ShaneM

ive searched a million threads and cant find what i am looking for. we have talked about this a million ties but im not finding specific part numbers. im heading out for some maintenance on teh boss ahead of the track sat like right now. i cant for the life of me find the thread with teh specific brand and quantity of fluids that work best for the boss rear end and transmission to stop clunking and such.

someone please post up those numbers or link me to the post i cant seem to find, thanks! please note how much i need to get of each too

P0 Corsa

Here is a suggestion-
Why not consult the OWNERS MANUAL?
All the Ford recommended fluids are listed for exactly the purpose you require.

ShaneM

Not wanting the ford stuff. Looking for the redline or royal purple stuff people are changing to.

AlsCobra

I'm not sure what is being used in the Boss trans. I'm running royal purple synchromesh. I can probably get you the part # if you need it.

ShaneM

Thanks man i found the diff oil. Not sure about the tranny fluid yet

nota4re

Shane, do yourself a big tabor and order one of these to do the diff and tranny fluid changes. It will make your life soliloquy much easier!! http://www.cooltechllc.com/jeep/jk_lube_mover.shtml

AlsCobra

I'm running synchromesh in my T56. Found out about it on the SVTP site. Seems like everyone is running that stuff in their trans.

5 DOT 0

From another member:

Now I have always run Redline gear oil and transmission fluid in my racecars, and am doing so on the Boss. Lightweight Shockproof for the Torsen, which was recommended by both Redline and Torsen, and MTL for my transmission, which has had ZERO issues since changing, and shifts unbelievably smooth. Highly recommended.

http://www.redlineoil.com/product.aspx?pid=43&pcid=8

3.0 qts

http://www.redlineoil.com/product.aspx?pid=45&pcid=7

2.75 qts

ShaneM

Thanks guys i didnt get the trans done but went to royal purple in the diff

BlackMamba03

Transmission - Redline MTL or Royal Purple 75w90 gear oil

Rear end - Royal Purple 75w140 for those who are curious

Krnnerdboy

Excellent! Ill be running redline mtl and light weight. As for engine oil I'm running castrol 5-50. It was on sale @ pepboys for $5 a quart!!!

Side note, my oil at 1k mi looked like my oil at 15k mi. I'm glad I did the break in oil change

Dean#4AI

Dang, wish I would have had that about a week ago. The rear end fluid is a slimy mess!

ShaneM

well i decided to go back and get the trans fluid swap done with the mtl. wow what a difference. my transmission crunched worse than i though after moving to the MTL it's so smooth. it is well worth the time and effort to swap to mtl guys.

adam81

Agree.....I have changed out all he fluids twice now, and about to do it again. I was just about to look for something like this. Problem solved......... Thanks Kendall

adam81

I use all motorcraft fluids. Anyone have any proof or data that this stuff isn't any good or the product you are using is better.....

m4reapr

no proof but for me the reasoning for a non-oem diff. gear oil is that they already contain friction modifier

for the trans. fluid it was to split the difference in viscosity due to possibly having cold shifting effort increase - Ford even flip-flopped on the trans. fluid with the tsb going from 75w90 to the DCT stuff which is half the viscosity. Redline MTL 70w80 is a bit lighter than Motorcraft QS but heavier than the DCT fluid, the ease of shifting was noticed immediately from the 1st shift (the one most people complain about)

5 DOT 0

They do? The Torsen diff does not need friction modifier as confirmed by Ford and Torsen. I know the manual says to use it...

P0 Corsa

Good question Adam, I too wonder why "stuff people are changing to" is not the OE recommended Motorcraft fluids?

Anyone got data (not opinions please) which is convincing enough to support a switch to some other fluid manufacturer or viscosity for the rear axle and/or transmission lubrication?

zwede

I'm tempted to try RP Synchromax in the transmission. My previous car was a '05 BMW M3 that was very difficult to get into 2nd when cold. Even warmed up it was a hard shifting transmission. Replacing the factory fill with RP Synchromax made a dramatic difference on that car. I also run RP Synchromax in the Tremec TKO 5-speed I have in my '71 Corvette and love how nice it shifts.

The 6-speed in the Boss is fairly nice shifting but still wondering if RP synchromax would improve it further?

AlsCobra

Would like to know myself. It works well in my T56 but my trans is not built for smoothness or quiet any more.