All Things Chev

[the evil twin]

snip...
I do like the sound of the manual TCC switch as an addition, plus a temp gauge.
snip...
I reckon being able to hold gears going downhill with an Auto would be how I'd want to drive it.

A manual lockup is the absolute ducks guts.
I put one on my TB42 Auto and it essentially turns the box into a manual as far as engine braking is concerned and drops the gearbox temp by heaps when towing or down the beach.
There are some circuits around with speed sensing etc etc but I kept it simple.
An "arming" toggle switch on the centre console, an old school foot dip switch on the floor by the left foot rest to engage/disengage and an LED reminder on the dash to show when it was engaged.
All up cost was less than $30

I pulled the trigger on Ebay for an Engine Guardian style dual input temp indication, warning and fan controller... $169 delivered
http://www.ebay.com.au/itm/181187370...84.m1439.l2649

There are several programs on the net showing TCC lock-up in 2nd and 3rd for the guys doing a lot of towing.
They are using 60 to 70% PWM at 0 TPS ramping down to 0 PWM at 10% TPS.
IE the TCC is almost but not fully locked at 0 throttle but releases by 10%.
They are doing that not so much for engine braking but to keep the revs up for the climb up the other side of the Hill.

The main problem I have with info from America is that most Forums are orientated to using their trucks as haulers not 4WD's in our sense of the activity or fully the other way where they are using them as extreme 4WD

My only concern with the 4L8x series boxes is the Yanks and their discussions with the overrun clutch's burning out if you get too aggressive with Engine Braking IE fully locked TCC with 0% throttle...
BUT...
we aren't using anything like the GVM that they are, indeed, I reckon we may be only 50% or less so the loads on teh clutch packs must be heaps less.

[FNQGU]

LOL - too much info ET. You are confusing the shit out of me, which isn't hard when it comes to technical stuff... Are you saying that some programs can give 60-70% engine braking when you take your foot off the accelerator, and as you start to accelerate it drops off at the 10% mark?

Manual lockup switch sounds like the plan.

Engine Guardian looks interesting...I'll watch with interest to see what you think.

[the evil twin]

ROFL... bad habit of mine.

You can program the Lock Up and where it occurs between 0 to 100% of TPS at whatever speed.
The tranny "programs" are presented as tables so you can set (for example) in 2nd gear the Torque Converter Clutch (TCC) locks at 0% throttle above 20 KPH
This means that if you are coasting down hill with foot off throttle faster than 20KPH in 2nd the TCC will lock and give you engine braking.

Your next step in the tables might be (still for 2nd gear) 10% throttle above 40 KPH, 20% 40 KPH, 30% 45 KPH, 40% 50 KPH etc
This means that when you open the throttle at the bottom of the hill the TCC now unlocks allowing the Torque Converter to do it's thing.
Now assuming you stay in second and accelerate to, say, 45 KPH and the TPS is 30% or less (IE you aren't flogging up the next hill) then the TCC will lock again.
Push the throttle past 30% or drop below 45 KPH and the TCC will unlock because you obviously want more power.

Unrelated to Chevy's but us patrollers are used to the magic 80 KPH figure.
That is where most of the Patrol Auto's are proggy'd to lock up the TCC in OD if the TPS is telling you it is "cruising"

[FNQGU]

Just had a yarn with Wholesale Automatics, who actually recommend a rebuilt Nissan RE4 transmission with upgraded Torque Converter and Valve Body as opposed to the Chev unit. They say that the Nissan Auto once upgraded, trounces the 4L80 series gearing for 4wdriving, and also for reliability issues. Will keep researching and am waiting for a bit more info from them.

[Gecko17]

Just had a yarn with Wholesale Automatics, who actually recommend a rebuilt Nissan RE4 transmission with upgraded Torque Converter and Valve Body as opposed to the Chev unit. They say that the Nissan Auto once upgraded, trounces the 4L80 series gearing for 4wdriving, and also for reliability issues. Will keep researching and am waiting for a bit more info from them.

I was told the same thing. The reason I went with the chev was that it was way cheaper, new and I didn't have to fly,twice, to Melbourne.

@ BenK, have only played around with the CompuShift II a little bit as have no idea really what I'm doing... was hoping to catch up with ET to see what he'd done/recommended.

[FNQGU]

I'm actually thinking about giving this install a crack myself with a bit of assistance over beers from a mechanic mate. Might force myself to learn about automatics...

