# 2015 2.0 diesel Performance transmission rebuild



## NelsonR (May 25, 2020)

I just got done Race tuning my Cruze diesel and realize my Asian trans won’t last long with max power. Does anyone have rebuild kits available for these?


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## Ma v e n (Oct 8, 2018)

Raybestos makes clutches for them, I would contact them and see what friction compounds they offer.


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## 15CruzeTD (Oct 23, 2019)

If you find anything post it here, because I would be maybe be interested


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## pandrad61 (Jul 8, 2015)

From my searching our trans isn’t a popular one for performance rebuilding. Basically add a massive oil to air cooler to keep temps down. I think stock it stays at 200 which is high in my book. Run amsoil SS since it’s basically the only performance fluid option.


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## MP81 (Jul 20, 2015)

The next time the trans cooler lines fail (because I'm sure they will), I'll likely do exactly that. Won't have to worry about failing lines again.

Do we know if the air shutters are linked to trans temp at all? @Snipesy


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## Snipesy (Dec 7, 2015)

I


MP81 said:


> The next time the trans cooler lines fail (because I'm sure they will), I'll likely do exactly that. Won't have to worry about failing lines again.
> 
> Do we know if the air shutters are linked to trans temp at all? @Snipesy


No clue. The TCM does broadcast the oil temp over CAN... So the CCM which controls the shutters can see it. As for if it does anything with that information no idea.


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## pandrad61 (Jul 8, 2015)

MP81 said:


> The next time the trans cooler lines fail (because I'm sure they will), I'll likely do exactly that. Won't have to worry about failing lines again.
> 
> Do we know if the air shutters are linked to trans temp at all? @Snipesy


I think it would but have no proof. Trans temp is a temp changed by airflow same as radiator. I wouldn’t see why computer wouldn’t also do it for trans.


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## Snipesy (Dec 7, 2015)

At the very least it should monitor overtemp protection which the TCM can trigger on its own.


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## MP81 (Jul 20, 2015)

Anyway to trick the sensor and see what the shutters do?

All of this is moreso just to determine where the best place for the trans cooler would be. Given the trans likes to run hot anyway, having it behind the shutters might not get a ton of airflow. The best spot for it might be directly behind the upper grill opening.


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## pandrad61 (Jul 8, 2015)

MP81 said:


> Anyway to trick the sensor and see what the shutters do?
> 
> All of this is moreso just to determine where the best place for the trans cooler would be. Given the trans likes to run hot anyway, having it behind the shutters might not get a ton of airflow. The best spot for it might be directly behind the upper grill opening.


My plan was to remove the front grill block off plates, that should improve cooling all around. From radiator to condenser to inter cooler and oil cooler, a 100% increase in intake size should move a lot of volume. That being the case is think the aero shutters would stay closed.


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## MP81 (Jul 20, 2015)

For ours, I'd like to leave them in for the aero purposes that led to them being installed in the first place. But having the trans cooler behind the opening should give it plenty of flow. I'm not concerned about it being in front of the radiator since the engine runs so cool anyway. If it does, somehow, get warm, the shutters can open up.


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## pandrad61 (Jul 8, 2015)

MP81 said:


> For ours, I'd like to leave them in for the aero purposes that led to them being installed in the first place. But having the trans cooler behind the opening should give it plenty of flow. I'm not concerned about it being in front of the radiator since the engine runs so cool anyway. If it does, somehow, get warm, the shutters can open up.


I’m in Florida so any advantage the condenser can get I’ll give it. With performance sticky rubber I’ve already accepted the MPG loss what’s a bit more. Still gets better then most mpg anyway.


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## NelsonR (May 25, 2020)

pandrad61 said:


> From my searching our trans isn’t a popular one for performance rebuilding. Basically add a massive oil to air cooler to keep temps down. I think stock it stays at 200 which is high in my book. Run amsoil SS since it’s basically the only performance fluid option.


