{"id":175661,"date":"2025-11-03T13:30:00","date_gmt":"2025-11-03T10:30:00","guid":{"rendered":"https:\/\/bukvaved.top\/v-chjom-raznica-mezhdu-maslami-75w80-i-75w90\/"},"modified":"2026-10-28T14:04:49","modified_gmt":"2026-10-28T11:04:49","slug":"what-039-s-the-difference-between-75w80-and-75w90-oils","status":"publish","type":"post","link":"https:\/\/bukvaved.top\/en\/v-chjom-raznica-mezhdu-maslami-75w80-i-75w90\/","title":{"rendered":"What is the difference between 75w80 and 75w90 oils?"},"content":{"rendered":"<p><strong>75W80 and 75W90 oils differ in viscosity at operating temperature: 75W90 is thicker at 100\u00b0C, while 75W80 is thinner. At low temperatures, both oils perform equally well, as they share the same winter rating of 75W.<\/strong> In practice, manufacturers of many new manual transmissions recommend 75W80, while 75W90 is more commonly used in transmissions and axles with higher loads. The vehicle manufacturer&#039;s specifications, not the number on the label, are decisive.<\/p>\n<p> To sum it up<\/p>\n<ul>\n<li> <strong>The same winter class:<\/strong> \u00ab75W\u00bb means the same requirements for frost resistance for both oils (up to -40\u00b0C according to the SAE J306 standard).<\/li>\n<li> <strong>Different viscosity at 100\u00b0C:<\/strong> for class 80 - from 8.5 to less than 11.0 mm\u00b2\/s, for class 90 - from 13.5 to less than 18.5 mm\u00b2\/s.<\/li>\n<li> <strong>75W80 oil<\/strong> reduces resistance and makes gear shifting easier, and <strong>75W90 oil<\/strong> Forms a thicker oil film under high loads.<\/li>\n<li> <strong>Not only viscosity is important, but also the API quality class (GL-4, GL-5) and car manufacturer standards<\/strong> .<\/li>\n<\/ul>\n<h2> What do 75W80 and 75W90 mean?<\/h2>\n<p> The viscosity of transmission oils is described by the standard <strong>SAE J306<\/strong> . Both oils are <strong>all-season<\/strong> , so the designation consists of two parts:<\/p>\n<ul>\n<li> <strong>75W<\/strong> - This is winter oil (W stands for &quot;\u00ab <em>winter&quot;\u00bb<\/em> ). According to the SAE J306 standard, the viscosity of 75W oil must reach 150,000 mPa s only at temperatures no higher than -40\u00b0C. This allows it to remain sufficiently fluid when starting the engine in freezing conditions. In this regard, 75W80 and 75W90 oils are also considered &quot;winter&quot; grades.<\/li>\n<li> <strong>80 or 90<\/strong> - this is the summer class, that is, the kinematic viscosity at <strong>100 \u00b0C<\/strong> . This is the whole difference between these oils.<\/li>\n<\/ul>\n<p> Transmission oil viscosity grades are not comparable to motor oil viscosity grades. A 75W90 transmission oil is only a few times thicker than a 5W30 motor oil, and the numbers in both standards (SAE J306 and SAE J300) mean different things.<\/p>\n<h2> The difference in viscosity is 75W80 and 75W90 in numbers.<\/h2>\n<p> According to the 2019 revised SAE J306 standard, grade oil <strong>80<\/strong> has a kinematic viscosity of 8.5 to less than 11.0 mm\u00b2\/s (cSt) at 100\u00b0C. Class oil <strong>90<\/strong> has a kinematic viscosity from 13.5 to less than 18.5 mm\u00b2\/s. Between them lies grade 85 oil (from 11.0 to less than 13.5 mm\u00b2\/s), which is why 75W85 oils are also available on the market.<\/p>\n<p> <strong>Therefore, warmed up 75W90 oil is much thicker<\/strong> . It creates a thicker lubricating film between gear teeth and bearings, which helps under high loads and high operating temperatures. Oil <strong>75W80 creates less resistance<\/strong> , so the transmission loses less energy &quot;mixing&quot; the oil, and gear shifts are smoother, especially before the transmission warms up. Automakers choose thinner oils, in part to reduce friction losses.<\/p>\n<h2> Comparison Chart: 75W80 vs. 75W90<\/h2>\n<table>\n<tbody>\n<thead>\n<tr>\n<th> Characteristic<\/th>\n<th> 75W80<\/th>\n<th> 75W90<\/th>\n<\/tr>\n<\/thead>\n<\/tbody>\n<tbody>\n<tr>\n<td> <strong>Winter Course (SAE J306)<\/strong><\/td>\n<td> 75 W: 150,000 mPa s at \u2264 -40\u00b0C<\/td>\n<td> 75 W: 150,000 mPa s at \u2264 -40\u00b0C<\/td>\n<\/tr>\n<tr>\n<td> <strong>Viscosity at 100 \u00b0C<\/strong><\/td>\n<td> from 8.5 to &lt;11.0 mm\u00b2\/s<\/td>\n<td> from 13.5 to &lt;18.5 mm\u00b2\/s<\/td>\n<\/tr>\n<tr>\n<td> <strong>Density in the workplace<\/strong><\/td>\n<td> Rarely<\/td>\n<td> Thicker<\/td>\n<\/tr>\n<tr>\n<td> <strong>Resistance in the box<\/strong><\/td>\n<td> Less<\/td>\n<td> More<\/td>\n<\/tr>\n<tr>\n<td> <strong>Cold shift<\/strong><\/td>\n<td> Usually lighter<\/td>\n<td> It might be a little more difficult to warm up.<\/td>\n<\/tr>\n<tr>\n<td> <strong>Typical use<\/strong><\/td>\n<td> Manual transmissions are found in many modern passenger cars<\/td>\n<td> Heavy-duty transmissions and axles, delivery vans, SUVs.<\/td>\n<\/tr>\n<tr>\n<td> <strong>Quality classes<\/strong><\/td>\n<td> Commonly labeled as GL-4, GL-5, or GL-4\/GL-5<\/td>\n<td> Commonly labeled as GL-4, GL-5, or GL-4\/GL-5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2> GL-4 or GL-5 is the second important difference on the label.