I say convert to a good (with upgraded components) rebuilt E4OD Auto or ZF5 Manual ... Then add the Gear Vendors.

-Enjoy
fh : )_~

 

Thanks everyone! I'll be looking into it more after I throw some money at the old girl for more pressing matters. The joys of owning an old workhorse...

 

New or Old ... You will still make payments!

To a bank or a parts store ...

-Enjoy
fh : )_~

 

yeah,there's no way out of it unfortunately lol.
nice thing about old though,is you just save until you can afford it (thats easier said than done these days lol) without risk of a repo.

 

I'd rather pay to fix it than to pay to fix it while paying to keep it...

 

amen to to fellro well said

 

The truck was paid for in full, thankfully, and it's paid off the repairs we've done to it. It always needs something but hey, it's road legal and working! It needs an overhaul on the electrical to the exterior lights (headlights, backup lights, plow lights), but I got the Buick to drive at night til I can save up for that.

Back to Napa I go!

 

I don't think the lack of a lockup torque converter is that much of a problem. You'd still probably get a nice improvement.

The ZF5 is a nice swap though.... and not that difficult.

If you find a GV, I've got the adapter you'd need to put it on a C6.

The manual switch should be pretty easy to rig too. However, you'd need to be careful because you can burn up the clutches running in overdrive under about 40 mph. That's part of why they use the electronics. The hydraulic pressure for the clutch comes off an input shaft driven pump, so lower speed = low pressure and you'll eventually start slipping the clutch.

 

One way to fix that is to use a pressure switch to cut it out in the event you forget. You just hook it up on the governor test port, have it cut out about 45 mph.

FYI for anyone who is concerned about the torque converter lockup aspect, a non-clutch converter will be .9:1, while a lockup is 1:1. Only concern really is additional heat due to the higher torque load needed. They have been successfully run behind non-lockups for many miles, but a good cooler is a must.

 

i have to say i don't agree with the 40mph rule. GV designed them to be used as a gear splitter, meaning its designed to be used as a half-step between each gear. nothing designed for that would be unable to handle it. its factory controller would have it shift: 1st, 1st-over, 2nd, 2nd-over, 3rd, 3rd-over.
considering that they have this design and such a good reputation, they must be designed to handle low speed use

 

Their own book states to not have it engaged under 40. The clutches are hydraulically applied, the pump is driven by the motion of the vehicle, and 40 is where it is up to operating pressure. Operate it below that and you risk slippage and damage.

The controller actually does not do gear splitting, it only engages after 45. If you want to split gears, you have to do so manually. The controller only knows vehicle ground speed, not what gear the trans is in. If you want it to engage at a different speed, you have to do so manually. When it comes to wiring, there is the solenoid control, the speed sensor, the switch wires(2 switches total), and the power/ground wires, nothing more.

 

all us E40D owners feel this drastic difference at approx 35 mph.it's so much so,its actually commonly confused with another shift/gear.

do yourself a favor first.just go and drive (borrow even rent if you have too) a latter model auto trans truck.you see the rpms drop drastically just when the trans converter locks in 3rd gear at 35 mph.let alone the over drive.
@ $4 per gallon and prices headed north.please research locking converters before you consider spending $ for a GV for a c6.then if you decide you find a good deal or whatever,go at it.but do your wallet a huge favor,just some more research first.i think you'll feel much differently.if not,that's cool.knowledge from the net cost you nothing.

 

GV advertises the OD box can be used as a splitter, but it's not designed for that. The GV box is a rebadged and strengthened Laycock P type overdrive which was originally designed to add an overdrive gear to 60's era British sports cars.

The US Gear dual range is designed to be used as a gear splitter and can be used at any speed.

The GV shifts by moving a cone clutch against spring tension. You need to have enough hydraulic pressure to overcome the spring force and apply the clutch. Say what you will, but I've seen several of these units burnt out from people using them at too low of speeds.

The GV is a nice box if you don't tow too much and just want a higher top end. It's not that heavy duty, doesn't work well as a splitter and doesn't work well with exhaust brakes. The US Gear is a much better unit if you tow IMHO, though it doesn't shift as smoothly.

 

Unfortunately, Last I checked the US Gear units have been shelved and are no longer available!
Nor are parts ...

-Enjoy
fh : )_~