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Rear Diff oil blues....

135K views 232 replies 93 participants last post by  Mike Murrell 
#1 ·




Ok, after reading about all you guys changing your gear / differential oil to synthetics such as Royal Purple, Redline, etc., I decided to take the plunge.

My first struggle was figuring out if my rear diff was limited slip or not; after talking with a mechanic at the Toyota dealer he told me it was NOT limited slip because it has a rear diff lock function.

The first problem is that my local parts stores only seem to carry Royal Purple Gear oil (75-90) gear oil that is FOR limited slip differentials, so I ruled this type out.

I found Redline gear oil at another store and the guy there assured me it would work in my non-limited-slip diff, but then the bottle states “Highest performance in limited-slip differentials” and then later it states “Contains additives for limited-slip differentials”.

All other specifications on the oil match the factory recommend gear oil specs.

So, will this oil work? Is Redline the way to go or should I try and find a Royal Purple or Mobil One that will work?:confused:

Thanks for the feedback.

 
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#28 ·
Ok, so thanks to a lot of the feedback I’ve received in this forum, I too have bit the bullet and changed my gear box (front diff, transfer, rear diff) oil to synthetic. I’ve used Redline 75W90. The truck seems to be running really smooth now, but I’m not sure if I can attribute it to the oil change. Here are a couple of things I ran into:

  • The Royal Purple and Redline oil both say they are for limited slip differentials. My first problem was to determine which type of rear diff my Taco actually has. I called the dealer and they couldn’t decide, so I stopped in and actually spoke to a mechanic who came out and checked and he confirmed that my truck does NOT have a limited slip rear differential. It seems that trucks with the rear locking differential always have the non-limited-slip configuration.

  • Since the 75W90 Redline Oil says that it works in both types, so I called tech support at the Redline Company and an engineer confirmed that the limited slip additive would not harm a normal gear box.

  • I also purchased all new gaskets (6 total) for this job; it only took the parts guy at the dealer about a half hour to look up all the part numbers, but he finally had it all together and they all worked.

  • Heads up on the front differential: you will need a 10mm allen head driver/wrench for the drain & fill caps. That is after you remove the protective cover bolted onto the underside of the truck.

  • Just as others have reported, my oil coming out of both differentials looked nasty, but the transfer case oil was pristine. Both differentials have a magnet in the drain plug and both had quite a bit of shavings and gunk built up. I’m glad I decided to do this procedure rather than waiting…

  • If you haven’t done this job yet, note that you will absolutely have to purchase a small hand oil pump. I picked one up for about $4 at the auto-parts store where I purchased the oil.

My truck has just over 7k miles now, so this should last awhile. I’m curious to see if I will actually notice an mpg improvement.:thumbup:
 
#30 ·
PDX- any chance you have the PN's handy from your invoice?

pdx said:
Ok, so thanks to a lot of the feedback I’ve received in this forum, I too have bit the bullet and changed my gear box (front diff, transfer, rear diff) oil to synthetic. I’ve used Redline 75W90. The truck seems to be running really smooth now, but I’m not sure if I can attribute it to the oil change. Here are a couple of things I ran into:

  • I also purchased all new gaskets (6 total) for this job; it only took the parts guy at the dealer about a half hour to look up all the part numbers, but he finally had it all together and they all worked.
 
#31 ·
What size or type of wrench to remove the rear differential plugs?

Hi all

I have the type of limited slip system that comes from the brakes being applied to the wheel that is spinning. I am assuming that I do not need LSD specific oil for this job.

What size and type of wrench will I need to remove the drain plugs?

2005 Prerunner access cab 4 cyl manual Sr5.

Thanks!
 
#32 ·
Metric allen wrenches but I dont remember the specific size. If you have a set of metric allenhead wrenches youll be able to figure it out.
 
#33 · (Edited)
Just changed the fluids in my rear diff, x-fer case, and front diff. I used the Redline 75W90 for LSD's all three. Here's my summary for each:

Rear Diff- a PITA to take off the bolts. Might have had to do with the fact that I tried this right after driving the truck. I came back to this last and the bolts FINALLY came undone. Fluid that came out wasn't as dirty as the front diff.

X-Fer Case- cleanest off all the oils that came out. Looked and smelled brand new. Oh well. Its done.

