- Jun 5, 2002
- Iowegia - USA
Thanks for the clarification. One more question: Were you measuring the actual fluid temperature or the transmission's case temperature?
Originally Posted by 2009ram2500
1) I ran a 5 quarts (5/8 or 62.5%) Mobile 1 Synthetic Transmission Fluid 50 SAE (the one in the picture) which has a manf tested viscosity of 132CsT at 40c / 17.5CsT at 100c BLENDED with 3 quarts (3/8 or 37.5%) Amsoil Manual Synchromesh Transmission Fluid (the one in the picture) which has a manf tested viscosity of 87.6CsT at 40c/ 13.9CsT at 40. This blends weighted average viscosity is 88.76CsT at 40c / 14CsT at 100c. I ran this blend for 25,000 miles in my 2009 G56. This blend would max out at 180F to 190F in about 200 miles at 100F ambient temps. Here's my pan results after 25K on this blend https://www.cumminsforum.com/forum/...
2) at 50K I switched out the trans fluid to the Amsoil Manual Transmission and Transaxle Gear Lube 75W-90 (MTG 75W-90) (the one in the picture and the one I referenced in my "other" thread on here which has a manf tested viscosity of 87.6CsT at 40c/ 13.9CsT at 40c. I've ran this for 5,000 to -8,000 miles and running this MTG I tracked the results making the same trip under the same load conditions and similar ambient temps
Here are my temp/ miles results with the MTG 75/90:
30 miles to get to 140*
100 miles to get to 160*
140 miles to get to 180*
180 miles to get to 200*
200 miles to get to 220* ambient started at 63F and got to a max of 92F around mile 200
3) Additionally I ran the MTG on a different trip pulling a different trailer and got these results (which differ from the results above):
Now on my last winter trip with the MTG 75/90 it was 63F outside and I did 240 miles and trans never got above 200F. On the way back ambient temps where 82F and temp remained 180F until I pulled the white water grade outside Palm springs CA headed west (about 3 miles) at about 65-70mph with the 7k box trailer. As soon as I started the grade temps started climbing and didn't stop until about 220F which is where they level off and seem to peak out with the MTG 75/90 On a side note; if I shut off the truck, the trans cools down from 220F to 160F in about 12 minutes.
1) Both the MTG and the 3/5 blend have the same viscosity so the differences in temperature and shifting characteristics can only be from differences in additive packages not viscosity.
2) The MTG acts different in different ambient temperatures and shear loads. EG: It stays cool (180F) under 80F ambient but heats up very fast when over 90F ambient and under high shear loads.
3) The Blackstone anayslsis of both the Delvac 50 SAE & the Amsoil Synchromesh 5W-30 are posted in this thread but I do not know how to calculate the actual additive content based on the weighted averages of my blend to get at least a close ballpark of what was in the 3/5 (37.5%/62.5%) blend I ran and tested for 25K miles.
Given these results, here are my questions
1) why does the MTG get hot so much faster than the Delvac mix despite having the same viscosity?
2) what causing the MTG fluid temps to rise under load VS. running flat and why does a 20 degree increase in ambient temps raise the MTG fluid temp so much?
3) Why can I not get it in to gear above 210/220F with the MTG 75/90 even though it's thinner when hotter ( aka it's not the viscosity)?
4) Is it better to run the manual trans at 180/190F with the Delvac/Synchromesh mix OR 220F with the MTG as there are no clutches ( like in an auto trans), since it's all gears and brass synchros?