M22 fluid leaks and checking

[babaron]

Can anyone tell me how I can check the transmission fluid level on my '69 L 78.  It's an M22 and I notice small leaks of light brown fluid from several areas of the housing after driving.  Is this normal? Thanks!

[1968RSZ28]

Can anyone tell me how I can check the transmission fluid level on my '69 L 78.  It's an M22 and I notice small leaks of light brown fluid from several areas of the housing after driving.  Is this normal? Thanks!

Remove the transmission fill hole plug.  The transmission fluid level is correct when the fluid level is at the bottom of the fill hole.  No, the transmission shouldn't leak.

Paul 

[Kelley W King]

According to Danny Nelson ( the 4 speed guy at most large shows) there are two main causes for leaks. 1st is overfilling, if the trans is not level such as raiseing the front or rear only or filling while out of the car it will leak. He even told me to do a 1/2 inch below the hole. The 2nd is the cluster gear shaft at the front of the case where it touches the bell housing. 4speedman.com machines a groove on the shaft for an O ring in his rebuilds. He told me a trick about this one that worked on my Z car. Loosen the trans bolts about 3/8 inch and slide the unit back. Nothing else has to be loosened. Now you can see the shaft. Put some good sealer on a business card and carefully slide it in over the shaft hole. Tighten the trans bolts and ride. I tryed it and it works. I even do it when replacing a trans whether I know it leaks or not.

[babaron]

Thanks, guys.  I put my finger in as far as it will go and didn't feel any fluid level.  It looks like I'll need to add some.  Any suggestions for any specific brands or grades of fluid?

[JohnZ]

Any suggestions for any specific brands or grades of fluid?

Any brand-name 75W90 or 80W90 gear lube will work fine - that's what it was designed, developed, and tested with; you don't need any exotic lube.

[babaron]

Just ordered 2 quarts of Redline MT 90 75W90 GL-4 fluid.  Hope that was the right stuff. I'm going to drain what's left of the old stuff out 1st. Thanks guys!

[copo69]

John,  I've always used GL-4 rated 80/90 lube as I understood the newer GL-5 rated lubes now more commonly sold would damage the synchros over time.  What's your opinion on this?

[JohnZ]

John,  I've always used GL-4 rated 80/90 lube as I understood the newer GL-5 rated lubes now more commonly sold would damage the synchros over time.  What's your opinion on this?

I think the "stories" about GL-5 lubes damaging the brass synchro rings are just that - "stories"; has never had any effect on any of the T-10's and Muncies I've had over the last 40 years.

[babaron]

John, the stuff I ordered, Red Line MT-90SAE 75W90 API GL-4 Gear Oil, is synthetic.  I haven't poured it in yet.  Some say don't use synthetics, others say it's fine.  What's your opinion?  If you do not recommend it, then what would you recommend and where can I get it?  Thanks!

[babaron]

If anyone else has an opinion, please weigh in. Thanks!

[Gramps69Z]

 

 
 As John stated, any brand-name 75W90 or 80W90 gear lube will work fine - that's what it was designed, developed, and tested with; you don't need any exotic lube. 

 You can buy gear lube at most retailers and parts stores.  Back in the 70's we used straight 90w in our rear ends and transmissions.
 

[babaron]

So by "any...gear lube", I should take that to mean synthetic is OK?

[Stingr69]

I do not like the synthetic gear lube. I did a drain and fill with synthetic gear lube and it leaked out the rear seal. The tranny noise was more noticeable as well and not in a good way.

I replaced the synthetic with GL-4 conventional gear lube and replaced the rear seal. The sound went back to normal and the leaks are no longer an issue. Your results may vary - Please post if they do.

We could allways use another good lubricant experience thread.

-Mark.

[babaron]

Thanks, Mark. I decided not to use the Redline.  I just ordered Stalube API GL4 85W90 and am waiting for it to come in.  I'll let  you all know how it works out.

Ron

[sixt9x33rs]

You dont have to order anything just go to a parts store and buy the right weight that is on the shelf.