Fixed my gear grinding problem with MT90 + MTL

[xcye]

Redline MTL + MT90 is the way to try first if you have gear grind problem.
The following are the facts that lead to this conclusion.

1. Right after I bought the car (a R32 GTR), I did tranny fluid change with 4L of MT90. But the down shifting from 5 to 4 ground.

2. Then, I flushed the tranny with LightWeight Shockproof. The 5 to 4 grinding went away completely. However, 1 to 2 ground during warm up, and 2 to 3 did not shift as smooth as with MT90 in it. Besides, the shockproof contains sulfur which slowly eats away brass syncho.

3. I drained all LW Shockproof and filled the tranny with 3L of MTL + 1L of MT90. There was no grinding in any gear change after that. But, 1 to 2 and 2 to 3 still did not shift as good as with just MT90.:|

4. I drained out a little more than 1L of the mixing out and put in the same amount of MT90. The tranny felt like new after that. Shifts were smooth like butter. :drive:

So, I'd say MTL + MT90 cocktail is worthwhile to try first if your gear grinds. You can start with MTL only first, then add in MT90 like I did. Or you can go with MT90 first then add in MTL (I'd prefer second way, since MT90 is the right weight oil to use in R32 gearbox, while MTL is a little too thin for the bearings).

Anyway, I hope my experiment can help some of people to avoid or delay costly and time consuming gearbox changes.

[mcfly]

why did you opt for light shock proof over heavy shock proof.

[xcye]

why did you opt for light shock proof over heavy shock proof.

I figured heavy shockproof would be too thick for our cold climate.
This car is may daily car. So, warm up time actually counts.

[Zulu]

Heavy Shockproof is a very nice tranny oil once it is warmed up. Makes the tranny feel very smooth !

Looks like pepto bismol when coming out of the bottle except you need to heat the oil in order to people able to use a hand vaccum/pump tool to fill your tranny.

[xcye]

Heavy Shockproof is a very nice tranny oil once it is warmed up. Makes the tranny feel very smooth !

Looks like pepto bismol when coming out of the bottle except you need to heat the oil in order to people able to use a hand vaccum/pump tool to fill your tranny.

However, all shockproof oil contains sulfur which does eat soft metal slowly. So, I would say stay away from shockproof if there is any other alternative.

[mcfly]

However, all shockproof oil contains sulfur which does eat soft metal slowly. So, I would say stay away from shockproof if there is any other alternative.

I agree,
The MSDS for super light, light and heavy shock proof contain sulfur.

'Oxides of carbon, phosphorous, calcium, molybdenum, and sulfur'

Sucks but for the dieing boxes it is a good choice.

[Terrh]

ATF works wonders on bad syncros as well. 0.5L into the trans with whatever other oil you are using.The heavy shockproof doesn't seem to mix with anything but I assume it works just as well as ATF to fix work syncros anyways.

[xcye]

ATF works wonders on bad syncros as well. 0.5L into the trans with whatever other oil you are using.The heavy shockproof doesn't seem to mix with anything but I assume it works just as well as ATF to fix work syncros anyways.

Adding ATF is equivalent to adding friction modifier as the engagement of auto trany clutch packs is in some sense similar to syncro engagement. MTL and MT-90 have these kind of modifier already in them.

[BlackAura]

Interesting....I've noticed a bit of 5th -> 4th crunch, so I may have to try this when I change my fluids in a month or two. I think GTR-Guy had Redline in the tranny already....but I'm not sure which type off hand.

[maximus140]

Just curious..where did you get the Redline MTL?

[xcye]

Just curious..where did you get the Redline MTL?

I got it from Mopac in Calgary.

Here is the URL link for them:http://www.mopacautosupply.com/

[Dragon Humper]

I've always wondered what the hell the shockproof is ment for if it eats brass. Is it only ment for crashboxes that have no syncro's (Jerico, Dogbox's, etc..)? Seams kinda stupid to put sulfer in there if the brass can't take it.

My box's syncro's are a little sluggish too, 1st is always a bugger to get into from a standstill and 4th is crunching a bit on the up/down shift. Must give the Dextron splash a try this week.

Jon.

[Dragon Humper]

UPDATE


Found out my level was lower than I thought and needed almost a full litre to top it up. I checked it when I first got the car and it was crystal clear but I guess i was in a hurry and didn't take note on how far I had to stick my finger in to get a sample.

Put in aprox. 500ml of synthetic Dextron mixed with 200ml of Lucas Auto Trans supplement. Shifts are much more smooth with no grinding in 4th any more. Even poking it into 1st at a stoplight is much easier to do now.

I don't think that the level being a little low was much of a factor as there was virtually no change in performance in the tranny from cold to oper. temp. At oper. temp there would have been oil all over everything in there and should have functioned identically to the level being full.

So far me likey....


Jon.

[xcye]

That's good to know.

UPDATE


Found out my level was lower than I thought and needed almost a full litre to top it up. I checked it when I first got the car and it was crystal clear but I guess i was in a hurry and didn't take note on how far I had to stick my finger in to get a sample.

Put in aprox. 500ml of synthetic Dextron mixed with 200ml of Lucas Auto Trans supplement. Shifts are much more smooth with no grinding in 4th any more. Even poking it into 1st at a stoplight is much easier to do now.

I don't think that the level being a little low was much of a factor as there was virtually no change in performance in the tranny from cold to oper. temp. At oper. temp there would have been oil all over everything in there and should have functioned identically to the level being full.

So far me likey....


Jon.

[cobrAA]

is there a DIY on how to change your tranny oil ??

I have grinding only on my 2nd.