X19 transmission fill plug location

L

lakeradio

New Member
Hello, New to forum.
Have 1979 x 1/9. The transmission fill plug/bolt is not near the
Reverse switch. Someone in forum reported for cars that the fill
Plug is not near Reverse plug, then it is on right side of transmission.
On my car there is a bold head about 2 inch rear of speedometer
Cable above right wheel output shift.
Is this the fill plug for my car?
Was thinking about filling with Lucas Heavy Duty SAE 80w-90 gear oil.
Would this be OK??
THANKS
lakeradio
 
lakeradio said:
Hello, New to forum.
Have 1979 x 1/9. The transmission fill plug/bolt is not near the
Reverse switch. Someone in forum reported for cars that the fill
Plug is not near Reverse plug, then it is on right side of transmission.
On my car there is a bold head about 2 inch rear of speedometer
Cable above right wheel output shift.
Is this the fill plug for my car?
Was thinking about filling with Lucas Heavy Duty SAE 80w-90 gear oil.
Would this be OK??
THANKS
lakeradio
Click to expand...
That would be an Absolute NO on that "Lucas Heavy Duty SAE 80w-90 gear oil".. Risk of wrecking the syncos, poor shifting and more is very real. Use the well proven Redline MTL..

The fill/drain plugs on the transaxle are tapered thread, this means using teflon sealing tape on the threaded plugs and Do Not Over Torque the plugs upon installation. Excessive torque will crack the filler/drain threaded boss in the transaxle housing.. Causing an enormous amount of grief that is not appreciated during installation of these plugs.

Bernice
 
Once you locate the plugs, I'd suggest a complete fluid change rather than just topping it off (not sure, but if that's what you had in mind).
 
I thank everyone for fast help. I have had oil leak problems when changing
to synthetic oil. I read a government report on Mobil one engine oil. Testing
showed Mobil one was superior to non synthetic oils. I purchased a new
TOYOTA in 1979. The first oil change I used Mobil one. Soon after I was
At a Toyota dealership have rear engine seal replaced do to leaking.
I now have 5 cars newer than 1995 and use full synthetic in them.
I am not new to Fiat automobiles having had three 1979 X 1/9`s, a 3P and
a 124 Spider Turbo.
So, after all the response to my first posting I called Midwest-Bayless.
I was told never use synthetic oil in my X 1/9. I would have oil leaks.
For transmission I should use GL-5 transmission oil. I purchased
1 gal Valveline GL-5 from Autozone and change transmission oil.
I am sure some have used synthetic in transmission without oil
leaks. I did not want to take the chance. The cost to remove and
repair leaking transmission must be thousands.
Thanks again
Lakeradio
 
You don’t want to use any oil which is EP Extreme Pressure as the additives will attack the synchromesh components in the transmission.

Most GL5 oils are EP and should not be used.

Oil for the gearbox Fiat X1/9

Hello. I recently repaired the gearbox Fiat X1/9. In the manual it is written Oil for the gearbox GL-1 not ep. But they do not produce it. I met on the forum that you can pour GL-4. Will it hurt the box or not? Thank you
xwebforums.com
 
lakeradio said:
For transmission I should use GL-5 transmission oil. I purchased
1 gal Valveline GL-5 from Autozone and change transmission oil.
Click to expand...
If you use a GL-5 you must be careful that it is specifically recommended for use with soft metal synchros - most are not.

The "can't go wrong" consensus choice is Redline MTL.
 
lakeradio said:
I thank everyone for fast help. I have had oil leak problems when changing
to synthetic oil. I read a government report on Mobil one engine oil. Testing
showed Mobil one was superior to non synthetic oils. I purchased a new
TOYOTA in 1979. The first oil change I used Mobil one. Soon after I was
At a Toyota dealership have rear engine seal replaced do to leaking.
I now have 5 cars newer than 1995 and use full synthetic in them.
I am not new to Fiat automobiles having had three 1979 X 1/9`s, a 3P and
a 124 Spider Turbo.
So, after all the response to my first posting I called Midwest-Bayless.
I was told never use synthetic oil in my X 1/9. I would have oil leaks.
For transmission I should use GL-5 transmission oil. I purchased
1 gal Valveline GL-5 from Autozone and change transmission oil.
I am sure some have used synthetic in transmission without oil
leaks. I did not want to take the chance. The cost to remove and
repair leaking transmission must be thousands.
Thanks again
Lakeradio
Click to expand...

