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| | | | Joined: Oct 2012 Posts: 85 Shop Shark | | Shop Shark Joined: Oct 2012 Posts: 85 | I have a 1953 truck with a 235 engine in my truck along with a 3 speed manual transmission. I've rebuilt the transmission and changed gasket, seals etc on the engine. Now I'm ready to put the oil back in.
Is it better to refill using synthetic oil in the engine and transmission?
Someone suggested synthetic oil may damage the brass found in the transmission. What about in the engine?
Last edited by DJRoy; 06/07/2013 3:35 PM.
| | | | | Joined: Aug 2005 Posts: 6,377 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,377 | For the .02 that my opinion is worth go with the synthetic if that's what you want to use. I'm not aware of any way it can damage your engine. I've not heard of synthetic damaging transmissions either. If someone has a link to information saying that it does I'd be interested in reading it. Synthetic in transmissions info from Mobil.
Last edited by Tiny; 06/07/2013 3:53 PM. Reason: Added link
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| | | | | Joined: Sep 2011 Posts: 1,458 'Bolter | | 'Bolter Joined: Sep 2011 Posts: 1,458 | The only issue with synthetic is it will degrade some older gasket materials & sealants (RTV) causing leaks.
BC
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Retired GM dealer tech. 1980 - 2022
| | | | | Joined: Aug 2005 Posts: 6,377 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,377 |
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
| | | | | Joined: Oct 2012 Posts: 85 Shop Shark | | Shop Shark Joined: Oct 2012 Posts: 85 | I went to the local auto store to purchase tranny oil. I've decided to go synthetic for the engine and regular SAE 90 for the tranny.
What they had was SAE80W-90 oil. Will that do or is the 80w to thick of an oil? Specs for that tranny states it should be straight SAE 90. | | | | | Joined: Nov 2006 Posts: 2,544 Shop Shark | | Shop Shark Joined: Nov 2006 Posts: 2,544 | I've heard of problems with our older transmissions not shifting as good with the synthetic oil in them. | | | | | Joined: Sep 2006 Posts: 3,596 'Bolter | | 'Bolter Joined: Sep 2006 Posts: 3,596 | From Novak Transmissions one of the premier builders of transmissions in the business.
When filling your 420 with gear oil, we recommend that you select a conventional mineral oil or a para-synthetic in lieu of a full synthetic oil. Properly assembled manual gearboxes do not have the thermal strains seen by combustion engines or hypoid gears. Synthetic fluid in these gearboxes, while not harmful, is probably an economic waste.
Hypoid gear oil is sulphurized higher than transmission oil and can be mildly corrosive to the non-ferrous alloys used for synchros, bushings and thrust washers in these transmissions.
An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contradicted unless you operate your vehicle in a very warm environment. | | |
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