All Things Chev

[Gecko17]

Bit of feedback on how the 4L85E gearbox after doing the Meetup trip.

Around town - 10/10 - awesome mod. Sure beats the pedal work involved with the manual box.
Uses more fuel but thats 'cause you can't keep your foot off the loud pedal or the smile off your face

Cruising - 9/10 - just lopes along with the TC engaged and the 4th ratio locked up is taller again than manual 5th.
This means 1800 RPM is just over 100 KPH with 35's (that will vary with tyre manuf as all manuf are different dias and none are true 35)
Deducted a point because it usually drops straight to 3rd when the TC unlocks which is a slight annoyance.

Towing - 9/10 - same comments as cruising really. 35's are too big for "ideal" towing with the 3.9 diffs but that is tyre selection not the tranny.
Next trip I will throw my 33's back on to see how they go and I reckon they will be heaps better.

4x4 - 7/10 - Off road is a two step process. Point it, plant it. I need to get a manual TC lock up switch sorted and then it will be 9/10.

Fuel consumption - Not quite as good as I hoped. I averaged 20 LPH for the trip towing my van (2 tonnes) for over 1/2 of it but in fairness a few more tweaks of the programming and 33's would def improve that figure. By how much I don't know

I found it relatively easy to program the Tranny Computer (well at least the one that was supplied as apparently there are a few oprtions) but as I still haven't got my head quite around how the tranny works I took baby steps and still don't have it quite how I want it.

Will have to catch up with you at some stage ET... I'm still not sure my Compushift II is working properly or, more to the point, programmed properly.

I notice you said that you still had the 3.9:1 diff ratios? Is that correct? Mine were changed back to 4.11:1... I'm ment to be running 33in tyres but have 35's on at the moment.

[brooks]

Nice job, looks very neat.

[FNQGU]

Gecko / ET - Help! What sort of TPS does this setup need for the CompuShift II and how is it mounted?

BenK

[the evil twin]

Gecko / ET - Help! What sort of TPS does this setup need for the CompuShift II and how is it mounted?

BenK

Dunno, sorry.

1800 brunswick might help or try a wander around the Yank Chevy websites

[FNQGU]

Ok, thanks. Will go and see Gryphon Engineering here in Cairns. Was hoping I could work this out myself, but I am hitting a brick wall and need some guidance for this bit.

Also, have you got the Transmission Fluid temp sender installed? I don't have one yet, but am considering it.

The coolers are huge! 300mm x 300mm and there are two of them. Took a whole lot of mucking around to fit up.

[FNQGU]

Well, I have got to say this - Wholesale Automatics will not get return business from me. Great product, very poor service. Once they had my money they took weeks before bothering to freight the transmission despite numerous promises. Then, when the expected delivery date came around and I rang to confirm the delivery details, I found out again that it hadn't even been put together, followed by another broken promise that the lot would leave in the morning. 3 more days later it was dispatched, just in time for me to have to go back to work for another month. Also despite all my questions, and their assurances this was a once stop shop and everything was included in the kit, they failed to include the gear selector linkage or advise me that the Throttle Position Sensor isn't included in the kit and needs brackets made up for mounting with this engine. Very disappointed Rodney, time you had a bit of a look at your customer service.

[FNQGU]

Just a bit of an update - I've slowly been going through the process of changing my manual over to Automatic and now have it on the road for the first time. The setup I went with was the Re-built Nissan Auto with the whole hog of Wholesale Automatic's upgrades as opposed to a brand new Chev 4L80E or 85E. There wasn't much in it really, but I suppose what swayed me was Rodney's insistence that it would be a much better setup and easily able to handle the HP. The Compushift II was also added. There isn't much point in showing photos of an manual-auto change as it is covered elsewhere, but these are some of the issues I faced that are Chev specific.

a) The crossover exhaust from RHS back to the turbo needed modifying a bit. It was just a cut and re-weld job but it was touching the pan and the sway bar and I couldn't get it bolted up correctly so there was also an air-leak. A simple job for any exhaust mob.
Before...


After:


The kit from Wholesale Automatics also did not come with a Throttle Position Sensor, which it should have done. I won't whinge here, but my dealings with them were less than satisfactory. Gryphon Engineering who are a Brunswick Diesel authorised installer, came to the rescue and had a TPS for me. They fitted it up while I was at work so I didn't get the chance to get into the how's and why's, but it fits up to the fuel pump here:



I'm now in the testing phase but so far am very impressed with the swift changes of the Nomad valve body and the extra drive-ability of the auto around town. So, so, much better around town. The thing that I suppose I need to work out most is the running temps, and the gear change points. The head unit for the Computshift II is telling me that the box is running at around 85 degrees C, which seems a bit high to my uneducated self. I've only done about 30klms on it so far but haven't mucked with any of the calibrations yet either.

The head unit itself is mounted here on a home-made bracket at the moment. It is nice and clear and provides easy accessibility if I want to switch to manual operation of the transmission or anything else that I haven't yet worked out properly.