Valvoline's website specifies their GL-5 gear oils as EP type. I strongly recommend against using any EP type gear oil. It will attack the coatings on the synchronizers and cause them to fail.

As noted in the thread linked above I recommend only Redline MTL or MT90 for the X1/9 transaxle.

I understand your apprehension at using synthetics, everybody hates leaks. My experience with synthetics has been very good. I have used Mobil 1 in many of my vehicles for many, many years without issue, including my X1/9s. Nor has MTL caused issues with leaks in my transmissions. I am surprised to learn that MWB doesn't recommend synthetics.

If you do not want to use a synthetic gear oil I would suggest simply using a 20W50 petrolium motor oil in the transmission. It will work better than GL1 or any EP gear oil.
 
Last edited:
lakeradio said:
I thank everyone for fast help. I have had oil leak problems when changing
to synthetic oil. I read a government report on Mobil one engine oil. Testing
showed Mobil one was superior to non synthetic oils. I purchased a new
TOYOTA in 1979. The first oil change I used Mobil one. Soon after I was
At a Toyota dealership have rear engine seal replaced do to leaking.
I now have 5 cars newer than 1995 and use full synthetic in them.
I am not new to Fiat automobiles having had three 1979 X 1/9`s, a 3P and
a 124 Spider Turbo.
So, after all the response to my first posting I called Midwest-Bayless.
I was told never use synthetic oil in my X 1/9. I would have oil leaks.
For transmission I should use GL-5 transmission oil. I purchased
1 gal Valveline GL-5 from Autozone and change transmission oil.
I am sure some have used synthetic in transmission without oil
leaks. I did not want to take the chance. The cost to remove and
repair leaking transmission must be thousands.
Thanks again
Lakeradio
Click to expand...
Would be surprising if Midwest-Bayless would recommend using GL-5 gear oil in the x1/9 transaxle. Using GL-5 in the transaxle is one of the most rapid ways of destroying the Porsche syncos in the x1/9 transaxle. Porsche syncros use a coated friction band to synchronize or match rotating speed between two different gears (Porsche syncros are already slow to synchronize as they are by design). GL-5 has EP (Extreme Pressure) additives which is specifically designed and intended to prevent hypoid and similar gears from welding together due to the high pressures on the helical spiral gear teeth faces. That anti-welding additive significantly reduces the ability for the synchro friction band to producing friction. This significant slows down the synchronization action and demands more force on the Porsche synchros to work... at all. See the innards of the x1/9, 5 speed transaxle in Xweb link previously posted.

5 Speed Transaxle, Part Three Gear Sets.

The input gear set and Pinion gear set from a 1979 transaxle. The reverse gear on the input gear set. This often gets chipped, worn and abused as previous owners and abuser crash the shifter into reverse gear. If this gear is excessively chipped or damaged, the entire input gear set will need...
xwebforums.com

So, if you're wanting to destroy the Porsche syncros in your x1/9 transaxle by filling it with any GL-5 gear oil.. proceed with said "recommendation".

Oh, know good quality parts for the x1/9 transaxle is now pricy and no so easy to get... Plenty of aftermarket "junk" parts that "fit" but do not function properly... at all or last for a short drive.. Word to the wise would be to do all possible to preserve the OEM fiat transaxle parts much as possible by using the very best proven oil for the transaxle.. one of which is Redline MTL..

