In an effort to increase towing reliability and wear on my truck, I would like your input on sythetic fluids.

I will be changing the trans fluid, rear diff fluid, and engine oil. Should I switch to synthetic for all three?

 

Do any of the above mentioned leak as of right now? Miles on the truck? And leave the trans mission out of the question. Mercon ONLY. No synthetic stuff.

 

Agree and thank you. You're very right, a quick search clearly showed me Mercon V spec only.

no leaks.

 

If nothing is leaking you can go ahead and try the synthetic. Just know there is a chance you will see oil leaks after the change. Synthetic fluid slips through small space much easier than conventional oil. Because if this, a very small, possibly unnoticed leak can be come worse after the change. I changed to synthetic knowing my rear main seal was leaking. It still does, but I'm not sure if it has sped up. I know it's there and have more oil to add so it doesn't bother me.

 

Okay thank you. I have heard exactly what you are talking about. Love the idea of staying with regular engine oil anyway.

That leaves the rear differential. I hear great things on this forum about synthetic rear diff fluid. What do you all think?

 

Never tried it... I just used cheap conventional stuff when I did mine.

 

You can totally use a synthetic oil in. The transmission.. Engine oil and differentials are where synthetics really shine..

Want some real good info on oil you can check out bobistheoilguy.com

Personally I have all Amsoil everything in my truck except trans cause it only has 10k on it.. In a couple thousand miles it'll be swapped over.. And yes I'm an Amsoil dealer but that's not the only reason why I use it. I choose to use the best to make my truck love as long as possible.. And it's not stock and I beat the crap out of it

 

It is not recommended to use synthetic oils in the differential if you have a clutch type locker.

Best way to do a transmission fluid change is to drain the pan and the converter (most converters have a plug) and just refill it with Mercon 5. The synthetic types, like Mobil 1 are very good but they are more $$$

 

Synthetic fluid is fine in a diff with a clutches LS.. You just have to do just like a conventional gear oil, is limited slip additive..

 

most synthetic gear oil has the LS additive already for clutch pack differentials. in fact, i cant name one that doesnt have it. synthetic is the way to go; it will prolong the life of bearings and moving parts, decrease temp's, increase mpg. its expensive, but its well worth it if youre keeping the truck.

 

Yes they do, but sometimes not a strong enough concentrate to make the clutch packs happy..

 

its rare to get chatter with synthetics, but possible absolutely.

 

I run synthetic in mine, just changed the oil and diff fluid. Havent touched the trans yet. Some people have oil leak horror stories when they switch to synthetics, others don't I've never seen it happen before, and if that's the case just run a high-mileage synthetic. I run Castrol Edge in my truck and Rotella T6 in my Subaru.

 

That's cause people don't realize the synthetic flows better and is a more perfect molecule it'll find all books and crannies like bearings etc.. Including gasket cracks, that sometimes a conventional can't make it through.. It's not the synthetics fault.. You have a leak, fix it..

 

Yup, typically the factory equipped rear main leak
Mines got it but it had it before I bought the truck. It's not a fun thing to change so I live with it.