Transmission Fluid Exchange Writeup (1 Viewer)

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So I finally got around to swapping out the tranny fluid in my '96 80 with the A343F. I bought twenty quarts of Amsoil Universal ATF and called every shop in the area to find one with a transmission powered fluid exchange machine like the one used by Christo and American Toyota. Unfortunately no shop had one of these and most did not even know these things exist. So after much reading I decided to try another approach. I ran the truck to warm up the transmission and then went through all the gears before I simply disconnected the bottom line going to the transmission cooler (near the radiator) and used two pieces of tubing to extend the this line and the male end of the tranny cooler itself. I put both of these tube ends in a clean five gallon bucket and started the engine with the transmission in park. Fluid then flowed quickly out of one of the tubes and into the bucket. As soon as it started to sputter and blow air I shut the engine off and refilled the transmission with approximately the same amount of fluid that was pumped into the bucket. I refilled through the transmission fluid dip stick with a very narrow tipped funnel. I then started the engine again and repeated this process several times until I could visibly see and smell the clean Amsoil flowing into the bucket. In the end the five gallon bucket was almost full (five gallons = twenty quarts) and I had gone through eighteen quarts of Amsoil Universal ATF.

Observations:

I bought the truck used with 70K and now have 90K. I do not know if the transmission fluid was ever changed before but it was extremely clean if it had 90K on it.

Be sure that the hose clamp for the cooler line is seated properly as these tubes sometimes need to heat up to re-create their initial seal.

I've only driven short distances so far but I swear that the truck shifts smoother. In fact I could not even feel the shift into overdrive and had to repeat this shift several times as it was so subtle.

Overall this procedure was very simple and according to my research much better for the tranny than a flush. For those of you without access to a fluid exchanger ala Christo, I would recomend this simple process.
 
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Expensive...yes. But so is a new tranny and as I said I do not know the history. A tranny crapping out on you 3000 miles from home is expensive...the Amsoil seemed like a deal to me and not as bad as I thought at $5.90 a quart. I just won't be drinking that expensive beer for a while. Cheers
 
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Just curious why did you extend both lines? Just so it could drain either way? Or did you not know which way the fluid flows (I don't), just curious.

My dad did this same thing on his Ford van he just drove across the country WAY overloaded. The tranny pan on that has no drainplug, so it was either pull the pan or disconnect a hose, we did the hose and same start/shutoff thing, worked great.

Did you try to shift through any gears while you were spewing fluid and the engine was running? I'd try to get as much as out as possible, but not damage it during the swap, I guess a fine line there.

Good job though!
 
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snowcruiser said:
So I finally got around to swapping out the tranny fluid in my '96 80 with the A343F. I bought twenty quarts of Amsoil Universal ATF and called every shop in the area to find one with a transmission powered fluid exchange machine like the one used by Christo and American Toyota. Unfortunately no shop had one of these and most did not even know these things exist.
.

What exactly were you asking the tranmission shops when you called them. I recently towed a heavy load cross country and need to replace (not flush) my fluid, but dont think I will have the time to do it myself in the near future. If I can find a shop with the right equipment, then I would have them do it, but I'm not positive what I am asking for. An exchanger that is powered by the transmission itself? Thanks for the input!
 
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Mabrodis

You are correct, I disconnected both lines as I was not sure which way it flowed. Its hard to trace the lines over the tranny. I did not shift through any gears while pumping the fluid.

Montana

This is a really, really simple procendure. 45 minutes tops. I would recomend doing the procedure yourself as I was not impressed with any shop I spoke with. If you still insist on going to a shop, I would ask around for one with a fluid exchange machine like Christo's. It uses no external pressure and only relies on the tranny pump to do the exchange. It is basically the same procedure that I have outlined above but the new fluid is sucked in through the second tube instead of added through the dipstick. If you have no luck finding a shop with one of these machines, (I called about 15 places and not one had one), at least find a shop that is familiar with the above procedure. I must emphasize again that you should do this yourself. By the time you call around and drive to and from the shop you will have been able to do this along with a oil, lube, filter.


I forgot to mention that I also removed the metal guard plate held on by four bolts directly behind the radiator. Cheers
 
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snowcruiser said:
I simply disconnected the bottom line going to the transmission cooler (near the radiator) and used two pieces of tubing to extend the this line and the male end of the tranny cooler itself. I put both of these tube ends in a clean five gallon bucket and started the engine with the transmission in park. Fluid then flowed quickly out of one of the tubes and into the bucket. As soon as it started to sputter and blow air I shut the engine off and refilled the transmission with approximately the same amount of fluid that was pumped into the bucket

Which tubing actually pump out ATF? Tubing to the cooler or tranny?
 