Quote today was as follows:
Cost for a Heavy Duty Extreme Fully Reconditioned Nissan 4 Speed RE4R03A Overdrive Automatic Transmission with Heavy Duty Extreme Valve Body & Double Kiln Bronzed Torque Convertor all Pre-dyno Tested is $5100 inc gst.

Comes with: Bell Housing and Filler Tube/Dip Stick

Required Options:
2 X Extra Large Oil Cooler $195 inc gst (each)
5 Meters Of Heavy Duty 10mm ID Cooler Hose $88
4 X Stainless Steel Hose Clamps $12 “set”
6.5L Complete Drive Plate Assembly $195
Factory T.Bar Assembly with Centre Console Assembly (second hand) $540
Automatic Pedal Pad and Plate Box $85
Stand Alone Transmission ECU $1995

The ECU is the Compushift II which is an expensive bit, but adds a lot of options for setting it up right and monitoring everything. Comes with:
*Wiring Harness
*Dash Display/Programmer
*Choose Between Full Manual Or Full Automatic At The Touch Of A Button
*Lock-Up Manual Control for 100% Engine Braking At The Touch Of A Button
*New Inhibitor Switch
*New Revolution Sensor
*Built In Temp Gauge
*Australian Back Up & Technical Support

Not sure where to mount the twin oil coolers though. The area in front of my radiator looks pretty bloody cluttered as it is. Where have you guys got your coolers mounted? I have heard of coolers being mounted beneath vehicles but I'd be wary of airflow and damage issues.

[FNQGU]

Again looking at the space in front of my radiator. On the Drivers side I have the aircon condenser and in front of it is the engine oil cooler. On the passengers side is a thermo fan for the radiator.

I just went for a spin in a 2004 GU with a Chev and Auto conversion, and in his setup there is no Thermo fan, just his Transmission Fluid cooler, oil cooler and aircon condenser. He has the stock 4L85E and has had it in for about 12 months. He doesn't have a Transmission Oil temp gauge, but claims it has never had an overheating problem. I don't think I like the idea of having no Thermo fan though, and instead I am thinking I'll mock up a dummy tranny cooler for size, and will work on making some brackets to try and fit the cooler between the radiator and the thermo fan before I pull the trigger on doing the auto. Might have to change the Thermo fan out for a slimmer model too, but will look at that as I go.

And while I am at it, I might as well fit that reduction gear in the transfer case too... Hopefully Love Key70 has some more of those 63% gears ready soon.

[the evil twin]

I have the Engine watch dog on mine as of yesterday...
My coolers are up under the tray with minimal air flow so have a fan fitted.

In the small amount of K's so far with the Fans turned off so I can set the warning temps...

The engine warms up and then doesn;t move more than a few degrees.

The 4L85 with the TCC locked and cruising at 110 KPH sits on 55 degrees (tranny temp not fluid)
Working in traffic and urban stop/go it gets to 65 degrees pretty quick then stabilises at that.
Turning the Fans on doesn't do a thing... this could be because of how the tranny ports the fluid IE I need to find out if there is a thermo arrangement in the tranny controlling fluid paths or if it sends 100% of the fluid thru the cooler no matter what.

I haven't had a big load in the back and I haven't done any loooooong hillclimbs yet

At those temps the Tranny is only just warming up and thats with bugger all airflow thru the cooler

[FNQGU]

Cheers mate, good info.

With your Auto install, how close does the crossover exhaust (my term) get past the auto pan?

eg. on my manual box it sits like this. I imagine the auto pan gets very bloody close to it or the exhaust has been modified somewhat.


I have had a good look at the space in front of my radiator, and am more inclined to fit the twin oil coolers for the tranny fluid just in behind the bull bar on each side in this space, if I can knock up a couple of brackets. Routing of hoses should be pretty simple I think and I can put a guard below each cooler with a few holes in it, and then add a 6" thermo fan above it to blow back through the cooler....I think....

Front of the vehicle to the left of photo.

[the evil twin]

I haven't got my Ute at the moment... it is in getting bar work, steps, scrub bars, panniers etc etc but from memory when I was under there the cross over pipe goes just under the very back of the Torque Converter and the pan for the box is behind the pipe and is also bloody enormous.

The chevy box is quite large and sits back further than the manual box so the cross member has to modified and the tailshaft shortened