<\/h2>\n<p> Besides viscosity, you should also check <strong>API quality class<\/strong> . Oil <strong>GL-4<\/strong> Designed for medium-duty transmissions such as typical manual transmissions with synchronizers. <strong>GL-5<\/strong> Contains more extreme pressure additives and is used for transmissions operating under severe conditions, such as hypoid gears in axles.<\/p>\n<p> GL-5 oil isn&#039;t always &quot;better&quot; than GL-4. Some transmissions require GL-4 oil because the different additive package can impair synchronizer performance. There are also oils labeled <strong>GL-4\/GL-5<\/strong> , approved for both types of application. Therefore, two 75W90 oils can be suitable for different transmissions.<\/p>\n<h2> 75W80 or 75W90 \u2013 which oil to choose?<\/h2>\n<ul>\n<li> <strong>Start with the manufacturer&#039;s manual or catalog<\/strong> . They indicate viscosity, API grade, and often a company standard, such as the VW, PSA, or Ford specification number. Look for oil that meets or is approved for this standard.<\/li>\n<li> <strong>Don&#039;t just change oil brands.<\/strong> A thicker 75W90 oil in a transmission designed for 75W80 may make shifting difficult, especially in winter. A thinner oil in a transmission requiring 75W90 may provide less protection for gears and bearings under high loads.<\/li>\n<li> <strong>The drive shaft is different from the gearbox.<\/strong> In rear-wheel drive or all-wheel drive vehicles, the shaft often requires a different oil (such as 75W90 GL-5) than the transmission.<\/li>\n<li> <strong>For automatic transmissions, DSG and CVT<\/strong> Completely different fluids are required (ATF, DSG\/CVT fluids). 75W80 and 75W90 fluids are not suitable for them unless the manufacturer specifically specifies them for a specific unit.<\/li>\n<li> If in doubt, contact an authorized service center or a reputable repair shop. The cost of an oil change is minimal compared to the cost of a transmission repair.<\/li>\n<\/ul>\n<h2> Frequently Asked Questions (FAQ)<\/h2>\n<p> <strong>Can I use 75W90 oil instead of 75W80?<\/strong><\/p>\n<p> Only if the vehicle manufacturer allows the use of both viscosity grades in a given transmission. In a transmission designed for 75W80 oil, a thicker oil may make shifting difficult, especially in winter. It&#039;s safest to stick to the specifications in the owner&#039;s manual.<\/p>\n<p> <strong>Which oil is thicker: 75W80 or 75W90?<\/strong><\/p>\n<p> The 75W90 slurry has a higher viscosity at operating temperature: its viscosity at 100\u00b0C is from 13.5 to less than 18.5 mm\u00b2\/s, compared to 8.5 to less than 11.0 mm\u00b2\/s for the 80 grade. At low temperatures, both slurries meet the same requirements of the 75W grade.<\/p>\n<p> <strong>Can you mix 75W80 and 75W90 oils?<\/strong><\/p>\n<p> The transmission is filled with oil that meets the manufacturer&#039;s specifications. Mixing oils of different viscosities and qualities results in oil with unpredictable properties. It&#039;s best to use the same product when topping up and replace the entire oil during a change.<\/p>\n<p> <strong>Is 75W90 oil better than 75W80?<\/strong><\/p>\n<p> In general, there is no best oil; there is only the right oil for a specific transmission. 75W90 oil performs better in transmissions designed for higher loads, while 75W80 oil performs better in transmissions designed for thinner oil and lower friction.<\/p>\n<p> <strong>What does the letter W mean in oil marking?<\/strong><\/p>\n<p> The letter W comes from the English word &quot;winter&quot; and denotes the winter grade. The number before the W (here 75) describes the oil&#039;s behavior at low temperatures, and the number after the hyphen (80 or 90) indicates its viscosity at 100\u00b0C.<\/p>\n<h2> See also<\/h2>\n<ul>\n<li> What is the difference between 5w30 and 5w40 oils?<\/li>\n<li> What is the difference between 5w40 and 10w40 oils?<\/li>\n<li> What is the difference between 2T and 4T oil?<\/li>\n<li> What is the difference between synthetic and semi-synthetic oil?<\/li>\n<li> What is the difference between the M32 and F40 gearboxes?<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>75W80 and 75W90 oils differ in viscosity at operating temperature: 75W90 is thicker at 100\u00b0C, while 75W80 is thinner. At low temperatures<\/p>","protected":false},"author":1,"featured_media":175662,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[67,20],"tags":[70],"class_list":["post-175661","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-vopros-otvet","category-fakty","tag-chem-otlichaetsya"],"_links":{"self":[{"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/posts\/175661","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/comments?post=175661"}],"version-history":[{"count":1,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/posts\/175661\/revisions"}],"predecessor-version":[{"id":175663,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/posts\/175661\/revisions\/175663"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/media\/175662"}],"wp:attachment":[{"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/media?parent=175661"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/categories?post=175661"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bukvaved.top\/en\/wp-json\/wp\/v2\/tags?post=175661"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}