What weight fluid in differentials?! ---

[alwayscode390]

I was told to try ROYAL PURPLE fluid in my differential.....what weight should I go with? I searched and even checked my POS chiltons and it just says " use weight specified " , I was like WTF. Should I go synthetic? I am about to put on my TA girdle with bearing supports, so I shouldnt be back in there for awhile. Thanks ---

 

[Black Knight]

Re: What weight fluid in differentials?! ---

I wouldnt waste my time with Royal Purple in your diff.'s, I wouldnt use synthetic either there is no need for the price, just go get standard 90 weight at the parts store, I use 85W-140, but thats me.
This is all IMO so im sure someone wont agree with me and tell you, you have to use Royal Purple or you have to use Synthetic, I just say BS. Do as you will the stuff wont hurt anything though, well your wallet.

 

[Beavis]

Re: What weight fluid in differentials?! ---

I used Royal Purple in mine (front and rear) and it SEEMED to roll a little smoother. It could just be the drugs thought. I have no complaints with it, and if I remember right, it wasn't THAT much more $$$. Just my :2cents:

 

[alwayscode390]

Re: What weight fluid in differentials?! ---

Awesome, 90 weight it is , thanks guys ---

 

[big gear head]

Re: What weight fluid in differentials?! ---

I've been using Amsoil 75W90 synthetic in them for about 10 years. Amsoil is a little harder to find, but I think it is the best. Just my opinion, take it or leave it.

 

[alwayscode390]

Re: What weight fluid in differentials?! ---

Amsoil IS the best, but dont you have to get it from a supplier? I am not doing the diff. in a hurry....so that may be a good idea to order some, thanks!!! ---

 

[James Thomas]

Re: What weight fluid in differentials?! ---

On the topic of synthetic lubes, I will go out on a limb here but it does make a difference. Don't let anyone tell you different because the tests PROVE IT. I personally like Red Line but any full 100% (not the blends!) synthetic from a quaility proven Mfg. like Royal, Red Line, Amsoil, Torco etc. will be better than a petro based lube. We use it every where including greases and Hyd. Fluids in the the industrial line. The only thing I am not sure of is tranny fluid and I plan on trying it on the next one I have built but George Blake can most likley chime in here on that.
____________________
James Thomas

 

[George Blake]

Re: What weight fluid in differentials?! ---

Don't use synthetic fluid of any kind in an automatic transmission that specifies DexronII, IIE, or III. It does two things. It softens the rubber seals and makes them break down and it can actually dissolve clutch material. Use a name brand regular fluid, run a cooler, external filter and change it every 10K and you'll have NO problems.

 

[dgoodhue]

Re: What weight fluid in differentials?! ---

I use redline synthetic all through my truck except the transmission. In magazine and independent dyno tests, I have seen small gains 5hp-10hp from using all Synthetic in the driveline. I used 75/90 in the F&R ends and ATF in the T-Case.

 

[George Blake]

Re: What weight fluid in differentials?! ---

Thought I'd add something. MANY years ago, a couple members found out that using synthetic grease mixed with standard grease resulted in a strange "hardening" process. The place where it was used was on the bearings at the ends of the half shafts when seals were replaced. Within 100 miles, smoke was coming out of the wheels and upon inspection the grease had turned into a hard road tar like substance. Just FYI since we were talking about synthetics.

 

[SyTyJedi]

Re: What weight fluid in differentials?! ---

I have always used RedLine Shockproof gear oil in the diffs and Amsoil High Temp ATF w/Lubegard in the trans.

No complaints. Also noticed reduced driveline noise and the truck seemed to 'free wheel' easier when i let off of the gas, as in there was less friction slowing it down.

 

[James Thomas]

Re: What weight fluid in differentials?! ---

Don't use synthetic fluid of any kind in an automatic transmission that specifies DexronII, IIE, or III. It does two things. It softens the rubber seals and makes them break down and it can actually dissolve clutch material. Use a name brand regular fluid, run a cooler, external filter and change it every 10K and you'll have NO problems.

Hey George, GOOD INFO on both of your posts! I forgot to mention the grease incompatibility between most synthetic grease and petro based. I normally just assume that most gearheads would remove the old grease / contaminants and clean a bearing housing or joint before "repacking" or at least "flush" anyway because you should!
BTW, many of the different grease types can react if mixed, synthetic or not. Always use the proper grease for the job and really make it a point not to "mix" unknows if it can be avoided.
______________
James Thomas

 

[AmericanMotorOil.com]

Re: What weight fluid in differentials?! ---

Use, AMSOIL - Severe Gear SAE 75-90 or Severe Gear SAE 75W-140 Synthetic Gear Oil in your Differentials and use AMSOIL Supper Shift non-slip racing Transmission Fluid in your Transmission.

Use AMSOIL - 5w-30 High Performance Motor oil or 10w-30 Turbo Formulated Motor oil in your engine.

I will be happy to talk to any of you regarding the AMSOIL product. It is the first synthetic motor oil ever and is still the best on the market.

Amsoil exceeds all petroleum products and other synthetic oil on the market. You can go to this website for further information: www.AmericanMotorOil.com

 

[Black Knight]

Re: What weight fluid in differentials?! ---

Use, AMSOIL - Severe Gear SAE 75-90 or Severe Gear SAE 75W-140 Synthetic Gear Oil in your Differentials and use AMSOIL Supper Shift non-slip racing Transmission Fluid in your Transmission.

