1980 Pontiac LeMans Station Wagon - G-T-faux (stuck with it, and can't shake it... like a bad case of herpes)

[motorheadmike]

The 4L80E is a great unit, nearly indestructible with small upgrades. But your list shows what even a good used trans will cost, a lot. And the dam trans is huge, as your measurements show, good luck fitting it in and show us your solution. I will probably throw a BOP TH400 short tail at my 70S to start, there is no such thing as a strong, cheap OD trans install. That means a yoke change and move the cross member back, Transgo with dual feed and a $300 converter. Problem is any OD that fits easily, the 2004R or 700R4/4L60-70E needs about $1500 worth of internal upgrades, just parts, not labour plus a good converter which isn't cheap. The 4L80E should allow you piece of mind but still costs an arm and a leg and a big install headache.

And that doesn't include the $800 Canadian I spent on the used transmission! All-in this swap is going to cost me about $3000 to do it well.

It would be great if I could offset the costs a bit by selling some big ticket items, but post-Christmas is a horrible time to achieve stuff like that. Plus, it isn't worth dealing with the tire-kickers and time-wasters. Consequently, it must be done incrementally (I am still paying off the damn built 4L70E in the TBSS, FFS) - I expect to have the wagon back up and running by April/May.

All that said, I enjoy the process of creating solutions to problems that I have created for myself. I can't leave well enough alone. 😉

 

[olds307 and 403]

Mike, those trans go for $600 to $1000 used in Saskatchewan as well. I figure at minimum without a controller around minimum $2000 to get one is my 70S. Compare that to $600 for a TH400, it can be tough to justify an extra $1500.

 

[motorheadmike]

Mike, those trans go for $600 to $1000 used in Saskatchewan as well. I figure at minimum without a controller around minimum $2000 to get one is my 70S. Compare that to $600 for a TH400, it can be tough to justify an extra $1500.

Except having OD is a big deal in a family car... buzzing along at 3500rpm is not good for anyone. I need to get the A/C sorted out for Summer so we can actually road trip this thing as a family - the whole reason it was built.

I did the TH400 thing in my Turbo Buick, it worked okay since it had 3.08 gears.

 

[motorheadmike]

Mocking it up. I have designed it with a fair amount of room to go up, a huge issue with the G-Force unit.

 

[motorheadmike]

Fabrication. Frustration. Triangulation. Satisfaction.

 

[TURNA]

You forgot snapation!

 

[olds307 and 403]

Nice work, an I agree on driving around at 3500 RPM gets old fast. Heck, I am planning 29" tall tires to drop the RPM down 200 RPM, from 2400 RPM at 100 km/hr to 2200 RPM. Of course I am planning on close to 500 ft/lbs of torque as well to live with crappy 2.78 gears.

 

[motorheadmike]

Nice work, an I agree on driving around at 3500 RPM gets old fast. Heck, I am planning 29" tall tires to drop the RPM down 200 RPM, from 2400 RPM at 100 km/hr to 2200 RPM. Of course I am planning on close to 500 ft/lbs of torque as well to live with crappy 2.78 gears.

Thanks. The wagon's tires are a bit below 28", and it has 3.73s - so I have little choice in the type of transmission. The funny thing is with the lower first gear and added mass (static and dynamic) - I have essentially made the car "less quick". Which is why I am looking to a much higher stall converter to regain/improve the rate of acceleration.

 

[olds307 and 403]

Much less first gear, I am thinking 2500 stall minimum as well with the same 2.48 first gear and the crappier .75 vs .70 overdrive are draw backs. At least the 4L80E gives a massive dose of reliability under big power.

 

[motorheadmike]

Added some more bracing and material to key areas to reduce the potential for flex or twist. I boxed in the "frame extensions" and added some material to the mounting flanges (witness marks were shallow). Braced up the Z'd (read zee-duhd, even in Canada) arms with some 3/16" plate. And lastly, added some 3/8" rod to one side of the exhaust cut outs (may do the other side after I trial it).

It is still amazingly light compared to the G-Force unit, and comparable to the stocker.

Flux core spatter cleaning pending - or just cake it in POR-15 to hide all of my sins.