Apologies if this or something similar is posted elsewhere. I tried searching for a poll, but I did read through some of the extensive threads and captured usernames, years, mileage and outcome. If you are finding this from other sites, this is an issue that, in addition to Xterras, affects Pathfinders and Frontiers. Where the radiator fails and coolant mixes with automatic transmission fluid. THIS DOES NOT AFFECT MANUAL TRANSMISSION MODELS
What is SMOD?
eath (basically what your transmission fluid looks like after mixing with coolant.) The coolant and transmission fluid mix due to an internal failure in older model Nissan radiators.
Here's a Good Description on SMOD Causes, by Forum Member Robert Bills:
How can I tell if I have SMOD?
If you take the time to read the thousands of posts theorizing about the cause of SMOD you will probably be more confused than ever, particularly so when you realize that many if not most of the opinions are based upon pure conjecture and repetition of what others have posited without any supporting scientific or forensic evidence to back up those opinions.
The most reliable evidence suggests that SMOD is caused by a manufacturing or design defect in the Calsonic radiators supplied between 2005 and 2009 which results in the failure of a joint in the ATF cooling tube allowing coolant and ATF to mix with disastrous results for the automatic transmission. (Calsonic is a wholly owned subsidiary of Nissan.) This conclusion is supported by these facts: (1) defective Xterra radiators have been dissected to observe the faulty joint; (2) a Nissan/Calsonic radiator with a different part number was introduced for the 2010 model year superseding the 2005-2009 radiators; and (3) incidents of SMOD are negligible for the 2010+ model years.
Many people believe that the use of any ATF other than "genuine Nissan Matic S" can cause SMOD, a belief which appears to be based entirely upon the fact that in 2009 Nissan announced that Nissan Matic S would supersede Nissan Matic J and recommended that only Matic S be used in Xterra automatic transmissions. However, it should be noted that Nissan made this recommendation for all
Nissan automatic transmissions using Dexron III/Mercon type ATF, not just those vehicles with a history of SMOD. This, when coupled with the fact that multiple refiners market "Matic S equivalent" ATF, suggests that there is no provable connection between the type of ATF used and the incidence of SMOD and that the timing of the change in recommended ATF was coincidental.
If you buy a 2010 or later Xterra, and confirm that your truck has the radiator with the new part number, then SMOD should not be a concern for you.
If you buy a 2005-2009 Xterra, then you should confirm that there are no traces of coolant in the ATF that indicate current or past SMOD (by visual inspection of the coolant, looking for deposits under the radiator cap and in the coolant overflow tank, and/or a chemical test of the ATF by Blackstone Labs), then immediately do the "radiator ATF coolant tube bypass" discussed in multiple threads on this website or replace the radiator with a quality aftermarket unit. Just factor the expense into the price you are willing to offer for the truck.
As for ATF, any quality ATF that is labeled as the equivalent of Nissan Matic S will be fine. Some people like Amsoil. I like Valvoline Maxlife Dex/Merc ATF http://www.valvoline.com/pdf/maxlife_atf.pdf.
Symptoms include: Strawberry Milkshake like sludge on underside of radiator cap. (Check when engine is cool.)
- Rumbling / shaking around 50+ from the transmission (feels like you are driving over rumble strips)
- General transmission issues (slipping, poor shifting, hard shifting, etc)
What can I do to prevent SMOD? / What is ByPassing?
You could upgrade to the new Nissan radiator (part # needed) or put in an aftermarket radiator.
Alternatively, you could potentially 'ByPass'. ByPass = Re-routing cooling lines so the transmission does not utilize the radiator for additional cooling. Members have mixed views on this. Some say its fine, others feel that it reduces cooling capacity, especially in Xterras that are off-roaded or tow. "ByPassing" is a preventative measure. Once damage has been done its either new parts or possibly a flush.
Nissan also has an extended warranty in place (see below).
Additional information on by-passing:
- Observed transmission temps: https://www.thenewx.org/forum/11-powertrain-driveline/65980-thoughts-observations-engine-auto-trans-cooling.html
- How to bypass: https://www.thenewx.org/forum/15-how-tos/25955-how-bypass-radiator-transmission-cooler-pbr.html
What can I do if I have SMOD?
First, if you do or suspect you have SMOD - stop driving the Xterra as soon as possible to limit further transmission damage.
Next, most people end up with a New / rebuild of Transmission and new radiator system + updated fluid and removal of all contaminated fluid. Typically Nissan does cover this.
Alternatively you could try flushing the system and just changing the radiator. Some members have reported they have "saved" the transmission that way. Depends on how long you have been driving with this issue and the level of damage done to the transmission.
Other general information:
- Nissan has issued an extended Warranty that covers transmission failures related to the flawed radiator design. Covers 2005-2010, 100% till 80,000 - over 80k deductibles are required.
- Link to extended warranty: http://www.nissanassist.com/web/Radi...qs.php?menu=22
- So far there have been no failures from 2009 on wards (and the 1 2008 listed is likely a false positive).
