gear oil woes.

[EricF]

Ok.. the dana 35 diffies in my 93 Ranger 4x4 with 221k, original everything...needs the gear oil changed. I used Valvoline conventional 80w90 and put the friction modifier in last time, which was oh.. a long time ago.

After reading and re-educating myself on gear oils and all the quirks of all of them.. i'm not sure if I should go with what I've been using, and.. since the truck was new, the gear oil's been changed in both axles, a total of 2 times.

should I keep the same formula & go with the conventional with friction modifier, or go with a semi synthetic with the friction modifier, or go with full synthetic, and skip the friction modifer? OR add it in as well, since it can't hurt anything?

 

[SuperDave456]

I recently did my Ford F-150. The manual says it has a "lifetime fill" of "Synthetic 75w140".

I didn't believe them. So I found a local Amsoil dealer and refilled it with the Amsoil Severe Gear 75w140 and added their Slip Lock just to be sure about things.
I don't do many heavy loads and the Amsoil stuff is supposed to last 100,000 miles. So I am good for a few more years.

Check your manual and see what it says. I recommend synthetics in differentials just cause it really can extend the service required of them.

 

[Zaedock]

No need to add friction modifier to an open diff. Use the 80W90 and you're good to go.

 

[Johnny]

If it has worked for 221K stick with what you're doing. If it ain't broke, don't fix it.

 

[DieselTech]

Originally Posted By: Johnny
If it has worked for 221K stick with what you're doing. If it ain't broke, don't fix it.


+1

 

[bluestream]

If you have changed it twice and are having no issues, I would continue with what you have been using in the past.

 

[unDummy]

By 221k miles, there is no LSD worth worrying about.

Any gear oil straight up is good enough. If for some reason you get a little rear-end chatter, then add a little LSD additive. Usually its not needed because most gear oils have the LSD additive already blended in.

I'd use a blend or full synthetic.

 

[exranger06]

First, only the front diff in your Ranger is a Dana 35. The rear is either a Ford 7.5" or a Ford 8.8", depending on which engine you have. I recommend you look at this link --> http://www.therangerstation.com/tech_library/Axles.html to see what rear axle you have, and if you have a limited slip. If you do not have a limited slip, you do not need any friciton modifier. Also, Rangers never came with limited slip in the front, so you definitely don't need modifier in the front axle. Any 90W oil, such as 80w-90 or 75w-90 will be fine.

 

[PT1]

Use Valvoline Durablend 80w90 which is 30% synthetic and has the LS additive already in it. If you get a copy of the AAP $10 coupon in the rebate threads (make sure it is the yellow one dated 12/31/09 you can save $10 before 12/31