Old school 4 on the floor help me decide

FCD

FCD

Joined
Oct 22, 2015
Messages
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Location
Mallorca, Balearic Islands, Spain
After more than 300k miles and 45 years of faithful use the gearbox in my Capri is finally giving signs it is about to go to gearbox heaven. Thankfully i have a good friend who has and identical one to mine with 54k miles and in good condition and who will sell it to me and we'll chuck it in with a new clutch and single piece driveshaft grin Bottom line is i want it to last as long as possible. Which of these would you pick for a manual transmission that specifies 80W GL-4 gear oil. 1 - 80W GL-4 Conventional : Visc @ 40C = 84.4 Visc @ 100C = 10.2 VI = 102 2 - 75W-80 GL-4 Conventional : Visc @ 40C = 47 Visc @ 100C = 8.1 VI = 146 2 - 75W-85 GL-4 Syn-Blend : Visc @ 40C = 72.4 Visc @ 100C = 11.7 VI = 157 Price for all is aboout the same.
 
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Lots of stuff in play. Forty five years ago they might not have entertained a multi vis for a transmission. However, Spain doesn't get real cold like up here. I like syn fluids or syn blends but I'll take door number one, the 80 grade conventional which was probably closest to the stuff that CT-8 alluded to. I had a 76 version of this car, black with gold wheels, four speed, dual exhaust. Back in the mid 80's guys would put a hot cam in them an cruise the streets of Vancouver, Canada. They are long gone now.
 
Originally Posted by atikovi
Why not just take it apart and replace the bearings and syncros? No more complicated than rebuilding a carburetor.
The rebuild kit, costs more than what this friend of mine is selling me his gearbox for.
 
Originally Posted by FordCapriDriver
Originally Posted by atikovi
Why not just take it apart and replace the bearings and syncros? No more complicated than rebuilding a carburetor.
The rebuild kit, costs more than what this friend of mine is selling me his gearbox for.
But then you know it's good for another 300K. A used transmission you never know until you put it in, no matter what people say about it. Do it once, do it right.
 
Originally Posted by Yah-Tah-Hey
Rebuild what you have and know what you have.
^Just retain the whole old gearbox. For 300k from now, when you might need the synchros & replace a chipped gear or three.: )
 
Originally Posted by atikovi
Originally Posted by FordCapriDriver
Originally Posted by atikovi
Why not just take it apart and replace the bearings and syncros? No more complicated than rebuilding a carburetor.
The rebuild kit, costs more than what this friend of mine is selling me his gearbox for.
But then you know it's good for another 300K. A used transmission you never know until you put it in, no matter what people say about it. Do it once, do it right.
I've driven the car with the gearbox in question,it works perfectly, he simply swapped it for a 5 speed to drop down the revs on motorway cruising.
 
You're in a hot climate so the heavier oil is better or in lieu of that the semi syn 75w-85. I'd use the OEM spec 80w conventional you put at the top.
 
Pick one with the highest [email protected]*C in 80W (84.4 cSt) among your options . Personally I would 'upgrade' to a 80W90 of around 150ish cSt , though 75W90 of about 100ish cSt is considered an upgrade too in your context .
 
Thank you all for the input. I had 75W-90 GL-4 in it for about 3 years ( Ford's own stuff ) It was ok-ish but cold shifting was a bit stiff. It's perfect with the 80W I have managed to found that Ravenol, makes an oil called MZG 80W. It in fact meets Ford SQM-2C-9008-A, which is the original spec for this gearbox. And it's cheap, 7.78€ / Litre
 
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I would've thought your ambients should be fine with 80W90 . At least that's the case with me .
 
Synthetic or Mineral 80W-90? I've never had synthetic in the gearbox, only mineral 75W-90 and 80W We sure have colder winters here in the Mediterranian than in Malaysia, today for example it hasn't gone above +10C all day. Many winter mornings the temperature is 0 to +5c, and occasionally even -2 or -3C at night.
 
Originally Posted by FordCapriDriver
Thank you all for the input. I had 75W-90 GL-4 in it for about 3 years ( Ford's own stuff ) It was ok-ish but cold shifting was a bit stiff. It's perfect with the 80W I have managed to found that Ravenol, makes an oil called MZG 80W. It in fact meets Ford SQM-2C-9008-A, which is the original spec for this gearbox. And it's cheap, 7.78€ / Litre
There you go. No need to overthink things.
 
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