Transmission Oil

AKimball92

AKimball92

True Classic
I am approaching the last of my engine build and will be starting the car soon. 1978 1300 with 4 speed trans. I know everyone recommends Redline MTL and many complain of transmission leaks. I am assuming that is because it is much less viscous than other oils.

How much Redline MTL should I order? I see on Amazon its 1 gallon for $67.55 or 1 quart for $19.74. I could not find it at the local Autozone or O'Reilly's

I have a feeling my boots might leak but its been 2 years since fluid was in the car to know. It did not leak prior to tear down. This winter I would like to redo my CV joints in the wheels (more research required) and possibly replace the boots. I have new seals for them already.
 
I purchased the gallon container. Had approx. 1/2 qt. left over.
I did not get any leaks fom using Redline. Shifting is much better. This was for my 5 speed trans though.
 
Hi Andrew,

The 74-78 Shop manual says the transmission takes 3 1/3 quarts. I ordered 4.
74-78 capacities.JPG
 
A fresh fill on a 4 speed takes more than 3 quarts but less than 4. Buy the gallon so you have extra if you need it.

I would replace the axle boots and clean the retaining rings and the mating surface on the case. Most 4 speed leaks are from where the boots meet the case and don't create a good seal.

Paper gaskets will at some point begin to weep slightly with most any oil. Perhaps slightly more with synthetic but you really shouldn't have more leaks with synthetic. If it had GL1 in it and was leaking, it will likely leak slightly more with the lighter weight MTL.

You really don't want to use anything other than MTL.
 
Dallarax19 said:
Try these guys. I saw they carried it the other day. Pontiac store had only 1 qt left so try waterford
http://www.mazzaautopartswaterford.com/

Or here;
https://www.summitracing.com/parts/red-50205
I usually get stuff the next day
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Oil ordered from amazon. It was cheaper than Summit and prime shipping.

If you are ever out and about in the Dallara and in the southern SCS neighborhood please stop by. I would love to see you X1/9! I also have you manual I believe.
 
Steve Hoelscher said:
A fresh fill on a 4 speed takes more than 3 quarts but less than 4. Buy the gallon so you have extra if you need it.

I would replace the axle boots and clean the retaining rings and the mating surface on the case. Most 4 speed leaks are from where the boots meet the case and don't create a good seal.
Click to expand...

I will back my boots off and look over that seal surface again. The brackets were freshly cleaned and painted but should have paid more attention to the boots themselves.

Steve Hoelscher said:
You really don't want to use anything other than MTL.
Click to expand...

That quote from Steve H. should be bookmarked and in the best of knowing your experience with these cars.
 
Yeah keep both of those links fresh. Amazon or Ebay are always a go to for sure but shipping time is hit or miss. If you need something quickly and is an oddity, Mazza and Summit are a good solution, it is a trade off of a few extra bucks for speed. I got oil for my RS in 3 days off of Amazon but I had some other small bit that took a week to get. I didn't need the oil that quickly but I needed the part as quickly as I could get it. I was dragging my feet on which oil I was going to use in the Fiat this build and when I figured it out I bought it locally because I needed to move over center and onward. I probably over spent about $12 but it was done and off the to do list.
 
I got MTL at my local Knecht's auto parts for 14.95/qt, seemed expensive at the time, feeling better about it (shifting, too).:D
 
Jefco said:
I got MTL at my local Knecht's auto parts for 14.95/qt, seemed expensive at the time, feeling better about it (shifting, too).:D
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Wow, MTL cost has really increased since I was doing X resto/resurrections. Was $8/qt then! Bought it by the case since SOP was always to change all fluids. One exception was a tranny that came to me as sweetest shifting I'd ever had. Figured it already had MTL. Eventually I dumped the fluid & was surprised it was gooey GL whatever. MTL made a great tranny even better. I'd say it's still a bargain at twice the price.
 
Well, I am happy that everyone has such a wonderful experience with MTL. I ran it for the last many years and finally just got fed up with the leaks at the case halves. It would leave a running puddle after each shut down. People would come into my office and say "You car is leaking something!" it was that obvious. Anything I put down in the garage to absorb the leaks was saturated pronto. This was a recent rebuild from one of our vendors. Obviously not sealed well enough. Shifted nicely, not enough to keep the 2nd synchro from dying. I put GL-1 back in. Smaller leaks now. Shifts awful. But since 2nd gear, one of the most used shifts, is a problem, I hardly notice the difference in shifts overall.
 
Larry, sorry about the trouble you are having. Sadly, I see this kind of thing often. Close to half the transmission builds I get I am going in behind somebody else and sorting out the mess they made of it. Your experience is not unusual, However, leaks and poor shift quality are not a given and certainly aren't the result of using MTL (or other synthetic). GL1 might leak less than MTL but certainly isn't a solution.
 
LarryC said:
Well, I am happy that everyone has such a wonderful experience with MTL. I ran it for the last many years and finally just got fed up with the leaks at the case halves. It would leave a running puddle after each shut down. People would come into my office and say "You car is leaking something!" it was that obvious. Anything I put down in the garage to absorb the leaks was saturated pronto. This was a recent rebuild from one of our vendors. Obviously not sealed well enough. Shifted nicely, not enough to keep the 2nd synchro from dying. I put GL-1 back in. Smaller leaks now. Shifts awful. But since 2nd gear, one of the most used shifts, is a problem, I hardly notice the difference in shifts overall.
Click to expand...

As I heard the history of it, mineral oils (PAOs) swell seals somewhat. Engineers knew this and accounted for it in tolerancing parts. When synthetics first came out, they didn't swell seals like the PAOs did and did not seal as well. Eventually, the chemical engineers figured to add in chemicals to the synthetics to mimic the PAOs tendency to swell seals and that problem has largely gone away, but the reputation persists.
Redline is thinner than most garden variety GL-1 (75W-80 vs. straight 90) so the reduction in leaking may be just due to the viscosity increase. Just a shot in the dark but there is a screw that is a wet cavity at the bottom of the transmission. It intersects the shifter shaft. It is for one of the trans mount screws so the vendor would not have had an opportunity to seal it. Maybe that is where the leak is really coming from? Marked with a green dot below. Maybe try sealing the threads of that screw?

IMG_20180609_111757078_HDR[1].jpg
 
Possible the leak is due to the M8 stud used on the lower mount that is not sealed? Gear box oil can leak from that stud if not sealed during installation.

Bernice
 
That stud goes in a blind hole that is not supposed to be machined through to the shift rod bore. Unfortunately, many people replace the stud with a bolt of the same length as the bolts used in the rear positions and break through the bottom of the hole into the shift rod bore, causing the leak. Removing the stud, place a plug of Black RTV and then applying black RTV to the stud threads should seal it up.

To make the seal work you will want to flush the hole with brake clean and blow it dry with compressed air first.
 
Mine still has the stud in that location. I will need to give that stud a look in my next maintenance session in which I will replace the lower mount yet again.
 
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