Another Gear Oil Question

[Cyprs]

I am going to change out all dif, tranfer case, manual tranny gear oil in my 86 4X4 Toyota, also the dif gear oil in my 92 dodge diesel when I do the brakes on this floating axle.

The diesel will pull a 4000 lb trailer and it does get +90F or +37C here and -40F/C in winter. (I do have 85-140 in there now as I do get a good hop in dif in winter when extremely cold.)

Can I use 80-90 gear oil in this Dodge Cummins dif year round or should I stay at 85-140?

Will 80-90 be a good choice for all gear boxes in Toyota too?

thanks again
cyprs

 

[rslifkin]

For the Dodge, with the loads it sees, and the torque of that engine, sticking with an xxW-140 is probably a good idea for the additional protection. I'd go with a 75W-140 synthetic for better cold weather properties, personally.

For the Toyota, either 75W-90 (comes in synthetic if desired) or 80W-90 should be fine in the diffs. I don't know enough about that vehicle's t-case and tranny to make a recommendation for those.

 

[salesrep]

80-90 year round in both of these will work fine.

 

[Cyprs]

SR, 80-90 is what my local Dodge Dealership recommend for the the Dodge Cummins dif.

On other hand that dif sees a lot of hot weather loads, RS I think the syn option with higher weight may be the way to go because then I would not face changing weights on oil seasonally, probably save money on syn in long run.

Another option comes to mind: Can gear oil weights be blended like HDEO as long as one stays in same brand and application? My dodge dif capacity is about 3 litres/quarts, can I go 2 litres 80-90 and 1 litre 85-140 for a comprimise for all year round dif heat protections and cold flow?

thanks,
Cyprs

 

[river_rat]

Originally Posted By: Cyprs
Will 80-90 be a good choice for all gear boxes in Toyota too?

thanks again
cyprs


I would go with Amsoil Severe Gear 75W-90 in the 'yota considering the temp extremes. Second choice would be Valvoline synthetic in same weight, unless you need a GL-4 only rating in the tranny. Then StaLube 80W-90 for the tranny only. Just a suggestion.

 

[Cyprs]

thanks r-r,
Cyprs

 

[river_rat]

You will like the way she shifts.

 

[Jim Allen]

I think a 90 grade would be fine for both truck's axles, based on my monitoring of axle gear oil temps on several trucks over a few years. A 4000# load is nuthin' for the Dodge (D70 rear axle) even with 90F factored in.

The Toy definitely is fine with a 90 grade. If you went mineral, then 80W90 is your choice (for both trucks). A 75W90 syn would cover you better in the low temp extreme on both trucks.

As for trannies/t-case, I would follow the mfrs. recommendation on base viscosity and API class (GL-5/GL-5). A 75W90 usually works well too, if the API classification lines up.

In case you didn't get the hint, I'm more concerned with using a name branded oil of the right classification and viscosity than I am of what name is on the bottle. The differences in service between the off-the-shelfs are not gigantic IMO. You could say the same thing about the premium boutique oils... not always a whole lot to choose between them, so let you wallet be your guide.

 

[Cyprs]

thanks Jim, will get a bottle of "limited slip" for the Dodge for good measure, I will pick one of choices of weights shown above in conventional or syn offered here, will hit the shelves and see the damage on pricing, syn oil would be good for my temp extremes by look of it.

thanks all again,
Cyprs

 

[Rob_Roy]

I would run a quality 80w90 or 75w90 in everything.

4k lbs is peanuts for the axle in that Dodge. Our '93 Dodge 1-ton w/ Cummins had over 200,000 miles with 80w90 when we sold it; over half the mileage was towing 12k+.