Disclaimer, (in other words, before you freak out): The data reflected in this post, and on this board is of a small subset of total Xterras on the road and sold. Overall, the Xterra is a reliable truck. Most users who find this post are here because they have SMOD, few people sign on to say "everything has been great". You'll also note that the data so far reflects early year Xterra's (2005, 06 & 07). These are also the years with the most Xterra's sold and those that have the most miles on them. However, these are also the years with the old coolant type and radiator design.
Saved = Typically new radiator, hoses, and multiple flushes with Matic-S
New Transmission: Exactly that. Some covered, some weren't.
I plan to make this list eventually more sort-able and capture counts. But for now here it is.
Additionally I'd love to get data points for those that have by-passed how long they have been running it, whether or not they have an aux cooler, and if they have had any issues (overheats or still SMOD).
Lastly, I'm trying to find out what year the switch from Matic-J to S occurred (updated: 2009 = fluid switch) and when (if at all) a new radiator part was issued. <-- General concensus is that a new radiator has been implemented. Exact date unclear (either in MY 2009, 2010, or 2011).
PLEASE ADD YOUR NAME IF I DON'T HAVE YOU ALREADY.
SMOD List (updated 10/30/2015)
• 56,000 – mac_man2507 (new transmission)
• 120,000 – 6pack (saved)
• Texterra (saved)
• 65,000 – synjohn
• 115,000 – GhostX (saved )
• 103,000 – TRON (saved)
• 79,000 Riehle (unknown)
• Draines (unknown – frontier)
• 100,500 – tsiturbomightym (new transmission)
• 92,000 – zambonikane (new transmission)
• 56,000 – alexterra (new transmission)
• 80,000 – rockdog (new transmission)
• 84,000 – micheljm (new transmission)
• 90,000 – Hinsx (new transmission)
• 103,000 – guedesigns (unknown)
• 82,000 – jaysonics (upgraded to 2011 Xterra)
• 72,000 – KpnObvious (new transmission)
• 110,000 – Blucas (new transmission)
• Machine>Matter (new transmission)
• 39,000 nporecords (new transmission)
• First class X (new transmission)
• 40,000km vandman
• 130,000k - mango (saved)
• 78,000 - pkiddddd (new transmission)
• 77,000 - Dirtbag (new transmission)
• 137,000 - Salsa E *2005 Pathfinder* (saved)
• 80,000 - Texterra (saved - 2 flushes and new radiator) - Now at over 316,000+ miles w/out issues!
• 105,000 - skipper172
• 175,000 - gorillamel (Saved: by-passed, but had overheat issues and by-pass removed. Got SMOD sometime after.)
• 115,000 - mtbx (new transmission)
• 117,000 - EsotericSYN (saved)
• 114,000 - chicago111 (saved)
• 120,000 - mmkco (saved?)
• 123,391 - Strat1tude (saved)
• 59,778 - jeffnjm3 (new transmission)
• 127,000 - drink
• 330(km) - Scoop
• 120,000 - nixorz
• 69,000 - alex_godmar (saved)
• 93,000 - DucXterra (new rad and trans)
• 69,000 - Shagaroo (new rad and trans)
• 168,000 - raleighx (new rad and trans)
• My3rdx (saved)
• 98,000 p.staff
• 160,000 – paffcon (saved)
• 85,000 – klrkknt81 (new transmission)
• 06_xterra_s (saved)
• 50,000 - Xterra3100 (new transmission)
• 63,000 - az_jerry (new transmission)
• 69,000 - dutch169 (new transmission)
• 86,000 - Mnemonic (new transmission)
• 80,000 - Metal-X-Militia (new transmission)
• 105,000 - oskon187
• 207,000 - Notread - (possibly saved?)
• 176,000 - DriverX
• 74,500 - dignow (new transmission)
• 81,000 - G&L (new transmission & new radiator)
• neflihim (saved)
• nolesfan (saved, then bought a 2013)
• 117,000 - socaloverlander (flushed / saved)
• 111,000 – White07x (new transmission)
• 63,000 xguy4life (saved)
• 84,000 camaro194 (new transmission)
• 65,000 miketerra07 (new transmission)
• Frasersxterra (saved)
• 75,500 - Chug
• 106,000 - Weber58 (new transmission)
• 79,300 - Evan77 (new transmission)
• 105,000 - JohnCB (new radiator + flush)
• 124,000 - Un4Seen (new radiator + flush)
• 137,000 - ThorX (New rad + flush, lasted for 1 year, needs rebuild or new trans)
• 158,000 - sullivan (new radiator, flushes, saved)
• 61,000 - Ramsker (new transmission & radiator - dealer covered)
• 100,013 - jimmpotter
• 75,000 - painroller (new radiator + trans)
- List members and mileage / time they have been bypassed
- 2007 X - KillSwitch, bypassed for 30k miles, no SMOD or issues
- 2005 X - Surf and Snow - bypassed for 3 years, no issues
- 2007 X - rthinchey - Bypassed at 78k. now at 94k and no problems
- 2005 X - Tib - Bypassed for over 3 years, over 40K miles since bypass, no aux cooler, no smod, no issues.
- 2008 X - El'Zilcho - Bypassed for 5,000 miles, no issues
- 2005 X - shralp313 - Bypassed @ 110k
- 2010 X - g6620 - Bypassed @ 36k, plus external cooler
- 2006 X - unamused - Bypassed @ 35k, now at 100k, no issues