PCM Transmissions

So last season I changed the fluid in my PCM 1.23:1 trans from the 20w that was in it to Mercon/Dexron which is what was recommended by the guys at skidim.com and at the beginning of this season my trans started going out. Maybe it was something else that caused it maybe not I dunno but I'm getting ready to install the reman trans that I bought and I have no idea what I should put in it

just curious but how many hours on the boat? ive read that in the 2001s that have the velvet drive 1 to 1s (pcm engine) that they need rebuilt around 800 hours. mine made it to 940

I have just under 800 hrs on mine it's a 91 Supra

how did it start going. i actually just rebuilt mine. slipping in forward?

Yup that's exactly how it started

The newer pcm transmissions use transmission fluid. I'm not sure what the older ones used. Transmission fluid has almost no lubrication properties compared to oil. If it needs oil for lubrication and you put transmission fluid in that is likely the cause of the failure. I would go to the PCM website and contact them for info on the older model. They have owners manuals availabe for download starting in 2000. The website is www.pleasurecraft.com

umm, huh. transmission fluid has no lubrication properties. have you every seen transmission fluid. Transmission fluid is actually more lubrication and more viscous. the pcm repair manual calls for the (upgrade) to transmission fluid. it is basically oil but actually a more refined version of it than motor oil. you would know that it is lubrication if you ever spilled it on the floor and tried to mop it up. I am using mobil atf. it can use dextron, 200, 220, or just regulr mobil atf. This is from first hand experience, the slipping in forward is either the clutch plates or a leak in the pressure journals. check the allignment of the engine to the shaft. if it is off by even the slightest amount, it can cause a stress crack to develop in the clutch drum. if it is also in reverse, then it is most likely the oil pump.

Take it from me, i had the the tranny apart 3 times over the last month figuring this out.

check your oil pump on your transmission. it can cause this problem if its going out. i still have this problem occasionally so this winter mine is getting a new oil pump. most likely you need your clutch packs replaced. its very common for that many ours

Ryan, sure transmission fluid has some lubrication properties but it is primarly a hydraulic fluid, try putting it in your engine and watch it fail from lack of lubrication. Put oil in your transmission and it will slip and burn out the clutch plates. Transmission fluid and engine oil have different purposes and properties.

hmmm Well either way I have a Re-Man tranny sitting in my garage waiting to be installed so . . . . . I'm kinda confused now

i got the same advice from skidim, changed mine from 20 wt to dexron/mercon years ago. have since replaced the dex every other year. notice no difference, problems or issues after 100+ hours. My local dealer, PCM, and skidim recc. the dex/merc. Probably just a fluke yours went south after the change.

Darrel, that's the response I'm looking for I was thinking the same thing . . . thanks

Montgomery, did you call Eric at FFMARINE???

george, just thoguht you may like to read this.
http://en.wikipedia.org/wiki/Automatic_transmission_fluid

It is "optimized" for use in gear lub applications. will it lubricate an engine, yes. the question is, why would you spend 5 bucks a quart to lubricate your engine. it is an "oil". oils lubricate. in this case, atf is an even more highly refined and slippery oil. also, to rebut your assertion that if you put oil in a transmission it will burn out your clutch plates, why did the early pcm transmissions come with 20w. they certainly weren't exploding clutch plates as soon as they came out of the factory. in fact, many old automotive transmissions used just heavier weight oil in them. so, the bottom line is, they are both oils. if you put transmission fluid in your engine, it will not blow up. it is thicker and more expensive so you will no doubt lose power and pay more but it won't blow up. premature oil pump failure from having to work harder but it will act exactly the same. can you put oil in a transmission, yes. will it be able to hold pressure as well, no. but it has been used. The problem i had george was you told this poor gentleman that he blew up his transmission by using a fluid that is "recommended by pcm engineers" for use in their transmissions. It's detrimental to spread false information. in this case, he may have never found the true cause of his tranny problems if he had listened to you.

also, transmission fluid is used in gear boxes in differentials. this is acting as "gear lube". hmm, i wonder what is inside transmissions.

Ryan, this is my last post, I never said he blew his transmission. I said I had no idea what to use in his boat but that oil and transmission fluid have different purposes and should not be interchanged. I spent a year developing a lubrication plan for a large automotive foundry several years ago working with lubrication engineers from Texaco and Shell. I can't find a really technical explanation of the difference to post here. Here is an non-technical explanation from a auto repair web-site.

Transmission fluid is a hydraulic fluid and motor oil is a lubricant. While transmission fluid does have some lubricating properties, it is not enough to sustain an engine. Motor oil is an excellent lubricant, but not such a good hydraulic fluid so it can not be used in a transmission.

Transmission fluid can also be used in power steering systems without harm since that is a hydraulic system, but not motor oil. Never, ever under any circumstances should transmission fluid or motor oil be used in the brake system. It would result in brake failure and do considerable damage to the brake components.

http://autorepair.about.com/library/a/1/bl126.htm

"The newer pcm transmissions use transmission fluid. I'm not sure what the older ones used. Transmission fluid has almost no lubrication properties compared to oil. If it needs oil for lubrication and you put transmission fluid in that is likely the cause of the failure."

That sounds to me like you told him that the likely cause of his failure was using atf. And also, on using motor oil in a transmission, sorry man, pcm did that. mine came with 20w and it worked fine. and as many people have said including me, it works just fine with atf. so yes, the pcm(hydraulic transmission) will run with 20w motor oil and run well. Also to your point of not using tranny fluid in an engine, have you ever tried it. i have. using an old engine, in an old car i decided to test it. guess what, it didn't blow up. i even tried to run it hard. is it a fluke, that an engine is able to run on it? my guess since engines aren't exactly rocket science is no. my point is that yes, it may be more beneficial to use a better designed oil for the application but it will not cause immediate failures like you suggested with your posts.