'71 Chev pick up 4L60E swap.

[Six_Shooter]

Over the last few days I've been working on a TH350 to 4L60E swap in my grandfather's '71 Chev Pro Street (looking) truck.

This truck has an '81 F-body front clip, with a SBC. Most people are able to, with tis front clip, slide the stock crossmember towards the rear and drill new holes. I'm not so lucky, since the floor is pretty low and very close to the tranny, the crossmember did not swoop down far enough, to be able to use it, so out comes the grinders, and welders.

It should be pretty much done except for the driveshaft tomorrow. :)

[Six_Shooter]

Well, had the driveshaft shortened, installed, everything is back together, with two small hitches. The lines are leaking at the tranny for some reason, and there doesn't appear to be a VSS signal that the PCM is using or can see. I think I may see what I need to change in the bin to get it to recognize the VSS I am using.

Should have it completed by tomorrow if all goes well. :)

[EagleMark]

I want to see a picture with the tires smoken ay! :mrgreen:

[Six_Shooter]

Well, didn't get everything done, but the lines no longer leak.

I just need to program an EEPROM to test what I think it needs, then it should be good to go. :D

[Lucky]

Does this tranny have a lower 1st gear ratio than the th350 ?

[Six_Shooter]

It does, in fact all but OD and 3rd are lower (TH350 doessn't have OD, so does that even count? lol)

http://www.oldengine.org/unfaq/leadfoot/trans.htm

[EagleMark]

I am not up on tranny knowledge, but I think the 4L60E is the same trans as a 700R4 with electronic updates? But the 4L80E is a differant trans? Help clear me up...

I know my 700R4 has a way low first gear compared to a turbo 350 I have driven.

[Six_Shooter]

Yes, the 4L60E is a newer version of the 700R4, that is electronically controlled.

The 4L80E is a different trans.

BTW, I EFFING hate this truck...

Today the fuel pump died, leaving me stranded perpendicular to the road, as I was attempting to turn around. This pump has less than 30 miles on it.

This truck has been together for about 12 years and we have hardly driven it since it has never ran right. I think it's cursed.

[EagleMark]

I hate when that happens!

But thanks for the trans lesson! :mrgreen:

[Six_Shooter]

After some more research it seems the '7427 needs to see a 40 ppr signal to control the tranny properly.

Arg, now to find a somewhat rear VSS, that also has the cable drive or fabricate a reluctor to attach to the diff.

[Lucky]

The Rover stranded me in the middle of a major intersection the other day - Fairview and West st - also the fuel pump. Part of the joy of modifying vehicles it seems. Everyone was very helpful about honking their horns at me while I pushed the truck out of the street by myself :?

[Six_Shooter]

The Rover stranded me in the middle of a major intersection the other day - Fairview and West st - also the fuel pump. Part of the joy of modifying vehicles it seems. Everyone was very helpful about honking their horns at me while I pushed the truck out of the street by myself :?

I had a bunch of people drive past, which doesn't really bother me, but it was pretty clear that the lady that was in the heating business had seen that I had stalled and was pushing the truck around by myself, when she looked out the window and said, "Oh, you got it pushed out of the way." :roll:

[buddrow]

4L80E is based on the TH400 with an over-running clutch, an overdrive clutch, and an overdrive gearset added. It is beefier and bulkier than the 4L60E, requires a TH400 style driveshaft yoke, and slightly different shift solenoid operation than the 4L60E.
The 4L60E is i deed based on the TH700R4 with electronic controls added.

[greggbruceauto]

4L80E is based on the TH400 with an over-running clutch, an overdrive clutch, and an overdrive gearset added. It is beefier and bulkier than the 4L60E, requires a TH400 style driveshaft yoke, and slightly different shift solenoid operation than the 4L60E.
The 4L60E is i deed based on the TH700R4 with electronic controls added.

actually, if you lay the planets for both of those side by side, you will find that the 700/4l60 planets have physically bigger gears --- but the apply components for the 400/4l80 are bigger ---- plus the 4l80e does have the EXTRA planet in front for overdrive as stated above, so it doesn't mind if you tow in overdrive. The 700/4l60 uses the rear planet for overdrive, and if overloaded, will overheat and turn pretty colors of blue/purple/black as they are melting away......