[gordon]

I have a GC 2003, 4.7 V8 Limited.

Recently I have been getting the P0740 code. Having done exahstive research on this, it could be a number of issues - right up to folks getting a new/reman transmission.

So, I have decided to replace the solenoid pack and transmission oil pump, along with new fluid and filter.

There are a number of folks selling these items out there. I am looking for reccomendations, I want to make sure the solenoid pack and oil pump have all the latest upgrades ect.

Thanks in advance.

[CoolGuyDave]

do a search for transgo shift kit

[gordon]

So here is what I intend to do;

Solenoid Pack
New Pressure regulator
New filters
Shift kit
Add an external tranny cooler
New fluid.

This is about all I can do without taking the tranny off the car, which I would need to do to change the pump. My betting is that lower fluid pressure is causing it not to lock up at HWY speeds. Changing all the above should address any pressure issues. I also got trans overtemp twice whilst towing during this fault condition, I am assuming this fault condition may have caused the tranny to warm up a bit. I figures adding an external tranny cooler will help in the future.

If all this does not cure the problem, I will look for a rebuilt transmisssion.

Chance you take I guess.

[sandfreestyle]

you should already have an external tranny cooler.

[narnwv]

Originally Posted by sandfreestyle

you should already have an external tranny cooler.

only those with the factory tow package or "tow prep" package have the external cooler. The rest of 'em only have the one built into the radiator.

[Searcher1]

Originally Posted by narnwv

only those with the factory tow package or "tow prep" package have the external cooler. The rest of 'em only have the one built into the radiator.

I believe he meant adding one if it doesn't have one already

[Planetcat]

I thought none of the WJ's came with external trans coolers. I have the factory tow package and my owner's manual and FSM specifically say something to the effect of "because of the large internal trans cooler in the radiator, no external cooler is supplied". Adding an external one would not hurt.

[gordon]

I checked last night - I do not have an external tranny cooler. The only tranny cooler I have is the one in the radiator.

I went to Summit last night and picked up a universal external tranny cooler.

It was interesting to read that lowering yout tranny temp from 200 to 180 can double the life of your tranny.

[sherker55]

which one did you pick up, and where are you going to mount it?

[gordon]

The transmission cooler I am fitting is a universal one by Summit racing;

http://www.summitracing.com/parts/SUM-G4966/

There is "Just" enough room to fit it in the front grille. It is an easy fit, uses special plastic threaded rods to mount through exisiting radiator coolers. The transmission cooler line return coming out of the radiator will feed into the top of this extra cooler, the output of which will feed back to the tranny cooler return line.

I am just finishing this job up as I have been off ill. This weekend I will be tackling the Transgo shift kit. This will be in 2 parts, upgrade of the Valve body parts, this should be fairly straight forward. The second part of the upgrade kit includes 2 upgrades to the pump - this is the tricky bit as the tranny will have to come out to get at the pump.

I have all the gear to do this, but this is the first time I have ever done this, so I am a bit nervous about doing it. I will report back on my progress.

The pump upgrades fix the TC lockup issue which I am 90% certain why I was recieving the P740 TCC lockup failure code in the first place.

Also, when I dropped the pan and got rid of the old tranny fluid I removed the magnet from the bottom of the pan. This had a film of "Dust" on in which I removed with a rag. Apart from that there were no other flakes, chunks, shaving wahtsoever. So, even with 110k miles i am fairly confident that the rest of the tranny (steels, clutches) is ok and this is normal wear and tear.

I will report back in a week or 2.

Cheers Gordon

[JeepinWJ86]

How come both of my Jeeps have tow package, but the trans cooler is built in the radiatior!!! only external one is 03 p/s cooler the 04 is built into the ac condesor?????????????

[gordon]

Every Jeep will have a Transcooler built into the radiator. Some of them also had the external (additional cooler added) mine did not. The smaller element in front of the main radiator is the AC condenser. I have mounted my cooler in front of this, but more to the center so the airflow is not too obscured from the condenser.

[mrtosh]

I recently did the solenoid pack and Transgo HD shift kit along with filters. Love the way it shifts now. Just be prepared for erratic shift firmness for the first couple weeks as the TCM learns and adjusts for added line pressure.

[gordon]

So, here's an update;

I removed the valve body from the trans which is still in the car. On a table, I done all the VB work with the transgo shoft kit. All fairly straight forward, just took my time. I have also installed a new solenoid pack with all the latest upgrades. Also put in new pressure regulator switch, and over/under run speed sensors. Put the VB back in the tranny, installed new filters and gasket. Replaced tranny sump pan, the rest of the upgrade will be done with the tranny removed.

I now still need to solder the resitor accros pins 1 and 3 of the pressure transducer and do the pump upgrades.

Whilst I am down there I have decided to put a new rear main seal on the engine behind the flywheel and put a new oil pan gasket for the sump.

I am stuck right now getting the oil pan off, I have removed everything and it just won't budge, stuck fast. I have been gently levering all round the pan with a crow bar and tapping it with a rubber mallet with no success. Does any one know how to get the sump off?

[gordon]

Originally Posted by mrtosh

I recently did the solenoid pack and Transgo HD shift kit along with filters. Love the way it shifts now. Just be prepared for erratic shift firmness for the first couple weeks as the TCM learns and adjusts for added line pressure.

I am not changing the tranny but with the shift kit and soenoid change - should I be loooking to getting the tranny reset so it will do the quick learn proceedure? Or will it be ok as is?