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The fluid came out of the tubing that ran to the cooler from the tranny, but aim both hoses at the bucket just in case.
 
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Shortly after I purchased my '94 I asked a friend that operates a repair shop to give me a flush quote. His normal price for a tranny flush for trucks and SUV's is $150. I asked about using full syn and he mentioned that if you replace the fluid every 50k there isn't really any reason for it.

Something to consider is that shops make their $$ on parts/supplies. That being said most are not open to customers bringing in their own fluid. Try a tranny overhaul shop, one that has old crusty wrenches working there. They are usually more open and more informative that the kids at Aamco.

cheers
Kris
 
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wingnutter said:
couldn't you have done this with your method? Once you figured out which was the drain hose, couldn't you have had the other suck up the new fluid?


Probably...but I went with the fill tube/dip stick to be sure.
 
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snowcruiser said:
Mabrodis

Montana

This is a really, really simple procendure. 45 minutes tops. I would recomend doing the procedure yourself as I was not impressed with any shop I spoke with. If you still insist on going to a shop, I would ask around for one with a fluid exchange machine like Christo's. It uses no external pressure and only relies on the tranny pump to do the exchange. It is basically the same procedure that I have outlined above but the new fluid is sucked in through the second tube instead of added through the dipstick. If you have no luck finding a shop with one of these machines, (I called about 15 places and not one had one), at least find a shop that is familiar with the above procedure. I must emphasize again that you should do this yourself. By the time you call around and drive to and from the shop you will have been able to do this along with a oil, lube, filter.


I forgot to mention that I also removed the metal guard plate held on by four bolts directly behind the radiator. Cheers

SnowCruiser - 45 minutes doesnt sound bad at all, I was initially thinking that it would be more involved then that. I'll have to crawl up under there and see if I can identify the tubes that need to be disconnected, and I am sure I can consult my FSM right? By the way, how did you dispose of the old fluid? There is sure alot of it.
 
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There have been many post on bobistheoilguy.com about using this method of draining. As someone suggested, you get a second five gallon pail and draw fresh fluid in throught the one hose while the other pumps it out. Just keep and eye to make sure that you don't run the pail dry of fail to pump new oil in (if it stops comming out the one hose you need to stop and figure out why.

Cary
 
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A picture indicating which tube draws the fluid and which discharges it would be very helpful ::):.

Thanks for the info. Sounds doable.
Rookie2
 

Photoman

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I had always thought the trans fluid was pumped through the cooler with no suction. The pump picks up fluid through the filter/screen in the pan.
FWIW, when I did mine I would just run the motor for maybe 10 seconds, then add more fluid. This way the pump was never run dry. From heavy equipment it was never a good idea to run a hydraulic pump dry (even for a short time) or to have the pump cavitate by having a low fluid level or running on a steep grade.

Bill
 
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ATF line removal

I have performed this exact replacement 5 months ago. The line that you need to remove is the upper rubber line comming off of the cooler, you need a pair of plyers to remove the OEM hose clamp off of the cooler, but you first remove the grill, phyllips screw driver to remove the front grill. You don't even half to crawl under the rig to ID the exact line, a longer 3/4 hose is needed to "extend" the upper hose to the 5 gallon bucket, it will be a loose fit but just keep it pointed twards the bucket and have your helper sit in the drivers seat and start and stop the vehicle on your command. I used the dipstick tube for the refill, I think that the fluid gets pushed thru the cooler as apposed to sucked thru. Use caution for the refill process, the vents for the trans are attached to the tube and could leak on the floor causing you to actually crawl under your rig for this. I just made sure that there wasn't 3 quarts in the funnel pushing down the tube, 1 at a time. If this doesn't make sense let me know, it is as easier than changing the engine oil.
 

e9999

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Does this trans-own-pump-push-out-old-fluid procedure result in minimal mixing of old and new fluid, or is each new quart simply mixed up with whatever is in there still?

Perhaps IOW, can you see a sharp change in color when it comes out at some point or is this very gradual?

thx
E
 
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Rainy Day FZJ said:
Use caution for the refill process, the vents for the trans are attached to the tube and could leak on the floor causing you to actually crawl under your rig for this.

This part confused me. Are you talking about the tranny and transfer case breather tubes that are attached to the tranny dipstick/fill tube? If so, why would fluid spill out of the breather tubes?

Thanks,
Rookie2
 
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It is a 2 part dipstick tube and if the middle seal is of questionable nature like mine was it will leak from that area a small amount. I could not tell if it was the breather tube connections or the o-ring it self.
 

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