Changing differential fluid - A step by step "HOW TO"

Picked Up 3QT Royal Purple

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 + Redline Additive @ 4oz

WISH ME LUCK !!

 

Oh boy!!! Ok here we go

Changed out the diff and Trans fluid here is what I used and my results

OEM Trans Fluid simple pan flush and fill

Royal Purple diff fluid
Redline additive

Chatter is a WORSE and now in more gears then just 4th going into 5th -

In the best way I can explain this is as if you're driving an manual transmission and you go from 1st to 4th by accident - that chatter that feeling you get the mild bumpy jerky feeling is what I get- keep in mind my truck is automatic, the chatter lasts a few seconds the car engages upshift and I'm good to go

My problem only occurs at low speeds and when driving aggressive there is no issue whatsoever -

Thinking it may be a sticky solenoid or maybe just my tranny going out - any ideas fellas !!??!??

 

Well the only thing I did do to the transmission was a pan flush and fill do you think I should do a complete pressurized flush the transmission and then try ?

Strangely enough if I drive in fourth gear again in my automatic but just slap the stick over to the left into fourth I never experience the problem . In regular drive mode I can feel that issue in other gears like second third and usually and most commonly 4th going into 5th. I'm stumped

 

Some rear diffs DO NOT like synthetic fluid others it does not bother. drain and fill with dino oil and see if it goes away

 

Thanks fellas will try this tomorrow !!

 

Where do I get DINO oil from? Does it have a brand or name I can search?
Is there weight to it? IN a quick google search its not very specific

 

So I changed my rear differential oil today, and had some questions and some comments

First off, the oil didn't seem bad at all after 22,000 miles. I know it's short, but some have said it was bad in the 25-30000 range. Plug didn't have much for gunk either. I only drained out about 2.5 quarts, don't know why it was low.

Two questions

1. When I loosened the fill, there was a slight release in pressure. Shouldn't the breather take care of that? I haven't put the rear in any water so I wouldn't expect it to be blocked

2. When refilling, it took a little over 3.5 quarts. Seems weird, truck was level. Anyone else have this amount go in?

 

I use lucas gear oil

 

Does this Lucas or "DINO" oil need 4oz additive as well? i.e. Valvoline

 

If it's a sport with the sticker, yes.

 

1. Stock breather is one-way. It will let pressure out when the diff heats up, but when it cools there will be neg. pressure. What you heard was likely vacuum release and not pressure release. You should consider a breather relocate with a 2way valve.

2. I got almost 4 in mine but I also tilted the axle each way to make sure I drained all I could.

 

Thanks man much appreciated, Yes its a real SPORT model , thank you again

 

HAHAHAHAHAHAHAHAH I THOUGHT I WROTE BABE THATS AMAZING ,
IM MULTI TASKING WITH MY WIFE IN THE KITCHEN HAHAAAAA

IM NOT GOING TO EDIT THAT NOWW HAHAAAAA

 

Yup you're prob right. Thanks!

 

I just changed both diffs and transfer case to Mobil 1 75w90. The diffs were dirty but nothing crazy or bad at 20000 miles. 5000 of those miles have been towing. I don't feel much of a difference just slightly smoother. It was much easier than I thought and the hand pump was well worth the 5 bucks. And it took almost exactly 6 quarts.

 

So I am about to do the rear, front, transfer case at 30K. Been buying supplies a little here and there, do I need crush washers for these or no? how many, 2 each, sizes?

 

I'm going to try AMSOIL when I change my diff oil, assuming I can get the drain plug and fill plug off. The first time I tried they wouldn't budge so I sprayed them with PB Blaster and bought a breaker bar for my ratchet. I'm kinda one the fence with the cost of synthetic visit dino as I plan on changing it every 25-30k.

 

My rear diff oil was either original or it was changed sometime before I got her at 42 k miles (unlikely). When I changed it at 137 k miles it was very clean. Almost like new oil.

However, I only dunked the rear once that I can remember.

My manual ONLY says to change it if you fall into the non-standard service schedule. The other schedule never says to change it, only check it. If I don't dunk the rear I'll probably wait at least 50 k miles before I change it again and yes, I used synthetic.

Transfer case and manual transmission oil were also ridiculously clean. Same history on those and same plan for future changes. I am doing the front diff Friday and I suspect it will be just as clean and if so I will wait 50 k for another change.

If I was dunking it a lot I would go with dinosaur oil and change it more often.

 

Finally did my front diff. 10 mm hollow hex head for both plugs. Old oil was just as clean as the rear diff. Torqued plugs per the TFSM as follows:

Drain plug: 48 lb-ft
Filler plug: 29 lb-ft

48 lb-ft sounds like a lot but I had actually already hand-tightened it beyond that with a ratchet. I had to back it off.