Trans temp is not what I’m worried about, I want it to hold, if your trans is working properly you won’t have heat issues, By properly I mean not slipping or blowing thru lock up that’s the only way your gonna make to much heat.


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## pandrad61 (Jul 8, 2015)

NelsonR said:


> Trans temp is not what I’m worried about, I want it to hold, if your trans is working properly you won’t have heat issues, By properly I mean not slipping or blowing thru lock up that’s the only way your gonna make to much heat.


Stock trans holds at about 200, if you really push it I can see it climbing. These trans aren’t meant for heavy abuse.


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## MP81 (Jul 20, 2015)

Trans temp _is_ an issue with these things. The fluid always seems to run hot, so it's something that needs to be addressed if you want to upgrade the **** inside.


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## Ma v e n (Oct 8, 2018)

Just like engine coolant and engine oil, trans fluid needs to reach a certain temperature, and maintain it. It needs to be hot enough to evaporate any moisture that collects, it need to be hot enough to get to the desired viscocity. If it can't do these things trans life will suffer. Overcooling is something that can happen.


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## pandrad61 (Jul 8, 2015)

Ma v e n said:


> Just like engine coolant and engine oil, trans fluid needs to reach a certain temperature, and maintain it. It needs to be hot enough to evaporate any moisture that collects, it need to be hot enough to get to the desired viscocity. If it can't do these things trans life will suffer. Overcooling is something that can happen.


Sure but it’s well documented standard that 180 is about the optimal temp for trans fluid. Where the trans will live longest at. 200 is high but not out of realm when it comes to super tight FWD packaged engine trans combo vs say a truck that has the trans out of the engine bay.


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## MP81 (Jul 20, 2015)

Personally, I think the transmission having an "internal" filter probably doesn't help. At least on a transaxle with a regular filter, it gets the fluid _somewhat_ out of the hottest parts of the transmission.


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## pandrad61 (Jul 8, 2015)

MP81 said:


> Personally, I think the transmission having an "internal" filter probably doesn't help. At least on a transaxle with a regular filter, it gets the fluid _somewhat_ out of the hottest parts of the transmission.


Yah no replacement filter is dumb, add that to no dip sticks you just check in N with a hot engine and I hate modern companies for it.


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## Ma v e n (Oct 8, 2018)

pandrad61 said:


> Sure but it’s well documented standard that 180 is about the optimal temp for trans fluid. Where the trans will live longest at. 200 is high but not out of realm when it comes to super tight FWD packaged engine trans combo vs say a truck that has the trans out of the engine bay.


Optimal for what trans fluid? What does 200F do that 180F doesn't? The fluid itself being too hot is only an issue if starts to breakdown at that temp, or if it's viscocity goes out of range(full temp viscocity is rated at 212)
The fluid in the gen2 gets checked at 194F +/-. Notably lower than that and the trans isn't even filled to proper level. Running it at 180 wouldnt even allow you to check fluid level properly.

The Gen1 sets a trans temp too high dtc at 302F, and it clears at 284F. 

If notable durability improvements were available inexpensively that still allowed for proper bearing and gear protection and fuel economy goals by lowering trans temp well below 200F that GM would do so. 

Fluid and oil technology has come a long way since everything used conventional fluids, and we ran things cold. Old school well documented standards, and rules of thumb don't directly apply to the vehicle we drive today. The 6.2L V8 Detroit diesel GM came out with in the early 80s for trucks and SUVs had 130hp/240lbft. Compare that to the 2.0 and the 1.6. l

If the thing heat soaked and couldn't maintain fluid temps....sure, put an auxiliary cooler on it. I don't see a benefit to it on a healthy vehicle.


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## pandrad61 (Jul 8, 2015)

Ma v e n said:


> Optimal for what trans fluid? What does 200F do that 180F doesn't? The fluid itself being too hot is only an issue if starts to breakdown at that temp, or if it's viscocity goes out of range(full temp viscocity is rated at 212)
> The fluid in the gen2 gets checked at 194F +/-. Notably lower than that and the trans isn't even filled to proper level. Running it at 180 wouldnt even allow you to check fluid level properly.
> 
> The Gen1 sets a trans temp too high dtc at 302F, and it clears at 284F.
> ...