Front Diff- also a PITA to take off the bolts. Ended up using my feet for leverage to loosen. :) This stuff was all dark and nasty. Dirtier than the rear diff:eek:


Here's the breakdown of PN's for the gaskets:

Rear Diff: 2x 12157-10010
X-Fer Case: 2x 90430-18008
Front Diff: 1x 90430-24003 (big copper one for drain); 1x 12157-10010 (same as both for rear diff)

Here's the fluid capacities for each: (from dealer guide- I watched the guy look these up)
Rear Diff: 3.0 qts.
X-Fer Case: 1.1 wts.
Front Diff 1.6 qts.
(Filled each till the fluid just started to run out the fill holes)

Truck just past 20K miles...10 months new....:clap:





pdx said:
Ok, so thanks to a lot of the feedback I’ve received in this forum, I too have bit the bullet and changed my gear box (front diff, transfer, rear diff) oil to synthetic. I’ve used Redline 75W90. The truck seems to be running really smooth now, but I’m not sure if I can attribute it to the oil change. Here are a couple of things I ran into:
  • The Royal Purple and Redline oil both say they are for limited slip differentials. My first problem was to determine which type of rear diff my Taco actually has. I called the dealer and they couldn’t decide, so I stopped in and actually spoke to a mechanic who came out and checked and he confirmed that my truck does NOT have a limited slip rear differential. It seems that trucks with the rear locking differential always have the non-limited-slip configuration.
  • Since the 75W90 Redline Oil says that it works in both types, so I called tech support at the Redline Company and an engineer confirmed that the limited slip additive would not harm a normal gear box.
  • I also purchased all new gaskets (6 total) for this job; it only took the parts guy at the dealer about a half hour to look up all the part numbers, but he finally had it all together and they all worked.
  • Heads up on the front differential: you will need a 10mm allen head driver/wrench for the drain & fill caps. That is after you remove the protective cover bolted onto the underside of the truck.
  • Just as others have reported, my oil coming out of both differentials looked nasty, but the transfer case oil was pristine. Both differentials have a magnet in the drain plug and both had quite a bit of shavings and gunk built up. I’m glad I decided to do this procedure rather than waiting…
  • If you haven’t done this job yet, note that you will absolutely have to purchase a small hand oil pump. I picked one up for about $4 at the auto-parts store where I purchased the oil.
My truck has just over 7k miles now, so this should last awhile. I’m curious to see if I will actually notice an mpg improvement.:thumbup:
 
#35 · (Edited)
3 are actually the "crush washers", while 3 are regular washers...we are referring to them all as "gaskets" as that is what the item description Toyota uses on the parts invoices.




qjonny said:
Do you all mean the crush washers, when you state "gaskets"? I don't see why you'd need gaskets to simply un-screw the drian plug.
thanks
06 4x4 V6 X-cess Sport TO
 
#36 ·
Thanks

TacoSport05 said:
3 are actually the "crush washers", while 3 are regular washers...we are referring to them all as "gaskets" as that is what the item description Toyota uses on the parts invoices.
Thanks, that's what I thought. But I wanted to be sure, cuz I thought maybe some guys were taking the whole Diff case/pan off to drain.LOL
 
#37 · (Edited by Moderator)
Changing Front and Rear Diffs and Xfer case-2005+ Tacoma (with pics)

I had been planning to put a detailed "how to" together on the front and rear diff and transfer case maintenance, and finally got around to finishing it up. There have been other posts containing bits and pieces of this information, but now hopefully this detailed step by step with pics pulls all of that together and will help some guys that are hesitant to give this a crack.

The rear diff is easier than an oil change. The front is only more difficult because of its location.

Added the transfer case write up with pics down below.

Materials:
- 6 quarts of 90 weight gear oil (I used Redline 75w-90ns for my TRD Off Road with Locker) for both diffs and the transfer case, or
3.0 quarts for rear diff
1.6 quarts for front diff
1.1 quarts for transfer case
- TRD Sport models and trucks with the mechanical LSD should use Redline 75w-90 (not the ns), as this contains the friction modifiers necessary for the LSD. If you are using a different fluid brand, just make sure it is formulated for LSD rear ends.
- 2 Crush washers for rear drain and fill plug
Part No:12157-10010 x 2
- 2 Crush washers for front drain and fill (larger copper washer is for front fill)
Part No: 12157-10010 x 1 and 90430-24003 (copper) x 1
-2 crush washers for transfer case drain and fill plug
Part no: 90430-18008 x 2 (05Moose: Latest part number is 90430-A0003)
- 10mm hex head socket for front drain and fill plugs
- 24mm socket for rear drain and fill plugs and transfer case plugs
- Torque wrench to tighten plugs to spec.
- 12mm socket (with 3” extension) to remove lower skid plate (not shown)
- Oil hand pump (shown later in action)
- Optional: Jack, Rubber mallet

This picture is for the front and rear diffs. Add another quart of oil and 2 more washers for the transfer case.



