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Discussion Starter #1
someone told me that once a vehicle hits a certain mileage, it's not advisable to change the transmission and differential fluids b/c it effectively "shocks" the system and can make mechanical slippage more likely. the speaker of this nugget of wisdom is someone with mucho land rover experience; but there is an equally strong chance he's just wrong and responding to someone's vignette. :dance:

is he simply alluding to the ak-47 concept where tolerances between moving parts tighten with build-up of accumulated crud? or is it best to just hold what you've got if things are going well at 150k+?
 

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:? :roll: :lol:

Depends on who you ask. It the same as the debate on dino oil or synthetic, you will get different answers. So let me give you my answer via a question.

When you ENGINE reaches 100K miles, do you just stop changing the oil because it might "shock" the system? Trannies and diffs are wear items just as the engine is. Think about it.

Search will give you several threads on this topic and the right vs wrong banter.
 

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2002-2005 Range Rover MkIII / L322
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I'd have to say a big fat hell no to the diff fluid...but tranny fluid a solid maybe.
 

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2006-2009 Range Rover Sport
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I think the only reason that I would not change the type of transmission fluid is that it is almost impossible to fully drain out the old stuff.
Consequently you may end up with a mix that is not fully compatible.

Cheers,
Keijo
 

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2002-2005 Range Rover MkIII / L322
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I always thought the problem with the trans oil was if it's not changed regularly you get a buid up of sludge which was not the cause of probs, but when you change the oil with fresh detergents in it, it can dislodge gunk and then cause problems.

So the problem only arises if you buy a 15 y/o car thats never had a trans fluid change - but then I would think that the fact it has 15 y/o fluid is possibly worse than the remote chance of floating gunk bits?

The trans cooler blew on my P38, so over the next 200 miles probably had 20L of fresh tranny fluid! Then I had a full change one with the new cooler so thats as good a flush as you're ever going to get!

Just my 2p
 

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I think Dan's right on the money. maybe change a little at a time to avoid that? slow drain/fill over a couple weeks? or change frequently for the first couple months of new ownership.
 

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Keijo said:
I think the only reason that I would not change the type of transmission fluid is that it is almost impossible to fully drain out the old stuff.
Consequently you may end up with a mix that is not fully compatible.

Cheers,
Keijo
THat's why you flush before changing the fluid and filter.
 

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true enough rrtoadhall,

I was answering from the DIY perspective as a transmission flush is not something you can do yourself unless you have access to a high pressure flush machine.
Irrespective of a change in fluid type the flush will replace the fluid in the torque converter as well.

The thing is that some manufacturers don't recommend a flush and you might actually cause some problems with internal seals for example because of the pressure introduced.
If you are paying for a shop to carry out your service, I would think about getting some sort of guarantee for the flush for your specific transmission.

Regarding the gunk and floaties, that's exactly what the flush will remove.

Cheers
 

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Keijo said:
true enough rrtoadhall,

I was answering from the DIY perspective as a transmission flush is not something you can do yourself unless you have access to a high pressure flush machine.
Irrespective of a change in fluid type the flush will replace the fluid in the torque converter as well.

Who said anything about high pressure or a flush not being DIY? Search my posts for tranny flush. I;ve written it up a couple times. :thumb:
 

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rrtoadhall said:
Keijo said:
true enough rrtoadhall,

I was answering from the DIY perspective as a transmission flush is not something you can do yourself unless you have access to a high pressure flush machine.
Irrespective of a change in fluid type the flush will replace the fluid in the torque converter as well.

Who said anything about high pressure or a flush not being DIY? Search my posts for tranny flush. I;ve written it up a couple times. :thumb:
About 5 years ago when I first got my 99 Bosch I went to a good shop that services transmissions as one of there specialties and first thing the mechanic did when I ask about a full transmission flush is head for the computer and brought up my 99 and he turned around and said that it was NOT recommended on the rovers. So what I do now is just drop the oil, measure it and put back the exact about of new oil.
 

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Skip R said:
About 5 years ago when I first got my 99 Bosch I went to a good shop that services transmissions as one of there specialties and first thing the mechanic did when I ask about a full transmission flush is head for the computer and brought up my 99 and he turned around and said that it was NOT recommended on the rovers. So what I do now is just drop the oil, measure it and put back the exact about of new oil.
Good info. What about replacing the filter screen?
Or do you just change the oil out?
 

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My friend, please let me clear this bulls;;t rumour up for you. Being a petroleum engineer I hope gives you some confidence in my experience and specialized knowledge on the subject of lubrication and wear of mechanical parts and movers. YOU MAY CONTINUE TO CHANGE YOUR FLUIDS AS OFTEN AS YOU LIKE!!!As a matter of FACT I would suggest swtching over to synthetics asap as the molacules are smaller and absorb into the metal with up to 40% more penetration. Most fleet operation's have done so and that's how they get a half million miles out of a highway truck before selling them to someone who then gets another half million miles out of them. The older they get the more you should change the oil to keep the parts clean and well lubed. PERIOD. 8-|= Cheers Big-T
 

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Who said anything about high pressure or a flush not being DIY? Search my posts for tranny flush. I;ve written it up a couple times.
been lookin for those posts but no luck, can you give me a link??

120k very dirty trans oil, gearbox working fine, no service history..... almost convinced myself to drain/flush/filter change etc, as crudy oil just cant be good? right?

Gordon
 

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Discussion Starter #15
try searching tranny fluid or diff fluid is what i did after toad admonished me earlier. if i search any more than i already do, my marriage will end.
found some conversation on the topic with those search terms that was spirited and enlightening.
 

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I'm pushing 135k+ and my tranny shifts like buttduh... :thumb: ...At least once a day, I'm using sport mode and the gears are shifting tight, even at high Rs...Mind you, I don't thrash on the ol' girl, but lets just say, there will be no carbon dating done to her motor...I'm sure the fluid could use abit of refreshing, but as for me, until I start to feel the shifts slip, that's when I'll service the Borg-warner... `)
 

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LR spec on diffs, transfer box and autobox (Inc filter) every 30 000km's

75W90 in diffs

ATF Dexron III (not Dexron II) in auto box and transferbox

Engine every 10 000ks or sooner if lots of town use, I prefer a 15W40 in these engines (Ideal for our climate)
 
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