Optimal for all automatic trans fluids. GM didn’t use high quality synthetic in the gen 1 trans, I assumed you have a gen 1 since you posted in gen 1 diesels. High quality synthetic can do fine in 200 but components start to break down quicker as does the fluid. 

Gm won’t care about trans temps and components life since their goal is to clear warranty miles and done. Otherwise why would they recommend BS lifetime transmission fluid. 

Gm putting cheap fluid that have problems from the begging is a norm. I run amsoil SS since it’s a better synthetic made to handle the abuse. If it took dextron 4 I’d run other brands but for what the trans takes doesn’t have huge options

we assume it’s a healthy trans, however GM as with all manufacturers are profit driven And only allow enough cooling to Meet the minimum standards where MOST trans will run past warranty, anything more and be happy. If you’re planning on tuning and pushing the performance up then you’ll need to address added cooling AND a trans that can handle the TQ. unfortunately performance rebuild parts aren’t made for our trans.Heat is a huge trans killer especially in light duty components, so added cooling will only improve odds at longer life.


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## MP81 (Jul 20, 2015)

And the issue with heat in this trans (the AF40-6, specifically) is it seems to run pretty hot in a few of our vehicles.

Ours doesn't seem to have the same issues in the winter that is does in summer - so, to me, that definitely says it's a cooling issue (the stock cooler seems to have less trouble maintaining the correct temp with colder ambient temps, rather than when ambient temps are hotter). 

The other perk of going to an aftermarket cooler? You no longer have to deal with the stock lines that are notorious for leaking, and are an absolute bitch to replace.


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## Ma v e n (Oct 8, 2018)

Optimal for all transmissions is just a silly concept. There are multiple different fluids across all the different brands, hell GM alone specifies no less than 4 different fluids currently across their range. There's no one optimal fluid, no one optimal engine oil, no singular best engine operating temp, how do you defend there could possibly be one best trans temp? 

Your statement about GM not caring about component life due to their desire to clear warranty mileage is contradictory. And recommending lifetime fill is because they believe it can last the warranty period.

It's been my understanding that AW-1 is Aisin ATF6, a synthetic fluid. If you say that current AW-1 is non-Synthetic I'd love to see any kind of current reference. 

Of course we are making assumptions about a trans being healthty. I even specified that a healthy trans that maintains it's temps doesn't need cooling. One that sees heat soak and climbing temps does.... 

Just throwing additional cooling at the trans without determining if it's needed is wasteful of budget, and overcooling can have deleterious affects. System pressure can be off of optimal when temp is out of spec, fluid film thickness and strength, and viscocity changes can cause shifting aberrations. Just like overcooling the engine can cause sludge buildup, corrosion, and PCV/intake system fouling.


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## Ma v e n (Oct 8, 2018)

MP81 said:


> And the issue with heat in this trans (the AF40-6, specifically) is it *seems* to run *pretty* hot in a few of our


Like I mentioned, one doesn't know what temp this trans wants to be at. Or at what temp accelerated wear occurs at. I find it hard to believe that 200F is too hot.


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## MP81 (Jul 20, 2015)

I've not had Torque running when we have issues, but I'd not be surprised if its a good bit above 200 on ours.

Then again, we hardly drive it anymore, so...


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## Snipesy (Dec 7, 2015)

MP81 said:


> I've not had Torque running when we have issues, but I'd not be surprised if its a good bit above 200 on ours.
> 
> Then again, we hardly drive it anymore, so...


Think I've put on maybe 1,000 miles the past 6 months . Used market gonna be full of low mileage cars if this keeps up.


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## MP81 (Jul 20, 2015)

Yeah, we haven't put much on - but we did take it to Charlotte, NC and back just recently, so that was about ~1300 miles. Otherwise, it goes a month or two between fillups now.

My Volt runs EMM every few drives now.


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