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Discussion Starter #1
I talked to a guy at work who just changed his tranny fluid and he says its a total difference shifting, very smooth. The only reason i think i should change mine is that in the morning its really stiff and hard to engage, especially into 2nd from 1st, sounded like he had the same problem but in an 80's mustang( lol stangs). I've heard also that I shouldn't change my tranny fluid because the parts won't be used to having the new fluid but does that mean the factory oil stays in there forever? For example, I have black burnt oil, should I change it or does that mean the tranny is about dead anyways? Basicall, i need this tranny to last for as long as she can until that swap comes around.

If you guys think its a good idea to change the oil, what brands are recommended, I think a 75w 90 is best for my location.

Thanks guys.
 

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where do people come up with this crap?
Leave the oil cuz the tranny is already used to it??? WTF have you been smoking??
In that theory, you should leave the motor oil in there too, because the motor is used to it.
 

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kane2g, believe it or not, I have heard stuff like this before. Some people think parts get used to the oil which is in there already and a switch might cause leaks or even complete component failure. So, try to go easy on little240boy. ;)

little240boy, try using Red Line MT-90 or any other GL-4 rated gear oil like Specialty Formulation's MTL-P (75W-85) or MTL-R (75W-90).

http://www.specialtyformulations.com/index_files/Page457.htm

I just ordered MTL-P 75W-85 for my SpecV's 6-speed.

You'll almost surely see an improvement with new oil, even if it is only when the tranny is cold. Your tranny probably takes 2-3 quarts.
 

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Discussion Starter #4
So your positive about changing the fluid is ok? I just searched and found the info is all. The change seems easy enough except it seems kinda weird in the factory manual that they want you to put liquid gasket on the drain plug and the filler plug. Why is this? Should I be replacing the plugs while i change the fluid or only if its leaking?
 

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Discussion Starter #5
Also,whats the difference between the two reline products, the Mt-90 and MTL? The coldest it gets in Calgary Canada is probably -35 celcuis (-32 i think Farenheit) and probably +30 Celcius, 86 farenheit. What weightshould i be using, io was thinking 75w90 should be alright. What doyou think?
 

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Discussion Starter #6 (Edited)
Fluid Transmission Info

With all my pondering on what to do with my tranny oil, i came across this site. excellent info and hopefully helps you out.

http://www.gadgetonline.com/TransFlush.htm

Only real question I have is how to properly change the fluid on an 89 manual tranny. I think I should flush it but to be honest, i really have no idea how to flush or what it means to flush the tranny. Should I have it taken to a tech. and have them hook it up to the machine or will opening the drain plug actually clear out all/ 90% of the old fluid? Also, anyone got any advice to filling the tranny with new fluid or is it possible to get the angle on the fill hole to fill the tranny?
 

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To do this your going to need a 1/2" breaker bar to unscrew the drain plug on the trans. It is located on the underside of the trans facing the ground directly. Just unscrew that and drain all the gear oil. To refill the trans with the gear oil your going to need a short hose attached to the nub on the end of the gear oil bottle, and also I think its an 18mm wrench to unscrew the square tapered bolt... thing (technical term). This is usually pretty tough to unscrew so additional leverage may be required. Once you get the square tapered bolt thing bob off, go put your 3 quarts of gear oil bottles in some warm or hotter water. And let sit until the gear oil has warmed up. This will help the gear oil flow into the trans easier and save your fore arms a little bit. After this attache a 7" length of hose onto the end of the bottle and squeeze entire contents into the trans. You know you have enough in the trans after it is spilling in a steady stream onto the ground from the fill hole. I do this about once a week in different cars (240sx's)... but use mildly different tools. But this should be good enough for the average do it yourselfer...

if you do not feel comfortable with any of this take it to any sound mechanic and you should have your car back the same day depending on how busy they are
 

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Discussion Starter #8
Opium, so i shouldn't need to flush it, just drain and fill basically? And Redline MT-90 is ok or should i got with MTL?
 

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little240boy said:
Opium, so i shouldn't need to flush it, just drain and fill basically? And Redline MT-90 is ok or should i got with MTL?
I would suggest that if you have som extra cash to spend, buy enough to do it twice if you really want to flush out all or 95% + of the old Fluid.
Drain, Fill with new fluid, drive for like 30 min doing lots of shifting.
Put it in the Garage again, Drain the fluid, and then fill it up with more new Fluid.
I don't think this will affect the shifting any at all, it's only if you are really concerned about getting all the old fluid out!
 

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Bror Jace said:
little240boy, try using Red Line MT-90 or any other GL-4 rated gear oil like Specialty Formulation's MTL-P (75W-85) or MTL-R (75W-90)
good advice. also little240boy take dacheats advice.
 

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I'm not sure a "flush" is really necessary in this application ... but far be it for me to dissuade people going above and beyond the call of duty. ;)

But good synchro oils aren't cheap. They often run $8 or more per quart. So, I'd use just about ANY 75W-90 or 80W-90 gear oils for $3 per quart (in the summer) and then run that stuff for a week or so before draining it.

As for going thinner to deal with the extreme cold, if you are going with Red Line, you can mix the very light MTL with the heavier MT-90 in just about any ratio you want. Other than weight, they are chemically similar. A 50/50 mix is common to hear about on many car forums. I'm using an MT-90 heavy 80/20 mix right now in my SpecV's 6-speed and it's pretty good down to about -20F as long as I am gentle first thing in the morning.

Specialty Formulations has four GL-4 synchromesh fluids to choose from in different weights. In order of heaviest to lightest, here they are:

MTL-R (75W-90)
MTL-P (75W-85)
SynchroGlide
MTF Glide

I'd go with MTL-P ... but if you are really concerened about the cold, you might try Synchroglide. You can also e-mail the owner of the company (MolaKule from BITOG) or post an application question on his message board for a better match of fluid.
 

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Discussion Starter #12
Thanks Bror. What weight is the MT-90? I looked in the manual and it said for something minus 40 that 80w90 is good or 75w90. I think 75w90 should be alright, but i'll take your advice on the flushing thing.
 

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Red Line MT-90 is a 75W-90. MTL is a 70W-80.

Most "conventional" oils in this range are 80W-90 because they can't quite get the cold-flow characteristics of a synthetic.
 
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