As for synthetic oils (any current) causing oil leaks, that is another moto myth that should have died decades ago. Prime cause of oil leaks is dead and dying oil seals. Lot has changed with lubricant technology since 1979.. What once was in 1979 is no longer what is available for purchase today. Well over a decade ago, purchased a rebuilt over drive transmission for the 1957 Triumph TR3. The rebuilder was absolutely insistent on using vintage Dino juice non-detergent W30 engine oil.. or the transmission will leak... This rebuilt over drive transmission was filled with Redline MTL (synthetic oil) from day one.. to this day, oil leaks have been.. nil. And synthetic oil is used in all the cars here from Triumphs to Miata to Saab to ...oil leaks not an issue..

So, if oil is leaking, replace those dead-dying oil seals.... ALL of them. They do not and never will last forever or have a "best by" date ala "mileage".


Bernice
 
Steve Hoelscher said:
Valvoline's website specifies their GL-5 gear oils as EP type. I strongly recommend against using any EP type gear oil. It will attack the coatings on the synchronizers and cause them to fail.

As noted in the thread linked above I recommend only Redline MTL or MT90 for the X1/9 transaxle.

I understand your apprehension at using synthetics, everybody hates leaks. My experience with synthetics has been very good. I have used Mobil 1 in many of my vehicles for many, many years without issue, including my X1/9s. Nor has MTL caused issues with leaks in my transmissions. I am surprised to learn that MWB doesn't recommend synthetics.

If you do not want to use a synthetic gear oil I would suggest simply using a 20W50 petrolium motor oil in the transmission. It will work better than GL1 or any EP gear oil.
Click to expand...
My first transmission oil change (1990's) I used regular motor oil. No issues. Once I finally addressed the eventual leaks (shift shaft seal & RH axle seal) I filled with Redline MTL. Shifting was notably better, but I did do the failing lollypop at the same time. No leaks a year later.
 
Correction, after all the comments about GL-5 I too was sure Midwest-Bayless
Would not recommend it. So I contacted then again and they recommend
GL-1. Communication problem. I Drained the GL-5 and filled transmission
With NAPA GL-1.
 
lakeradio said:
I Drained the GL-5 and filled transmission
With NAPA GL-1.
Click to expand...
That will work, it's what was what was originally specified for these cars and getting the wrong GL5 out of there is absolutely the right thing to do. But be aware that oil technology has improved a lot since these transmissions were designed a half-century ago, and Fiat's engineers probably would have specified a suitable modern synthetic instead of coagulated dinosaur blood if they had that option back then.

No reason to switch out the GL1, but the next time you change the stuff there's a lot to be said for springing for the Redline MTL or equivalent.
 
I still use GL-1 in my 84 since new and still shifts like butter.
Colder fall weather I’d switch over with the MTL in one of my 87s but not much cold weather lately for any of us.

IMG_4300.gif
 
lakeradio said:
Hello, New to forum.
Have 1979 x 1/9. The transmission fill plug/bolt is not near the
Reverse switch. Someone in forum reported for cars that the fill
Plug is not near Reverse plug, then it is on right side of transmission.
On my car there is a bold head about 2 inch rear of speedometer
Cable above right wheel output shift.
Is this the fill plug for my car?
Was thinking about filling with Lucas Heavy Duty SAE 80w-90 gear oil.
Would this be OK??
THANKS
lakeradio
Click to expand...
I'm using Amsoil ZRod 10W40 in my 1987 X1/9 in Southern California. It's high Zinc content will keep your Cam Lobes and Lifters happy. Works great, and no worries.
Never, Never use EP (Extreme Pressure) Gear Oil in your Transaxle! After a lot of search and study, I've settled on Redline MTL 75W90 Non-EP. It satisfies the requirements of the recommended 80W90 Non-EP Gear Oil. You will make your own decisions of course, but these recommendations will save you from a lot of grief and heartache, and keep your baby right. There are people on this forum who know much more than I do, but the lubes I listed will definitely work in your ride without messing up your expensive drive train.

Best wishes, and have fun with your X!
 
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