15w 40 rotella? firefighter?

[deputycrawford]

Thanks Chryco!! Now you started something...My wife wants me to use the bag over my head. What a friend you are....

[Chryco Psycho]

Thanks Chryco!! Now you started something...My wife wants me to use the bag over my head. What a friend you are....

Ooops

[Chryco Psycho]

GL5 & most syntheic oils seem to be a problem with being too slippery
there are synthetics designed to be used in manual trannys , Redline , Mopar both have synthetic Manual trans lube
or just use the proven 80-90w , not being an oil engineer I have no idea if or why detergents would make syncros not work

[rt green]

well, what i understood was the syncros are sort of cup shaped,well kind of. what they do is when you are changing gears, you have well let say 2 gears spinning. the syncro is in the middle. the 1st gear is spinning at a high rate of speed. the 2nd one, the one you want to go into, is spinning but at a much lower rate of speed.  what will happen is the syncro{brass cup} will grab the inside of the gear and speed up the gear by way of interferance fit. that way the 2 gears will mesh without grinding. remember the old,old pickups didnt have them, and you had to blip the throttle for a smooth shift.      what i understand was the gl5 80-90w was to slippery and the brass syncros wouldnt grip the gear good enough to get it spinning fast enough. i'm not a 4 speed expert and was wondering if anyone on this board has ran into this.

[Ghoste]

Could be?  I'm no engineer either but maybe that is one of the reasons the super stock guys with no synchros can get away with running automatic tranny fluid in their four speed boxes?

[BrianShaughnessy]

Many newer manual trans such as the BW T-5 and T-56 do not use brass synchros.     The synchros are made of the same stuff that automatic trans bands are made of and  these trans came factory filled with dextron of whatever the latest and greatest was at the time.   Some older versions of the T-5 used brass synchros and used either motor oil or a regular gear fluid.   A cheezy halfazz backyard method to getting an old T-5 to stop grinding was to use ford type auto trans fluid.
My Tremec uses GM synchromesh fluid at $11 / quart. 

[Chryco Psycho]

I have run into problems using synthetic oil
the syncro is a Cone shape & the gear has a reverse cone , the syncro also has grooves in the cone to give the oil  a place to go , newer syncros also have slots cut across the grooves & up the cone to help bleed out the fluid under the syncro

[derailed]

Is there any type of detergent in Rotella 15-40 that would be harmful on a higher mileage engine. Only reason im asking is because I went out and bought some for the oil change in my charger and the guy there told me to think twice about it because of the detergent in it. I really couldnt see where hes coming from because they run this stuff in big trucks with a million miles on them but maybe thats because its been in there since day one?

[firefighter3931]

Derailed, i run Rotella in my daily driver pickup which has close to 180K miles on it. No problems. This is a gas engine btw. 


Ron

[derailed]

Thats what I figured, I just wanted to get your opinion on this guys comment. I was running Penzoil 20/50 in the summer and 10/40 in the fall. I figured id use the Rotella being that its pretty popular here. Thanks

[DW]

There was an article in the June 2006 Hot Rod that talked about today's oils not having the additives (zinc, if I remember) required to properly cushion the flat tappet to cam surface.  They recommended Rotella as well.  The also said that some racing oils like Quaker States Q-Racing also have additives to protect flat tappets.

[Chryco Psycho]

Rotella does have a rating for SL/Sm gas engine application on it