I recently purchased a 97' Montero Sport from a freind with 120K miles, and learned he nevered changed the trans fluid. A mechanic told me with that many miles, changing it will do more harm than good. Does anyone have an opinion on this?
Thanks, Dan

 

I've heard contradicting opinions on this for pretty much any transmission. IIRC, you can sum it up this way...

If your tranny is screwed, you're already screwed anyways. May as well know the reality of it and get it fixed instead of having it fail at a truly inopportune moment.

On the upside, the Mitsu Automatic tranny in my Gen I is truly a marvel in reliability so I wouldn't be surprised if your 97's tranny still works after the fluid change.

Also, once you know it works fine, I recommend a flush (not a simple drain and refill) every 1-2 years. FWIW, a flush is where they start your engine, let it warm up, set the parking brake & put it in drive (maybe), and while the tranny's engaged and operating disconnect your tranny cooler in lines and allow the fluid to drain while they refill it from the fluid level check spout. Once clear fluid comes out the turn off the engine, reconnect the hose and your done.

Cost for this service in the San Francisco Bay Area is ~$75 and since I take mine off road (1990 v6 Automatic) on hard core trails like the Rubicon, etc. I do this service annually instead of the normal recommended service interval.

 

Yup.. like he said! The 97-98 Montero Sport was equipt with a practically bullet proof Asian Warner transmission. I've never seen one of these go out EVER in any of the Mitsubishi SUV models that were equipt with it (Gen I and II Montero's and the Montero Sport models listed above. I'd go ahead and do it with a full flush being sure to BACKFLUSH the trans cooler as well. Note that your Asian Warner transmission requires Dextron II so you don't really have to use the more expensive Mitsu Diamond SPIII if you chose not to. The above mention method of flushing the transmission by disconnecting the cooler lines works great but will NOT back flush the cooler.

Joel, CA

 

While we are on the topic of fluids..

What can you guys tell me about synthetics? I just traded in my '98 MS for an '02 and was considering chaging all the fluids with synthetics. It almost to the 60k mark which is the first recomnended change for many of them. It also means the end of the waranty so wether i use what they recomend does not matter for waranty reasons.

Are synthetics as good as the recomended fluids? What are the advantages to sythetics?

Can you also give me a list of what you recomemnd I run in the difs, trany, tcase, and engine oil?

 

Highly recommended for the engine, xfer case, and diffs- but i'd stick with Mitsu Diamond SPIII for your 02 auto trans.

Joel, CA

 

I definitely echo what Joel's saying regaring using Mitsu fluid over synthetics in the tranny. I'm even willing to make a wager that you'll be rebuilding your tranny if you use synthetics (regardless of what they say they're compatible with).

 

I think Redline makes the best gear oils. Also, you should use a GL-4 fluid for the transfer case. Mobil does not make one. Redline does.

 

Real 100% Synthetic fluids, meaning PAO's and esters, are superior in every way to regular non-synthetic fluids. That includes the Mitsu Diamond SPIII tranny fluid. Running them will give you the maximum protection you can get from friction, shear, and oxidation, and have the added benifit of lasting much longer than a regular mineral oil making extended drain intervals possible if you so choose.

I just read 2 old wives tales in this thread. Changing your old worn out, burnt transmission fluid is always a good thing, and if your tranny goes after you do this, it would have blown with the old worn out fluid quicker. Synthetic fluids, including transmission fluid, exceed the specifications from the manufacturer. That means they are better fluids. They are resistant to higher heat, run cleaner longer, slicker which reduces friction, and have lower flow point temps. Why wouldn't you put a better fluid in your transmission if you could?

The syn specific companies all make good fluids with varing price ranges, and products. Some, like Mobil 1, don't offer fluids for every need. I have been using Amsoil in everything I own for about ten years now and believe it has helped many of my vehicles hit over 100,000 miles and a few of them have ran over 200,000 miles with no major problems, and sold in good running order. Here is the synthetic transmission fluid I run in my 2000 montero sport 3.0 with over 70K:
http://www.amsoil.com/storefront/atf.aspx

You will find links on that page to the various other fluids and info you can obtain from Amsoil. Redline and royal purple also make good synthetic fluids, but cost a little more.
Before anyone says somthing about it, Im not a dealer. I've noticed the difference synthetic fluids have made in my various engines and transmissions and like to share the info with others who may not know of the many advantages synthetic fluids have over mineral based.

Daniel

 

I second that on Amsoil. I've used their synthetic trans fluid in the 3 Mitsubishis I've had with no problem.

I even used ATF+3 where Diamond SPIII (ATF+4) was specified. Many other Mitsu owners have as well, as until recently, you couldn't get ATF+4 at the local Auto store.

I'm also skeptical about GL-5 gear oil harming your transfer case, as opposed to using GL-4.

Sure, if it calls for GL-4, I'd try and get it, but a lot of stores don't have it, or if they do, it says "GL-4/GL-5".

 

that is an ages old tale that may have been true on a crappy 71 pontiac, but is NOT true on anything modern.
change your fluid.