: Questions about Rear end and tranny fluid



svtbolt2001
08-19-08, 03:03 PM
Ok so I am planning on replacing my fluids this weekend but have some questions first. I am planning on using Royal purple products so here goes.

Tranny
Is Synchromax just an addictive that gets added to other transmission fluid or is it a stand alone product? Do I need 4 quarts of synchromax or am i supposed to be adding it to another product?

Rear Diff
After reading the FAQ, i noticed limited slip additive being used. Is this needed or would i be able to just use 3 quarts of max gear?


Thanks

CTSV_510
08-19-08, 03:16 PM
Rear Diff
After reading the FAQ, i noticed limited slip additive being used. Is this needed or would i be able to just use 3 quarts of max gear?


You only need the additive if the gear oil doesn't already have it.

It only take about 1 1/4 quarts, but get three quarts and you'll be good for 2 changes.

svtbolt2001
08-19-08, 03:24 PM
ok so i need a gear oil, not the additive unless needed? Glad i asked.

Is that the same for the tranny?

ctsv154
08-19-08, 03:24 PM
You will need 4 quarts of syncromax for the tranny as it is the transmission fluid and not just an additive. Also the rear end needs two quarts and you wont use all of it. People have had problems with noise after using only rp in the diff so they recomend using the additive.

svtbolt2001
08-19-08, 03:34 PM
ok so just called Royal Purple and learned that their products are all ready to use oils and not additives.

svtbolt2001
08-19-08, 03:36 PM
You will need 4 quarts of syncromax for the tranny as it is the transmission fluid and not just an additive. Also the rear end needs two quarts and you wont use all of it. People have had problems with noise after using only rp in the diff so they recomend using the additive.

Thanks for the heads up, I just got a new rear end so I may just leave it alone for now.

lollygagger8
08-19-08, 03:51 PM
I JUST changed my trans fluid with Mobil 1 ATF fluid this weekend. It shifts MUCH better than DexronIII. Some people use the RP Syncromax in the trans but I like Mobil 1. It takes 4 full quarts. Amsoil is another good choice, but harder to get.

I've heard that RP doesn't quiet down the diff....if yours is a newer model, it'll be noisy (aka whiney b*tch)
I use RedLine 75w90 and it quieted mine right down, AND it has additive in it. <- plus it's cheap!
I used GM garbage at $24/qt and the additive at another $8 and it was noisy as all get out.

svtbolt2001
08-19-08, 04:05 PM
Has anyone tried Lucas rear end lube?

ichpen
08-19-08, 04:24 PM
COnfused here :) You talk rear end then tranny... Based on my understanding, transmission fluid (Mobil 1 ATF, Amsoil ATF, RP (whatever it's called)) goes in your transmission (front).

Gear 'oil' (your 75W-90 Amsoil for example) goes in your diff. Slip lock diff additives are mixes with your gear oil (NOT your tranny fluid). These are axle lubricants which is why you may need slip lock diff additives.

I'm also going to be changing fluids this weekend. All amsoil stuff (purely as it's easier to find in Canada than RP).

I have 75W-90 + slip lock for the diff.
Amsoil ATF for the tranny.

I didn't think Synchromesh (Amsoil, RP etc) was applicable to our vehicles given that it may add noise rather than remove it.

ctsv154
08-19-08, 05:57 PM
Syncromax is manual transmission fluid and goes in the tranny and I cant say I have ever heard of a noisy transmission because of one fluid or the other.

The diff noise because of rp is the clutch packs in the LSD. The additive is a friction modifier to keep the clutch packs from chattering. People have complained of clutch pack chattering during slow speed turns using only rp in the diff with no additive.

lollygagger8
08-21-08, 01:16 PM
Save some money and use RedLine 75w90 in the diff.....quiet it down, and dont have to use additive! Again, I've never heard of anyone using RP saying their diff was quieter afterwards.
Ya syncromax is for trans (diffs dont have synchro gears!) I heard there was a mix of Amsoil ATF Fluid and Severe Gear Oil 75w90 but I dont dont know the ratio.