To get your truck ready for the fluid change, drive it around and get the engine warm and the gears moving. Return to your garage, and let the truck cool for about 15 minutes.


REAR DIFF
Loosen and remove the fill plug first using a 24mm socket (you don’t want to drain the old fluid out and then figure out the fill plug is stuck)



Then loosen and slowly remove the drain plug with the same 24mm socket, and let the old fluid drain into an oil pan.




I let it drain for a good 15-20 minutes. I also got my floor jack out and lifted the left side of the truck to help the draining process.
After you are satisfied with the draining, apply your new crush washer to the drain plug. Add a bit of oil to the threads, and hand screw the drain plug into the diff to ensure that you don’t cross thread. Screw it in until snug.
Then take your torque wrench, and torque the bolt to 36 ft lbs.


Now you are ready to add the new fluid. You’ll need a hand pump to make life easier. Just attach the base of the pump to the fluid bottle, and the hose to the fill plug of your diff, and start pumping. I had no trouble getting 3 qts into my diff, but you’ll want to watch for the fluid to start seeping out of the fill hole.




Once the fluid starts seeping out of the fill hole, stop pumping, and apply the fill plug with it’s new washer. Screw it down hand-tight. Get all of your stuff out of the way, and take the truck for a spin around the block. When you get back, remove the fill plug, and pump in more fluid until it starts seeping out again. I was able to add about .1 - .2 qt more.
Plug the fill hole, wipe away the excess fluid, and torque the bolt to 36 ft lbs. You’re done!


FRONT DIFF
Start by removing the lower skid plate. There are four 12 mm bolts that hold it in place. The front two bolts are set into the plate a few inches. I used a 3” extension to get them out.
Sorry about all the mud; still cleaning up from my muddy hill climb a few weeks ago. If you’ve been mudding in your truck, I advise you to pull the skid plate and clean up behind it. There was tons of mud behind the plate.
Looking from behind the front left wheel toward the front of the truck, here’s what you see. Two bolts are shown; the other 2 are a mirror image on the right side.






Pay attention to the tabs in the skid plate that rest on the frame to help support it. There are 2 up front, and one in the right rear. You'll want to make sure you put it back like this when you're all done.
Once the skid plate is out of the way, there’s a clear view of the front diff from behind the left front tire. It’s cramped in there, so you could consider jacking the truck up to create more space to loosen the bolts, but be sure to lower it back to the ground before removing the drain plug so that you get proper drainage.




Again, remove the fill plug first using a 10mm hex head socket. Mine required a couple taps to the socket wrench with a rubber mallet to break the bolts fee. Once the fill plug is out, remove the drain plug with the same 10mm hex head socket.
Set the bolts aside, and let the fluid drain out. This time I jacked up the right side of the truck to get as much old fluid out as possible.



Once the fluid has drained, apply the new copper washer to your drain plug, and hand screw the bolt into the diff housing until snug. Then use your torque wrench and tighten to 29 ft lbs.


Follow the same process for adding new fluid to the front diff. Use your hand pump, and pump in about 1.5 qts into the fill hole, or until fluid begins to seep out of the fill hole. Apply your new crush washer to the fill plug, and hand screw it until snug.
Get your stuff out of the way, and take it for a spin around the block, allowing the oil to warm a bit and settle. Once back in the garage, remove the fill bolt and pump in more fluid until it begins to seep out the fill hole (I got about .2 qts more in). Hand screw the fill plug back in until snug, wipe away the excess, and then torque it to 29 ft lbs.


Finish the job by replacing the lower skid plate. Be sure to align the notches on the front end of the plate so they rest on top of the cross member, and the notch on the rear right of the skid plate into the hole just to the left of the right rear bolt. Once you get these notches in place, the skid plate will rest in place so that you can screw the four bolts back in. I just wrenched them down hand tight.

