synthetics

#1
Is anyone running synthetic in their gear boxes?

If so has it improved the shifting at all, many moons ago I put Redline tranny fluid in my Westy and it was a noticeable improvement in the shifting of it but heard some grumblings about additional wear which sounds odd??
 
#2
I run Mobil synthetics in my transmission, differentials and portals. I can't say that I have noticed any appreciable differnece in shifting or sound levels and I have not done any temperature monitoring, but it gives me peace of mind knowing that I am using "better" lubricants.
 
#3
Thanks Greg, Ive never looked into the properties of Mobil verses Redline but the Redline made shifting on the westy noticeably better and Im starting to get some shifting issues, not bad just needing to shift slower to not get a slight chunking when going into gear, sooo....no one using Redline? Anyone doing anything different to improve shifting other than double clutching?
 

kerry

Expedition Leader
#4
Do you have an adjustable clutch on yours? My 99FG does. A rod on the slave cylinder. I was having slight trouble going into 2nd from a stop and some grinding in reverse sometimes until I lengthened that rod to get more release.
 

Choff

Adventurer
#5
I use Mobil I for my oil and have changed to synthetic in Trans and engine , seams to me it make for a better running when real cold.
I gets down to below zero during winter in Wisconsin!!!
2005 AWD GMC Savana van with 182,000 and all original engine, running great
 
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#6
Do you have an adjustable clutch on yours? My 99FG does. A rod on the slave cylinder. I was having slight trouble going into 2nd from a stop and some grinding in reverse sometimes until I lengthened that rod to get more release.
Theres some adjustment on it, its not too bad right now and I will adjust it before the next trip, but I still like the idea of synthetic in the transmission to help smooth out the shift some, surprised that there arent more on here that have gone the synthetic route? Looking for some one to say " dont do it man!!" or " do it man!"
 
#7
I use Mobil I for my oil and have changed to synthetic in diff & rear end , seams to me it make for a better running when real cold.
I gets down to below zero during winter in Wisconsin!!!
2005 AWD GMC Savana van with 182,000 and all original engine, running great
For sure good for the cold.
 

pugslyyy

Robinson Fuso
#8
Theres some adjustment on it, its not too bad right now and I will adjust it before the next trip, but I still like the idea of synthetic in the transmission to help smooth out the shift some, surprised that there arent more on here that have gone the synthetic route? Looking for some one to say " dont do it man!!" or " do it man!"
I'm not a great believer in running synthetics unless the vehicle was designed to benefit from it. I've seen too many leaky seals, etc. on older vehicles. I just do regular fluid changes and give everything a chance to warm up.
 
#9
Theres some adjustment on it, its not too bad right now and I will adjust it before the next trip, but I still like the idea of synthetic in the transmission to help smooth out the shift some, surprised that there arent more on here that have gone the synthetic route? Looking for some one to say " dont do it man!!" or " do it man!"
Ok..... I'll bite. Don't use synthetic in the rear differential as it interferes with proper operation of the limited slip! Everywhere else should be good. I prefer to use conventional and change it more often as I am more concerned about contamination from lots of dirt work and water crossings.

Allan
 
#10
Not a Japanese heavy truck (at least not by you guys' standards, LOL!) but FWIW I've used redline MT-90 in my BJ74 Land Cruiser's 5 speed tranny (it specs a GL-4) and yes it made a very noticeable difference in shifting. I used it my my BJ70 before it (same H55F trans) and it made a real difference in shifting it too.
It's the only synthetic I use in that truck, the diffs and t-case get cheap Wally World Supertech 80-90 and get changed often.

Oh, and I use Redline Shockproof Heavy (the stuff that looks like Pepto Bismol) in my old harley shovelhead transmission, that stuff is awesome!
 
#11
Only complaint I've heard from Longhaul truck guys it the synthetic doesn't like humidity or any form of moisture ingress, worse than mineral oil. So while it is smoother running it isn't longer lasting in those conditions and is far more expensive.
 
#12
Not a Japanese heavy truck (at least not by you guys' standards, LOL!) but FWIW I've used redline MT-90 in my BJ74 Land Cruiser's 5 speed tranny (it specs a GL-4) and yes it made a very noticeable difference in shifting. I used it my my BJ70 before it (same H55F trans) and it made a real difference in shifting it too.
It's the only synthetic I use in that truck, the diffs and t-case get cheap Wally World Supertech 80-90 and get changed often.

Oh, and I use Redline Shockproof Heavy (the stuff that looks like Pepto Bismol) in my old harley shovelhead transmission, that stuff is awesome!
Thanks, That was my experience too, helped smooth out the shifting. I may just go ahead and put some in if it is compatible with my truck.
 
#13
Only complaint I've heard from Longhaul truck guys it the synthetic doesn't like humidity or any form of moisture ingress, worse than mineral oil. So while it is smoother running it isn't longer lasting in those conditions and is far more expensive.
Was that in the transmission or engine?