Transmission Oil Change - Worked like a charm

[BigDaddyJoe]

Purchased my 1976 Fiat Spider 1800 about 2 weeks ago and am in the process of buying tools and maintaining this beauty. I wanted to take a moment and say thank you to the contributors to this forum. It was because of your thoughts, methods, and research that my Transmission Oil Change went off without a hitch. In an effort to pay it forward to future readers, I'll highlight my experience:

64k Original Miles

Shifting was pretty good with the exception of getting into 1st gear from a stop (I would have to shift from 2nd to 1st to make it stick), Reverse would sometimes take a try or two, 5th wasn't a very smooth transition, & I would get an occasional whine in 3rd and 4th while driving.

Process:
Purchased Napa SAE 90 GL-1 Oil (Only available in a 5 gallon bucket in my area for $70, but figured it's what Midwest 124 uses, so it's good enough for me).*** On a side note, if you are in Boise, stop by and you may have some, Ha. I have GL-1 for days now.
Purchased a clear plastic tube 1/4 inch (would so 1/2 or may 3/4 inch after taking close to 4 hrs to fill transmission). Hooked plastic tube to an empty gallon water bottle with rubber gaskets on the inside and outside of the drilled water bottle (hot glued gaskets to mitigate leaks).
Jacked up all 4 sides (utilized a 2x4 with cut in the middle for the rear diff plug on the "pumpkin") Idea was to keep the car level for draining and allow the maximum new oil to be installed.
Opened up the Oil Intake for the Transmission - 11/16's wrench is what fit
Opened Transmission Drain Plug - Fiat allen wrench in tool kit
Drained Transmission Oil - waited about 20 mins
Wiped off drain plug (metal was noted on the interior magnet plug) & threads of plug and Transmission.
Reinstalled plug using the tool kit allen wrench
Ran tube from fabricated water bottle (located on a step stool with center hole outside the passenger side of the engine compartment - elevated).
Measured out about 2 qts (had leftover when oil was leaking through fill hole)
Removed line, water bottle, and re-installed fill plug.

Driving
Put about 10 miles on a cold engine after Transmission Oil Change.
Shifts like a dream. I really wasn't expecting such a drastic difference. Finding 1st from a stop is no longer an issue, no whining what so ever, transitions are ridiculously smooth now. My expectations are definitely exceeded by this process. I was thinking maybe a 20-30% improvement and planning on a transmission rebuild, but if this result is the new expectation, that repair will not be needed in the near future.

Again, thank you contributors for your time and expertise. This is my 40th birthday project and I've never attempted automotive mechanics, but desired a new hobby & after driving a 1964 Fiat 500 Giannini in Italy, I was hooked. Looking forward to future posts, comments, and updates on these beautiful machines.

[18Fiatsandcounting]

Shifting was pretty good with the exception of getting into 1st gear from a stop (I would have to shift from 2nd to 1st to make it stick), Reverse would sometimes take a try or two, 5th wasn't a very smooth transition, & I would get an occasional whine in 3rd and 4th while driving.

Gulp, I thought this was normal for a Fiat transmission. Perhaps it's time to change my oil....

Seriously, though, glad you were able to get it straightened out.

-Bryan

[redcars]

I'm glad your oil change when so good. The next time you change the transmission oil also remove the rear drain plug. This pnug drains the real compartment which will not drain through the main drain plug. It will fill with the normal fill plug,but not drain. It doesn't hold much oil so no big deal . For now I would just wait until it needs another oil change. Enjoy your ride.

[kilrwail]

Good for you, using that technique. I use 1/2" clear plastic tubing and a small funnel - it's a very quick fill.

[BigDaddyJoe]

Thanks for the comments gents. Next up, rear diff flush and full clean out (new gasket, happy clean interior). Looking forward to it. Garage therapy is a wonderful thing.

[jon8christine]

Just did the same so I'll add a few comments for this transmission fluid change how to. The fill plug is located on the passenger side and is actually 17mm. Had to use a cheater wrench but wasn't too bad. The small rear compartment to drain has a small square drain plug also on the passenger side. That small compartment holds 2/3 cup, so it's worth going after (yep, had to know so I measured it). The main drain plug is a 12mm hex. If you don't have a 12mm hex on a 3/8 drive go buy one and stop using vice grips. Oil drain plug is the same. Mine are trashed from previous owners / quickie lubes.

I only had the front jacked up, pulled the fill plug, and then jacked the rear up. When I jacked the rear up fluid started coming out of the fill hole. Just an fyi as you were trying to get more fluid in by jacking the rear up. I think level will get you the 'right' amount of fluid, mine took about 1.7 quarts.

There are a bunch of threads on what fluid to use. Everyone says non-EP GL-1. My Haynes manual says Castrol GTX 20/50. Nobody had GL-1 in stock but they did have Royal Purple synthetic 75W-90 that specifically states non-corrosive to soft yellow metals (brass, bronze, copper) and safe for manual transmissions with synchronisers, so that's what I'm running. It's $23 a quart but O'Reilly had a $10 rebate and at every 18,000 miles it'll be years before I change it again.

