflush will be just fine.My shop also uses the bg products good stuff no gimmick. just use what the vehicles owner man calls for .
 
I work for BG products, I can tell you not all chemistry is the same and the jiffy shacks that do use chemistry on average don't use ours, the go with the cheapest product available which will usually do nothing good if any for you transmission. It is actually safer to do a flush than a drain and fill the new fluid and old fluid will not mix basically giving you a "black and tan" type of situation and the fluid will ot mix and work properly together. check out www.bgams.com to see a video on the service. or www.bgfindashop.com to find a local place that offer that service

Also in CT we do business with alot of the Jeep Chrysler dealerships
 
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