[klutched]

Anyone put a lockup on their auto gv? Going down steep decents is shit not having any engine braking...

Would an auto trans shop be able to make me up one? And what sort of price would i be looking at?

Cheers

[Gwagensteve]

A manual lock isn't a solution to inadequate gear reduction. Stock crawl ratio on an auto GV is pretty average. Add tall tyres and it's going to run away, locked or not.

My sierra at 99:1 numerical engine brakes like crazy in 1st low without a lock.

Sorry this isn't answering your question, I'm just suggesting that you might be disappointed even if you get it done.

[klutched]

How much would it help?

5.8s are on the cards so that would help a lot. Crawler gears are an unknown atm.

How have you achieved 99:1 ratio in your sierra?

[Zook_Fan]

With 5.12's and 6.5's I'd imagine which obviously you can't get in your GV.

If you run with 5.12's to keep a common gear size and then go to a 4.24 transfer you can get down to 53.2:1 which should be okay for an auto depending on how much you actually crawl. You'll go up to 60.6:1 with the lower diff gears.

[fordem]

klutched wrote:

Anyone put a lockup on their auto gv?

As far as I know the SQ series GV should have an 03-72LE transmission, which is an Aisin Warner AW4 derivative and should have a lockable torque converter - shouldn't require more than modified electronics to lock it at will.

I have the AW4 in a Mitsubishi, and locking the TCC can be done by switching a single wire to ground, however, I would not recommend that approach, if you forget it locked, you'll cause problems - you want some sort of "push to lock" with an auto release, if you shift gear, switch the engine off etc.

Drive the vehicle on a level road and allow it to shift up through the gears, when it gets to third keep a close eye on the tach, directly after it shifts to fourth, watch for the tach to drop a few hundred rpms - that'll be the TCC engaging - now, without removing your right foot from the gas, gently depress the brake with your left foot, you should be able to get the TCC to disengage (the tach will jump a few hundred rpm), and re-engage when you release the brake.

You should be able to see the same thing in third if you have OD disabled.

As long as you have the electronically controlled TCC (even the three speed autos had them), you can lock it by manually switching the solenoid.

[got_bar_work]

Is your gv auto or manual. Auto should fit gears but manual will not as they have different output shaft

[Gwagensteve]

There's some other issues to consider with a manual lockup. The lockup solenoid isn't designed to engine brake a car at full load. If the solenoid fails because you're overloading it in 1st gear, you'll have crappy fuel economy on the highway.

A manual lock is one more thing to think about when off road in a scary situation. If it works effectively it will be very difficult to stop the car in gear with the brakes, because to do it you'll need to stall the engine. Once the engine has stalled, there's no pump pressure to hold the gear, so you are in neutral, regardless of whether the engine is running or the converter is locked. That's scary, and you'll have to remember to unlock the converter to start the engine and regain the ability to hold a gear.

Obviously, leaving the converter locked and putting the lever in park is going to cause issues, especially if the engine is running.

I know patrol owners have run manual locks for years (for similar reasons you are thinking about one) but I'll stand by my original comments - if your AW-4 has inadequate engine braking, it's because your car has inadequate gearing, not because of converter slip.

Steve.

[christover1]

My auto LWB Vit on 30's has good engine braking with 4:24 tranny gears.
I have to accelerate down steep slippy hills to prevent it from locking all 4 wheels.
I agree with Steve, gearing is the answer