Engine/Transmission (1994 - 1998) Mineral base/synthetic

[AWallace]

My 95 has 96k on it and I have always used Valvoline 80-90 mineral base gear lube in the diff. with no problems. What are the chances of gaining a bunch of leaks if I go to a full synthetic 75-140. I change about every 40 to 50k. sometimes less mileage. Also what is the torque on the bolts I forgot already.

 

[AWallace]

I forgot one other thing do you have to use a additive with the synthetic.

 

[SRath]

My experience with synthetics in general has been pretty much limited to Mobil 1 and Amsoil.

My biggest complaint about Mobil 1 (or Delvac 1) is how badly it leaks from anything you use it in.

After switching to Amsoil, I saw a huge decrease in oil leaks from engines and diffs.

Amsoil gear lube claims to be fine for Limited slips just as it comes out of the bottle. However, if you experience clutch chatter from your limited slip for some reason, Amsoil does sell a compatible additive.

 

[fest3er]

The logical explanation for leaks after changing lube is that the new lube has dissolved deposits that built up on the seals. In other words, the seals would have leaked if the deposits hadn't been there, regardless of which lube you used. This is most true with regard to engine lube where combustion acids can react with oil and other stuff in the oil to cause sludge which can then build up inside the engine; Amsoil is usually blamed for causing these leaks when it's just doing its job: neutralizing acids and dissolving sludge which results in failed seals leaking.

I'm confident you can switch to a top quality synthetic gear lube and not worry about seals leaking unless those seals are already at or beyond the point of failure. If you've never resealed the axles, now might be a good time to do so. Seals don't least forever, especially baby seals in Canada. But I digress.

 

[HLEschenko]

I've been using amzoil 75-90 for over 200K. I did try the amzoil without the additive and the LSD clutches were seriously galled. The debris was ground up by the gears and finally went into the bearings resulting in oil leakage from the pinion seal. All bearings were damaged by the very fine metal particles. I would not use any lubricate without the additive.



The LSD clutches are coated with a very thin layer of some kind of plastic, teflon, or polymer. Never researched it. Once that layer is removed, it's metal to metal contact. Not good! My $0. 02.

 

[SRath]

The old-style PowerLok clutches were solid steel. No coating. And they worked MUCH better and lasted longer.

Amsoil has never caused any leakage problems on anything I used it on. In fact, when I replaced the Mobil 1 I had used for years with Amsoil, the leaks stopped, so I don't think it was a matter of dissolving dirt, either. Mobil 1 is just hard to seal.

 

[Missouri Mule]

I switched to Amsoil 75w140 in my diffs after 100,000 mlies no leaks. (reg rear end)

 

[JMcCoy]

I currently run Mobile 1 front and back. My LS diff chattered until I put in one tube of additive. I have been planning to change to Amsoil, but no one sells it around here. I just don't have to foresight to order it, before I get the spontainious urge to change it. One day I suppose. Good luck

 

[SRath]

I have no complaints about Mobil 1/Delvac 1 synthetics' lubricating properties, I just can't stop it from leaking past seals. In cars, trucks, or motorcycles.

 

[JMcCoy]

Everything I have Mobil 1 in leaks. Maybe you have found the common denominator. Of course, since it is my truck that I have had since new, does that consider ME a common denominator? Doesn't sound good for me.

 

[rluft]

I run amsoil with the additive. The LSD will chatter without the additive, my experience.

 

[fest3er]

I run amsoil with the additive. The LSD will chatter without the additive, my experience.

It will. It can. It may. Any one will be true, depending on how a diff's clutch packs have been assembled.

When I first switched to Amsoil around 90K miles, I never added any modifier. The rear clutches chattered some. In time, the chatter mostly went away. After a lube change or two, I never experienced much more than a slight vibration in a slow, sharp turn.

But then I stopped driving so much. In the past couple years, I'll often fill the tank only once every month or two. On this past Friday, before heading to MDTDC's Spring Fling about 260 miles north, turning a moderate corner not so slowly was giving me very noticeable, strong, and disconcerting chatter. After returning, I've now noticed that the chatter is gone.

It takes time for new lube to replace the previous lube in the clutch packs. And if the vehicle isn't driven much, the clutch packs can 'dry out' (maybe the pressure squeezes the lube out?) and it will take time for lube to work its way back in.

 

[CTD12V]

I too need to change my rear diff oil. If I change just the fluid now, can the axle seals and pinion seal be changed out later (if they start leaking) without losing a bunch of fluid, or is draining the gear oil necessary to replace any of the seals (other than the diff cover, obviously)?



Thanks,



CTD12V

 

[fest3er]

I too need to change my rear diff oil. If I change just the fluid now, can the axle seals and pinion seal be changed out later (if they start leaking) without losing a bunch of fluid, or is draining the gear oil necessary to replace any of the seals (other than the diff cover, obviously)?



Thanks,



CTD12V

If you have too much fluid in the diff, it can drain out the axle tubes. Normally though, you can change the axle and pinion seals without draining the diff (as long as the axle is fairly horizontal). At worst, a tiny amount might drain out.

 

[CTD12V]

Thanks for the info. That's kind of what I thought, but wasn't sure. I guess I could always jack up the side I was working on if there was enough oil keeping me from getting a dry seal install.

 

[GAmes]

I recently had my pinion seal replaced. The shop had jacked up the rear of the truck. 4 quarts of my $17 a qt Royal Purple drained out. With the mag-hytec cover it holds 7. The mechanic told me he thought a qt, maybe two had drained out so I drove it 70 miles home and bought a couple qts on the way. After getting home I checked the dipstick and there wasn't any oil on it at all Back to the auto parts (with a different vehicle) and bought 3 more qts. It took four to get the oil to drain out the center hole. I'm still sweating if there was any damage done after 2500 miles of driving.

 

[CTD12V]

Yikes!

 

[BigEasy]

Mobil1 leaks because they don't use 'seal swellers' in their formula... if you swap out the Mobil1 for another quality oil, the leaks will stop. I prefer products from Schaeffer's or Lubrication Engineers.

 

[SRath]

Yup. I did. They did. Amsoil for me, though their prices are getting downright offensive anymore.