Mobil 1 75w90 OK for older Tacoma?

Hello,

I'm picking up a 96 Tacoma 4x4 5spd 2.7l with 93k miles on tonight. I want to give the truck a good tuneup, including draining and refilling the front/rear diff, t-case, and manual tranny fluid.

I'm just wondering if running a synthetic such as Mobil 1 in all of these components would give me any negative effects, considering the age of the truck? I'd hate to mess the truck up considering the age of it. The synthetic isn't cheap either, but I'm hoping if it gives better protection, and helps with gas mileage than it'll be worth it.

Thank you in advance.

 

I don't think changing over to synthetic oil will hurt anything, but I would run the recommended oil weight and viscosity for that motor. It was design for a specific type of oil and changing that could lead to negative things. Just my $0.02 worth.

Good luck

 

I changed all my oils & gear lubes to mobil 1 at the first service and changed gear lube again at 100,000. at 144,000 now and everything still shifts easy and runs quiet, with no signs of wear.

 

I run Mobil 1 High Mileage 10w-30 on my motor with 182K on it. I think if youre motor doesnt show any signs of trouble, switching to Mobil 1 wont be an issue, especially if you go to a thicker weight.

 

only thing i would recommend is redline mt-90 in the transmission. shifting can be notchy otherwise.

syn

$30 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 will be fine for diffs/xfer case.

 

X2

 

The only thing I would add to this discussion is that be sure not to use a GL-5 lubricant in the transmission. The Redline MT-90 is a good choice because it meets the GL-4 specification requirements.

GL-5s have additives that are corrosive to soft metals, like the syncros, found in the Toyota manual transmission.

 

How much of this is hearsay, or do you have first hand experience of failed synchros in 1st gens? I'm asking because the owner's manuals says to use GL5.

 

I know for a fact toyota recommends gl4 fluid in the transmission due to the presence of brass syncros...not sure where you read it recommends gl5.

Even if there is no first hand experience, the toyota engineers recommended not using gl5....so why not listen to the people who designed the truck?

 

Owner's manual doesn't indicate a preference:
Oil type:
Gear Oil API GL-4 or GL-5
Recommended oil viscosity:
SAE 75W- 90

http://www.toyota.com/t3Portal/document/om/OM35729U/xhtml/OM35729U_OM0017.html?locale=en (page 230)

 

I suppose there could be some urban legend stuff in this. It is something that does get repeated without hard evidence either way. I certainly have no experience with failed syncros when using GL-5 gear oils. On the other hand, I do have experience with Redline MT-90 working very well in the the tranny.

Have you yourself actually used GL-5 fluids in your trans?

 

I have an automatic. I use GL-5 in the diffs and T-case. I'm just curious because GL-4 oil is not carried in any of the auto parts stores in my area.