Transmission Fluid

[armerdan]

Hi all. I just last week got my 92 MTX SHO back from the transmission shop, and when I first got it back I noticed it was really hard to get in gear (esp from dead stop). So I took it back to the guy and he said to drive it for a while, something about how it takes some time to circulate the oil???? I thought that was , but he was closing the shop up for the weekend so I said what the **** I'll drive it for the weekend and bring it back Monday. I took it up on the highway and drove it a couple hundred miles over the weekend, (went to see my grandmother). and by the time I got back, it was shifting GREAT. So all this week I've been driving it every day, and really loving the fact that it's running good (finally). The day before yesterday (Thursday) I did not drive it at all and yesterday (Friday) I went to drive it and it was shifting hard again for a couple of (2) miles then it got good again, I thought that was really weird so I called the transmission guy to ask what kind of fluid he put in it thinking maybe he put the wrong stuff in He tells me that he (get this) "mixed ATF and 90 weight gear oil" !@#* I have NEVER head of ANYONE doing that before! So (at last) here are my questions.

1) Have any of you ever heard of mixing 90 weight and ATF?

and
2) Is it possible that when the two weren't mixed yet it was shifting like crap, and when the two mixed it thinned out the 90 weight so it shifted better

and
3) when I let the car sit without driving it (Thursday) the 90 weight gear oil and the ATF separated again, causing it to shift like crap until they mixed again?

and
4) How screwed am I???

Thanks in advance for the help.

 

[Black Stallion]

Drain it and put some Mobil 1 ATF in it. (Or whatever you like). I think that it takes time to circulate, I mean it only takes like 2 miles like you said. I think all MTX's are like this especially when it is cold out.

 

[Bizzy]

#1 - Get the gear oil out pronto.

#2 - It does take time to get the fluid to fully coat the internals. Back in the day I used a 50/50 blend of regular ATF and Hot Shift which was suggested at that time "as a good mixture" by Shawn at IPT. It was garbage needless to say and shifting got harder and harder each day that went by. So I drilled a drain plug in my trans and refilled it with Mobil 1 synthetic. At first I didn't notice a huge difference but within 50 miles it was much improved. After 100 miles it was 100% better.

IMO, changing the fluid out should be your first priority. After that, if it doesn't improve within 50-100 miles then take it back to him.

 

[wood_e]

Yeah gear oil is a no-no in SHO transmissions. Now gear oil is spec'd for my Audi, but I'm going to put in GM synchromesh pretty soon...

Mixing is quite common in transmissions spec'd for gear oil for cold weather.

 

[armerdan]

Do you guys know about how much fluid it will take to fill her up? I do plan to use mobile 1 synthetic ATF, based on some things I have been reading it looks like good stuff.
If I were to try to change the fluid myself, do I need to drill a drain in the transmission? I would REALLY rather not. I have heard of people sucking it out through the fill hole. What do you experts recommend as the best way to get the old stuff out? I assume I should get all, or as much as possible out. Or should I just take it back to this guy and tell him to change it out since it was his fault to begin with?
I know I'm a ******** to take it to a local instead of a SHO expert:banghd:

 

[armerdan]

I really appreciate the help

 

[armerdan]

Ah yes I see many places telling how to drain an MTX SHO

 

[Bizzy]

Do you guys know about how much fluid it will take to fill her up? I do plan to use mobile 1 synthetic ATF, based on some things I have been reading it looks like good stuff.
If I were to try to change the fluid myself, do I need to drill a drain in the transmission? I would REALLY rather not. I have heard of people sucking it out through the fill hole. What do you experts recommend as the best way to get the old stuff out? I assume I should get all, or as much as possible out. Or should I just take it back to this guy and tell him to change it out since it was his fault to begin with?
I know I'm a ******** to take it to a local instead of a SHO expert:banghd:

3.1 quarts is the capacity but if you suck it out 3 quarts should do fine because you'll never get it all out. There is a bolt that you can remove that will allow the trans to drain but I'm hesitant because if you move anything while this bolt is out it can cause a lot of problems.

 

[armerdan]

As long as I don't touch the gear selector while it's out I should be fine though right? I was kinda thinking I would suck it out anyway, unless I would be able to get more of it out through this bolt hole?

 

[warmonger]

i like my method..i use a rubber hose,shop vac and duct tape

 

[armerdan]

Ok Sounds good.

 

[armerdan]

Well I sucked out about 3 quarts of tranny fluid and boy did it stink of 90 weight gear oil So I filled it up with some Mobile1 synthetic ATF and it shifted much better right away, and after 30 miles even better, so I guess I'll see how it is in about a hundred miles or so. thank you all for the help and support.

 

[platoribs]

Drilling, tapping, and installing a drain plug is really easy.

 

[Bizzy]

Drilling, tapping, and installing a drain plug is really easy.

Easy yes....but not for the faint of heart. The plug hole absolutely MUST drill straight in and tapped properly. Otherwise you're going to have a crooked hole that won't hold an ounce of trans fluid in. If you've never done one it's best to get a practice run in on a scrap case.

 

[armerdan]

Thank you Beth, my thoughts exactly and since I did not have a scrap case I sucked the fluid out with a shop vac, a 1 gallon tuperware container, and about 3 feet of 5/16's vacuum line. I was amazed that it really only took about 10-15 minutes to suck out the fluid once I got my shop vac rigged up. Anyway shifting even better now after about 75-100 miles.:hdance:

 

[warmonger]

ahhhh so you used my method!!! shop vacs are great,i've use them to drain my coolant system too

 

[armerdan]

ahhhh so you used my method!!! shop vacs are great,i've use them to drain my coolant system too

You know...... That is a really good idea
I just used the drain plug that is designed into the radiator and attached a few feet of 3/8's fuel line to the "outlet port kinda thing" so I could send it straight to my catch can and it didn't go everywhere.

But I bet you could get the same amount of antifreeze out if you used the Vac method, and you wouldn't have to climb under the car **** I had to jack mine up to fit the catch can under it.

 

[jedhead]

When I installed my drain plug, I had to drill slowly to prevent galling since the casting for the case seems porus. I also installed a plug within a plug so the one in the case remains.


Bob

 

[AREA 91]

When I installed my drain plug, I had to drill slowly to prevent galling since the casting for the case seems porus. I also installed a plug within a plug so the one in the case remains.


Bob

Darn it Bob, why didn't I think of that! Oh well, age before beauty.

 

[jedhead]

I also wanted to use brass since brass is softer than aluminum. I practiced on my old transmission case a couple times first.

Bob