Transmission Light/P0740 Code/Judgement is 7

[grunze]

'96 Q45 140k

Had some transmission slippage and did a BG flush a few months ago. All OK until this light came on. Both my Actron and internal diags give the code for Torque Converter Clutch Solenoid Valve problems. Reset. Light came back on in a week.

Manual:EC-80 A/T control unit detects the improper voltage drop when it tries to operate the solenoid valve.AT-59 Possible causes: 1)Harness or connectors(The solenoid circuit is open or short). 2)T/C Clutch Solenoid Valve.

Suggestions on next step?Will we hurt anything by driving it?If it is the solenoid valve, how difficult to replace?

Thanks.

[Q45tech]

After measuring solenoid resistance to make sure it is not open, I would reflush transmission [BG Quick Clean] and replace all ATF just in case some dirt is clogging solenoid action.

Solenoids don't usually fail [open] but they do get clogged up and wiring/connectors can become open so one checks continuity.

I could think the valve body removal and new solenoids would be ~~ $1,000.

BUT at 140k and FOURTEEN 14 YEARS is beyond normal functioning life of transmission so the lock up clutch driven by solenoid may be worn or worn out.

The point is be prepared for a new Nissan remanned transmission if you plan on keeping Q much longer.

The longests I've seen these 94-96 units last is 15 years or 200k.Everyone of our 94-96 customers has had a new transmission. But Atlanta cars are driven more in annual mileage.

Be very very careful of National Chain Transission shops as they can charge too much for too little and 12 months later [after warranty] you are stuck needing the new transmission anyway.

All about whether you want to spend $1,000 or $3500.

You might find a decent 94-96 transmission at a junkyard but age is against you now unless you can document less than 80k before pulled!

[maxnix]

All about whether you want to spend $1,000 or $3500.

You might find a decent 94-96 transmission at a junkyard but age is against you now unless you can document less than 80k before pulled!

From what we have seen here over the last seven years, more like $1k/per annum for rebuilt, or $3.5K for another 10 years of not worrying about AT.

[lino]

.....You might find a decent 94-96 transmission at a junkyard but age is against you now unless you can document less than 80k before pulled!

What about a JDM transmission?

[Q45tech]

Since Japan is traffic nightmare I would expect each Japanese MILE to have more shifts than a Atlanta MILE or especially a Georgia MILE.

All depends on which city in Japan the Q/President lived in before it donated its transmission for export.

[maxnix]

'96 Q45 140k

Had some transmission slippage and did a BG flush a few months ago.

It's be nice to know the appearance and condition of the old ATF, and if a pan drop, inspection of it and the replaced filter screen revealed anything.

Also what the prevous maintenance was as far as you know.

Often when the mechanical ATF exchanges are not a regular maintenance item from new, a late life exchange without a pan drop will load the interior filter screen with gunk and detritus starving the planetary gears until they fail. Jerry Tucker and a board member learned this the hard way and now that shop always performs the pan drop and fliter exchange with any ATF mechanical exchange.
Modified by maxnix at 8:18 PM 6/16/2009

[grunze]

[QUOTE=Q45tech]After measuring solenoid resistance to make sure it is not open

Thanks Tech.........Looks like I can check resistance at the A/T Control Unit under the driver side dash. It should be 10 to 20 ohms between 5 and grnd. Does that sound right?

[grunze]

Got a quote for a reman from Joe for a net cost of just under $2,100 after $400 core rebate and shipping both ways. How's the experience here with a reman from Infiniti. Where do you get to spend the $3,500 for new??

[grunze]

Bought this one at 56k. Drained irregularly but not BG flushed until a few months ago. I think they dropped the pan but couldn't swear to it. Thanks for the suggestion. Will definitely follow up.

[maxnix]

Dropping the pan requires gasket, one time use bolts, O ring and interior filter. If you didn't supply the parts and require that particular service, I can assure you they didn't do it.

[maxnix]

Got a quote for a reman from Joe for a net cost of just under $2,100 after $400 core rebate and shipping both ways. How's the experience here with a reman from Infiniti. Where do you get to spend the $3,500 for new??

Nissan rebuilds these on a production line in Tennessee, with everything replaced with rebuilt or new. As close to the no longer available new that you can get. Much better than all but a custom rebuild in a precision shop with a technician experienced with the RE4 (of which there are almost none outside of Nissan).

Change exterior filter, rear main seal and third motor (transmission) mount and associated exhaust hangers. I think the new transmission comes with a new turbine speed sensor.

Add the auxiliary ATF cooler when installed.

[lino]

The Subaru SVX 4EAT transmission has problems and appartently the transmission in the SVX is also used in the Nissan Pathfinder.

This website gives a description of the issues:

http://www.subarusvx.com/faq/transmission.html

This place specializes in rebuilding them with upgrades. I wonder if they would a good place for Q45 transmission rebuilding:

http://www.drwtransmission.com/subaru_svx.htm