New transmission: "Break in" period?

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Without going in to too much detail, I'm installing a remanufactured (by Honda) auto transmission in my '02 4cyl Honda accord next week.

My current plan is to run the new transmission with non-synthetic Honda ATF-Z1 for the first 3k miles, then make the switch to SF Autoglide (Z1) and run it until the new transmission hits the 10k mark, when I'll drain+refill again to increase the amount of SF Autoglide in there. From then on, I intend on doing one drain+refill of SF Autoglide every 10k miles.

How many thousand miles would you give a new transmission to "break-in," and would it be preferable to run the manufacturer's non-synthetic ATF during this period? Should I perhaps avoid running a synthetic ATF until much later than 10k miles?

FYI, for those not following my previous "Racing" thread, this car will continue to be autocrossed occasionally, as it only consists of one launch and one shift (not hard on autos; something else caused my current trans failure).

Once the new transmission is fully broken in, and depending on what temps I see while daily driving with the factory cooling/warming setup, I will reinstall my auxiliary cooler, possibly with a 180*F fluid thermostat and/or inline filter and resume autocross with SF Autoglide in there...
 
Personally, I would just use your fluid of choice in there from the get go. I would imagine the friction plates and steels will be engineered to work from day one, so why try to "break them in". I am rebuilding an older dodge tranny from my daytona and when its done I am simply filling it with the normal ATF+4 and driving it like I normally would.

Most of the tranmissions shop I have known don't insist on any breakin period. My fav local shop just tells people honestly whats wrong with the tranny, rebuilds it, and they go on their merry way with it. And this guy has VERY few return customers due to repeat failures(except a few guys who race).
 
Hmm, sounds logical. What about the differential (open) in there?
 
Its a reman, most parts are already broken in.
Feel free to change the ATF to remove any initial break-in wear or assembly dirt.

What are you going to do to prevent the reman from suffering the same faith as the previous transmission?
 
What is the break-in proceedure for a new set of gears?

All new gear sets require a break-in period to prevent damage from overheating. After driving the first 15 or 20 miles it is best to let the differential cool before proceeding. I recommend at least 500 miles before towing. I also recommend towing for very short distances (less than 15 miles) and letting the differential cool before continuing during the first 45 towing miles. This may seem unnecessary but I have seen many differentials damaged from being loaded before the gear set was broken in.
I also recommend changing the gear oil after the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new gear set.



http://www.ringpinion.com/FAQ.aspx#37
 
Well to sum it up (in increasing importance):

-SF Autoglide with 10k drain+refill intervals (this could be a bit excessive)
-Relocated the aux cooler for a lot more airflow (70% blocked by the bumper for 3yrs)
-(most likely) Install a 180*F thermostat when I reinstall the aux cooler, depending on what my new trans temp gauge tells me about the factory setup/routing (it never felt right during the coldest parts of the winter, with the aux cooler installed inline after the factory radiator cooler/warmer)
-(possibly) Install an inline remote filter with 10k change intervals
-Not drive like a #@$%! on remote country backroads
-Not take it to open track events (too much heat and shifting for it to handle)

Basically, if I can keep the ATF temps stable and clean year round (especially during the winter), I should be good, but the most important factor is the significantly lower amount of abuse it'll see, along with the realization that it isn't bullet-proof
wink.gif


Autocross really isn't hard on the transmission at all; It's one launch, a shift into 2nd, where it remains locked for the rest of the run. The only issue here is the temperature of the AT during the hottest summer events, where I suspect the engine coolant is dumping heat into the ATF once I stop moving (I can tell by the hesitation getting in/out of D4). A thermostat-activated fan for the aux cooler could help, if I find that my changes/improvements aren't sufficient.

Once I finally obtain/build a more competitive, alternative car (late 80s early 90s NA 4 banger), I'll most likely continue to use my Accord as a daily driver. It's just too nice of a car to trade/sell before 200-250k miles
wink.gif
 
Quote:


What is the break-in proceedure for a new set of gears?

All new gear sets require a break-in period to prevent damage from overheating. After driving the first 15 or 20 miles it is best to let the differential cool before proceeding. I recommend at least 500 miles before towing. I also recommend towing for very short distances (less than 15 miles) and letting the differential cool before continuing during the first 45 towing miles. This may seem unnecessary but I have seen many differentials damaged from being loaded before the gear set was broken in.
I also recommend changing the gear oil after the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new gear set.




Sorry, in case you didn't catch it, it's a FWD Transaxle. The diff and transmission share the same case and lube.
 
Forgot to mention, from what I've been told, the Honda remans only retain the orginal case. Everything else inside the case is brand new (I guess they've depleted their supply of new factory replacements). I could be wrong, either way you guys have all given my the advice I needed
smile.gif
 
Quote:


Forgot to mention, from what I've been told, the Honda remans only retain the orginal case. Everything else inside the case is brand new (I guess they've depleted their supply of new factory replacements). I could be wrong, either way you guys have all given my the advice I needed
smile.gif





They didn't deplete their supply of new ones they just saw the extra profit margin in re-using the old cases that are still within spec. Much to do with the cost increases in the metals markets I am certain.
 
Cool, just curious do you know of any more detailed info in regards to the Honda remans and their longevity?
 
I've never seen any manual recomending any speacial break in for a tranny. Shops that rebuild may have recomendations and they will vary greatly, but I've never seen anything from manufactures.
 
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