TRANSFER CASE

Transfer case takes a little more than 1 quart of oil (approx. 1.1 qts). I used 25 ft lbs for the torque spec for both the drain and fill bolts.

Loosen and remove the fill plug first using a 24mm hex bolt socket. Some fluid may seep out of the fill bolt when you remove it – this is Ok.



Loosen and slowly remove the drain plug next using the same 24mm socket. Be careful! Fluid may squirt out with some amount of pressure, so be ready with your catch pan. As the fluid drains, you’ll need to slide your catch pan closer to the transfer case as it begins to trickle out.



Give it a good 10-15 minutes to drain as much of the old fluid as possible. If you like, you can jack up the front end of the truck to help the draining process.

Once you are down to a slow drip, slide the new crush washer over the drain plug, and screw it back into the case. Apply 25 ft lbs of torque and tighten the bolt.

To apply the new fluid, follow the same process you used for the diffs. Apply the base of your hand pump to the new bottle of fluid, and the hose end into the fill plug of your transfer case. Start pumping, and add 1+ quarts of the new gear oil.



You’ll know it is full when gear oil begins to seep out of the fill plug hole. Once this happens, remove the pump hose from your transfer case, and screw the fill plug (with new crush washer) into the case until hand tight. Clean up the fluid drips on your case, and using the torque wrench, tighten the bolt to 25 ft lbs. (You can optionally screw the bolt hand tight, drive around for a few minutes and engage the transfer case, and then return and top off the fluid before torque’ing the fill bolt.).

That’s it! Start the truck, check for leaks, and check for leaks again in 24 hours.
Hopefully this detailed write up and pics will help someone trying this out for the first time.
 
#45 ·
rneily said:
Anyone done the flud change and bought the 4 washers for the front and rear diffs? I went today to the dealership and was surprised that the four washers were over $8!
Seems a bit high, but unless you bargain with them, expect to get a huge markup on those things. I paid about $1 each for the rear diff washers, and $2 each for the copper washer.
 
#46 ·
AfterShock said:
They do use aluminum crush washers. I have been re-using mine. As long as you torque the bolt correctly and check for leaks a few days after you should be good to go. I personally haven't had any leaking problems but if you want peace of mind then go spend the .50 cents on the washer :)
The dealership tried charging me $4 per washer

He almost could'nt keep a straight face while I laughed at him

I ended up still paying $2 for each
 
#47 ·
Muddskipper said:
The dealership tried charging me $4 per washer

He almost could'nt keep a straight face while I laughed at him

I ended up still paying $2 for each
:disappoin Don't you wonder how many folks continue to pay "dealer retail" for parts? There's always room to negotiate, especially for washers and small parts that they have volumes of in their shop. Even $2 sorta feels like you got raped a bit though, doesn't it?
 
#49 ·
i went out today and got all the supples needed for this and i get home and couldnt get the stinkin fill plug off in the rear! i tried everything i could think of tapped the head of theplug with and without the socket on, used rust penetrate and tapped it. i didnt wanna use an impact wrench though because i didnt wanna strip the head off so any suggestions or is there a trick that i dont know about?
 
#50 ·
06RadiantTacoma said:
i went out today and got all the supples needed for this and i get home and couldnt get the stinkin fill plug off in the rear! i tried everything i could think of tapped the head of theplug with and without the socket on, used rust penetrate and tapped it. i didnt wanna use an impact wrench though because i didnt wanna strip the head off so any suggestions or is there a trick that i dont know about?
I've had great luck with PB Penetrating Catalyst on frozen/rusted bolts, etc. I have to admit, though, I haven't had the exact same situation you've had.

Andy
 
#51 ·
Screeber, ty for the awsome write up!!
Mudskipper, sounds like they tried to use 36 grit vasaline on you :eek:
I got 17k on my beast and will be changing out the f/r diff oils this weekend. I got LSD, (WOOOOOOW man). If they try to use the 36 grit on me, I'll whip out my 400 grit and try fight to get them for the $1.89 that Buell did. Luckily, I know someone who works for a Yota dealership in the parts dept. but it's a 90 min round trip and it's in a nasty traffic location, so, I'll try the local dealer first
 
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