The actual Compushift II computer is mounted up under the dash, behind the glovebox. It is just that bit higher up there, than behind the kick-panel where most TCU's live. If anyone wants a pic of it, sing out and I'll add one.

The manual TCC lockup switch is currently mounted here, although I am still undecided if this is where it will live:

Apologies for the poor quality phone photo...

I didn't bother including any pics of the transmission itself as they are all on the Wholesale auto website, but one issue I did have (albeit minor) was that the reconditioned box has some horrible grind marks on the face that mates to the Transfer Case that needed sealing. Not very professional in my opinion.

Oh, lastly, the RPM sensor apparently causes some 'issues' with the Compushift II, and Wholesale Auto's recommended that it not be connected. Not a big deal as I wouldn't look at it anyway and it doesn't affect programming (apparently).

Next up is to sort out the programming and test it all out some more.

Edit: 85 degrees C seems to be about right for town driving. If anyone has some data on temps for various uses, I'd very much appreciate an idea of what i should be looking at. I'm guessing min temps of 80 degrees, through to max temps of about 110 degrees when labouring?

[FNQGU]

Well, I took the truck for a good run over the weekend. From Cairns out through Herberton to Stanary Hills and then to Chillagoe for the night before a relaxing run back to Cairns this morning. Did a bit of 4wd work in both Low and High range at Stanary Hills and I'm happy with the 43% reduction gears with the auto. I think it is just right in Low Range now and my car was a lot better to drive than the other standard 3ltr Patrol Auto that was with me, so that part has been a success. and I'd highly recommend it for anyone else opting for an Auto conversion.

I got a bit of a fright at one point when the throttle jammed on at full revs when I was overtaking. It seemed to get stuck when I floored it and I had to tap the accelerator pedal several times before it eventually released. I'm still not sure what caused this to happen so if anyone has any suggestions, I'm keen to hear them.

The temps are also a bit of a concern and I might need to make some changes to the setup. Going up the Kuranda Range it got to 101 C then dropped back to 93*C during the run to Mareeba. The run up to Atherton didn't see much temp changes really. It hovered between 93 - 97 Celsius, then up to 101 Celsius on the range up to Herberton.

The dirt road work also saw the transmission working fairly hard at speeds between 50kph - 70kph and temps around that same 101 celsius mark. Bush 4wdriving hovered between 101 celsius up to 103 celsius, with no real opportunity to cool down due to minimal airflow through the coolers.

The nice flat easy run back from Chillagoe to Cairns this morning was much easier and only saw temps in the vicinity of 82-83C.

I'm now keen to re-locate one of the ATF coolers and am thinking of adding a thermo-fan to help with temps in the slow bush driving.

I need to sort the TCU programming at Highway speeds too. The TCC doesn't really want to lock up much at the moment, and also tends to jump out of locked at the least amount of throttle. I used the manual switch quite a lot to overcome that tendency but might re-calibrate the TPS as well.

I am noticing that the turbo seems to be working harder at Highway speeds, and the boost figures seem a bit different now too with boost figures of between 5.5 - 6.6Psi when sitting on 100kph. Several times the alarm went off on the boost gauge as the turbo went over 10 or 12psi. The truck isn't quite as willing to overtake as it was when it still had the manual box either, and the turbo quickly reaches high Psi figures without really much gain in pace. Revs however are nicely lower when cruising and sit just above 1700rpm with the TCC locked. At idle, the boost now seems to sit at 1.1psi for some reason too, whereas before it was zero.

EGT's are also a bit higher and approach 400 celsius if going up the slightest hill. With the manual box they were generally always under 300 unless I was giving it some or it was under load in a high gear. At highway speeds it was generally sitting around the mid-300 mark or would drop to around 300 C if cruising with no load or power on.

So I have a couple of things to fix/adjust or work on, and I still need to get more familiar with driving an Auto 4wd but so far I am really enjoying the improved drive-ability of the 6.5TD engine.

[FNQGU]

Re-calibrated the TPS this morning. Found that it was out. The below photo shows the problem. The middle number should never be lower than the left number or higher than the right number.


I also adjusted the TCC Maximum Throttle disengage setting up from 35% to 40%, allowing a bit more use of the engine's torque when cruising at highway speed before it kicks down to 4th.

I also adjusted the TCC Enable Speed to 80kph, although I might raise it back up if I find that this is too low, which I suspect it might be.

I then adjusted the TCC Disable percentage to 90% (from 5%) which is when the TCC will come off as your speed drops below your set 80kph enable setting.

I also lowered the Downshift Offset to 85% (from 95%), which means I need to give it a bit more throttle before it will kick down in a situation where I want to pass a vehicle etc. etc. Might even need to come down a bit further yet, but I'll see how it goes.

If anyone else is using the Compushift II with this engine, I'd be interested in your general system settings.

[nissannewby]

The boost increase is expected due to the load the auto puts on the motor.