Manual shifting your auto for engine braking

[Pinger]

The newer computer controlled transmissions cannot be hurt by downshifting. Move the shifter into first at 100 mph, it will not be downshifting the vehicle slows enough to make the downshift safely. I still downshift on a regular basis when I want to supplement the brakes or hold the vehicle back downhill without using the brakes.

But will allow reverse to be selected. What was GM thinking?

 

[Rock Hard Concrete]

I utilize manual shifting often when towing. It really helps going down a grade pulling over 15k. I try not to force the transmission to take the hit, I usually floor it momentarily to get the gear I want then move the shifter to that position, or Rev match a down shift. Yes, you can Rev match an automatic if you know what you're doing.

 

[Scooterwrench]

I like the old column shifters. I'm still on the fence about putting a 5spd in Smoky and if I do I want to try to design a column shifter for it. I cut my teeth on 3 on the tree. 5 on the tree would be badass!

 

[boy&hisdogs]

I manual shift mine only when towing heavy or driving on steep mountain roads.

As many others said, brakes are cheaper to replace than transmissions.

 

[Supercharged111]

I don't know how true this is, but I have seen it mentioned that the overrun clutches aren't all that strong on a 4L80. I know I've smoked them on a 700R4 and they left the building on my dually as well. Not sure what to chalk it up to though.

 

[Scooterwrench]

The problem with downshifting the 4L60/700R4 is your foot is off the throttle,TV cable not pulled,line pressure down,clutches applying slowly and lightly. All bad! I guess if you shift before you lift you can reduce the slippage by keeping the line pressure up during the downshift.

 

[1998_K1500_Sub]

The problem with downshifting the 4L60/700R4 is your foot is off the throttle,TV cable not pulled,line pressure down,clutches applying slowly and lightly. All bad! I guess if you shift before you lift you can reduce the slippage by keeping the line pressure up during the downshift.

At least on the 4L60/700R4 the the pump pressure gets increased when the manual valve is in "2" or "1".

On the "E" versions, I'm not sure what the ECU does with the pump pressure at 0% TPS, and/or if the pump pressure depends on the manual valve position like it does on the non-E 4L60/700R4. I should go look...

 

[Scooterwrench]

The E trannys have all kinds of parameters that can be tuned into the PCM and I think there is a device that can be installed in the tranny to increase line pressure regardless of PCM input. Bet MaxEx can explain better.

 

[NickTransmissions]

The E trannys have all kinds of parameters that can be tuned into the PCM and I think there is a device that can be installed in the tranny to increase line pressure regardless of PCM input. Bet MaxEx can explain better.

Larger boost/rev boost in the 700R4/200-4Rs and larger dia boost valves for the 4L60E/4L80E. Pair all that with higher pressure pump pressure regulator springs and you have a higher linear line pressure margin (spring) and higher ceiling and more rapid line rise (larger boost valve and rev boost valve where applicable).

You can also manually adjust the electronic pressure control solenoid in the 60/80 as well as stick interior springs in the AFL valve train (4L60E).

All those mods (either by themselves or paired with good ecm-tcm tuning) will increase and improve line pressure characteristics in the 4L60E and 4L80E.

 

[L31MaxExpress]

Larger boost/rev boost in the 700R4/200-4Rs and larger dia boost valves for the 4L60E/4L80E. Pair all that with higher pressure pump pressure regulator springs and you have a higher linear line pressure margin (spring) and higher ceiling and more rapid line rise (larger boost valve and rev boost valve where applicable).

You can also manually adjust the electronic pressure control solenoid in the 60/80 as well as stick interior springs in the AFL valve train (4L60E).

All those mods (either by themselves or paired with good ecm-tcm tuning) will increase and improve line pressure characteristics in the 4L60E and 4L80E.

The "Brake" pressure is adjustable on the electronic transmissions. Brake table is in use for engine braking. I would guess that at peak engine braking, the engine might be able to develop 25% of its WOT torque so clutch slippage during engine breaking is not difficult to eliminate. I have monitored transmission slippage as well as converter slippage during engine braking. Transmission slippage is ZERO even with my high compression 383 using the factory brake pressure table. I have a Sonnax line pressure booster kit for the 4L85E but have never installed it. I may install it next time I do the filter and fluid, but it shifts the way I want it to now with just the slight EPC adjustment and tuning. My EPC is bumped up, IIRC 1/4 turn. I did that before I ever installed the transmission.