[18Fiatsandcounting]

Thanks for that info. As for Fiat transmission oils, there are as many opinions (maybe more) than there are people giving them. Some people use a mineral based tractor oil (old Ford tractors, I believe), and that's fairly available. The EP (Extreme Pressure) are for hypoid type gears like the differential, but the sulfur additives in EP oils aren't good for transmissions with softer metals like with brass synchros. You can also purchase GL-1 online.

I'm guessing you could get more than 18K miles out of a transmission oil change, depending on how much you drive and under what conditions. For the limited amount of driving that I do on my spiders, I just check every year or two to make sure it's topped off and leave it at that. But, I'm also not the kind of guy that vacuums the dust from the refrigerator coils every couple months like the owner's manuals tell you to...!

-Bryan

[SteinOnkel]

Just did the same so I'll add a few comments for this transmission fluid change how to. The fill plug is located on the passenger side and is actually 17mm. Had to use a cheater wrench but wasn't too bad. The small rear compartment to drain has a small square drain plug also on the passenger side. That small compartment holds 2/3 cup, so it's worth going after (yep, had to know so I measured it). The main drain plug is a 12mm hex. If you don't have a 12mm hex on a 3/8 drive go buy one and stop using vice grips. Oil drain plug is the same. Mine are trashed from previous owners / quickie lubes.

I only had the front jacked up, pulled the fill plug, and then jacked the rear up. When I jacked the rear up fluid started coming out of the fill hole. Just an fyi as you were trying to get more fluid in by jacking the rear up. I think level will get you the 'right' amount of fluid, mine took about 1.7 quarts.

There are a bunch of threads on what fluid to use. Everyone says non-EP GL-1. My Haynes manual says Castrol GTX 20/50. Nobody had GL-1 in stock but they did have Royal Purple synthetic 75W-90 that specifically states non-corrosive to soft yellow metals (brass, bronze, copper) and safe for manual transmissions with synchronisers, so that's what I'm running. It's $23 a quart but O'Reilly had a $10 rebate and at every 18,000 miles it'll be years before I change it again.

There's multiple drain plugs that were used. Some are big allen, some are 17mm hex. The latter is easier to get to with the transmission in the car.

Ford Tractor Transmission oil is sold by Tractor Supply Company. Works great.

Cheers
Steiny

[DieselSpider]

My Dad brought me up old school so the first lube change on a new to me used car involves refilling it with Kerosene or Diesel Fuel, a gentle drive around the block and draining that out, repeating the flush and then after the final flush has drained for a few hours (overnight is preferable) refilling with fresh lube. Old school was to add Kerosene to you transmission and differential gear lube in the Fall and then flushing it out with more Kerosene and replacing it with straight gear lube for the Late Spring and Summer.

We get spoiled today with the greater temperature ranges of modern lubes and extended service schedules.

[Vintageant]

Who can advise what the thread is of the engine, transmission and differential drain plugs?
I know they take a 17mm wrench to undo, but wish to know the tap size so I can clean the threads while doing oil changes.
Thanks!

[tima01864]

https://www.midwest-bayless.com/p-11589 ... l-new.aspx

[DieselSpider]

https://www.midwest-bayless.com/p-11589 ... l-new.aspx

Based on that one would need a 22mm metric pipe or taper tap.

Something like this set might then take care of thread cleanup however one would want to be careful about how often or aggressive they got since once you drive a pipe tap in too deep then you have a much bigger problem to deal with.

https://www.amazon.com/Aexit-Flutes-Thr ... 77&sr=8-20

[Nut124]

Who can advise what the thread is of the engine, transmission and differential drain plugs?
I know they take a 17mm wrench to undo, but wish to know the tap size so I can clean the threads while doing oil changes.
Thanks!

Are you trying to solve a specific problem by running a tap in the threads?

I'm w DieselSpider on this - could do more harm than good. Unless there is a problem I would leave the threads alone.

[Vintageant]

How often? Well it probably has never been done since 1973, so about once every 47 years?

I have a brand new plug as shown a couple of posts above, but it will only screw in a few threads before it binds tight, and the plug is sitting very proud of the differential.

Think this is what I am looking for:

https://www.ebay.com/itm/M22-X-1-5-Metr ... 1536115003

All comments most welcome!

[SteinOnkel]

How often? Well it probably has never been done since 1973, so about once every 47 years?

I have a brand new plug as shown a couple of posts above, but it will only screw in a few threads before it binds tight, and the plug is sitting very proud of the differential.

Think this is what I am looking for:

https://www.ebay.com/itm/M22-X-1-5-Metr ... 1536115003

All comments most welcome!

If there is clearance and it seals, leave it alone. It could well be pipe thread.