Use AMSOIL - 5w-30 High Performance Motor oil or 10w-30 Turbo Formulated Motor oil in your engine.

I will be happy to talk to any of you regarding the AMSOIL product. It is the first synthetic motor oil ever and is still the best on the market.

Amsoil exceeds all petroleum products and other synthetic oil on the market. You can go to this website for further information: www.AmericanMotorOil.com

So your saying the lubricants that they recommend from the factory are not satisfactory??

 

[AmericanMotorOil.com]

Re: What weight fluid in differentials?! ---

:tup:

So your saying the lubricants that they recommend from the factory are not satisfactory??

I am not saying that what they recommond are not satisfactory, they are just not the best product. If you are satisfied with what you are getting from what they recommend then stay with it. But, if you want an edge over someone else with more performance from your vehicle then use AMSOIL.

 

[vinnieTy]

Re: What weight fluid in differentials?! ---

I went with Amsoil in the read end, front differential and transfer cause. Exact weight was what the site recommend and i have no problem at all. I have read alot on red line, amsoil and a bunch of other synthetic oils and i was happy with AMsoil from what i read and have no regrets after using it.

 

[AmericanMotorOil.com]

Re: What weight fluid in differentials?! ---

I went with Amsoil in the read end, front differential and transfer cause. Exact weight was what the site recommend and i have no problem at all. I have read alot on red line, amsoil and a bunch of other synthetic oils and i was happy with AMsoil from what i read and have no regrets after using it.

Hey, thanks for using AMSOIL. It is a product I firmly believe in. Not because I sell it, because I use it everything I own.

Do you have the AMSOIL Super Shift Transmission fluid (ATR-01) in your truck? If not, you would not regret it. :tup: :tup:

Amsoil High Performance Motor Oil 5w-30 (ASL-01) or Amsoil Turbo Formulated Motor Oil 10w-30. (ATM-01) :tup:

Check out the following link for information or contact me. I will be happy help anyone with product applications.

www.AmericanMotorOil.com

 

[SacDoug]

Re: What weight fluid in differentials?! ---

Thought I'd add something. MANY years ago, a couple members found out that using synthetic grease mixed with standard grease resulted in a strange "hardening" process. The place where it was used was on the bearings at the ends of the half shafts when seals were replaced. Within 100 miles, smoke was coming out of the wheels and upon inspection the grease had turned into a hard road tar like substance. Just FYI since we were talking about synthetics.

I had a tube of Mobil 1 synthetic grease in my grease gun for a year. There was red fluid constantly oozing out of my grease gun. I pulled out my grease gun last month to use and no grease would come out. I opened it up and all the grease was hard and packed tight like wax. I am not going to ever use Mobil 1 syntheic grease again. I might give graphite grease a try though.

 

[HotRudyRod]

Re: What weight fluid in differentials?! ---

Great info, i was just thinking about it and found this post. Any idea how much would i be looking to spend to replace the fluids on both differentials, TC and tranny? Thanks

Hey, thanks for using AMSOIL. It is a product I firmly believe in. Not because I sell it, because I use it everything I own.

Do you have the AMSOIL Super Shift Transmission fluid (ATR-01) in your truck? If not, you would not regret it. :tup: :tup:

Amsoil High Performance Motor Oil 5w-30 (ASL-01) or Amsoil Turbo Formulated Motor Oil 10w-30. (ATM-01) :tup:

Check out the following link for information or contact me. I will be happy help anyone with product applications.

www.AmericanMotorOil.com

 

[AmericanMotorOil.com]

Re: What weight fluid in differentials?! ---

Great info, i was just thinking about it and found this post. Any idea how much would i be looking to spend to replace the fluids on both differentials, TC and tranny? Thanks

Hey, thanks for your reply!! It would be to your advantage to become a perferred customer or dealer, you will get at wholesale cost that will be at 20 % discount. I will post a rough estimate for what you are asking.

Front axle - Amsoil - Severe Gear 75w-80 - 2 quarts
Rear axle - Amsoil - Severe Gear 75w-80 - 3 quarts
+ 1 extra = 6 quarts @ $64.80


Transfer Case - Amsoil - Torque-Drive Synthetic Transmission Fluid - 2 quarts
1 Gallon container = $36.75


Transmission filter - 58897 = $18.35
1 case of SuperShift Non-slip Racing Transmission Fluid = $102.60
**The extra transmission fluid is to flush the torque converter**

You can purchase Amsoil products or contact me by phone or email me at www.americanmotoroil.com

1991 GMC TRUCKS SYCLONE 4.3L 6-cyl VIN Code Z Turbo

BOSCH SPARK PLUGS
All submodels
Plug......NA

FILTERS
Oil Filter......EaO23/SDF23
Air Filter......EaA04
Fuel Filter......33481
Trans......58897


LUBRICANTS & FLUIDS
Engine Oil
Grade 1......API*[1]
Series 2000 Synthetic 0W-30 Motor Oil
SAE 10W-30 Synthetic Motor Oil
SAE 10W-30 XL Synthetic Motor Oil
All Temps......10W-30
Automatic Transmission.....AF3
Synthetic Automatic Transmission Fluid
Torque-Drive™ Synthetic Automatic Transmission Fluid (ATD)
Standard Differential, .....GL-5