Stock 350 3/4 ton transmission options

[Sean Buick 76]

I paid a guy to create me a little trans controller about 15 years ago for a 4L80E. It was setup to work with a steering wheel paddle shifter arrangement and it gave me manually operated up and down shifts at my fingertips. I think he charged me about $250, but this was back before the controllers became common and lower cost. It was in a twin turbo car that was a handful and being able to shift it with the paddles was very helpful!

 

[Sean Buick 76]

By the way the 1991-1993 6.5L diesel trucks that used the 4L80E transmission had a stand alone transmission controller. That’s what you want to poach from!

 

[b454rat]

By the way the 1991-1993 6.5L diesel trucks that used the 4L80E transmission had a stand alone transmission controller. That’s what you want to poach from!

I had a 92 Blazer way back when, wanted to swap in a 454/4L80. Back when the 454SS site was around, I was on there looking for info. For what ever reason, using the stand alone won't lock up the converter. I don't know the details, but guess it's been tried, but couldn't get it to work.

You can get a basic controller from USshift, wanna say it's $350 but haven't looked in a long time. I don't know if the 4L80 trucks used the 7747 ECM, but would need parts truck from 91-94, not a very long span for parts. IMO, swap column/pedals, use the stand alone and be done. T-case would swap over too.

 

[Sean Buick 76]

I had a 92 Blazer way back when, wanted to swap in a 454/4L80. Back when the 454SS site was around, I was on there looking for info. For what ever reason, using the stand alone won't lock up the converter. I don't know the details, but guess it's been tried, but couldn't get it to work.

You can get a basic controller from USshift, wanna say it's $350 but haven't looked in a long time. I don't know if the 4L80 trucks used the 7747 ECM, but would need parts truck from 91-94, not a very long span for parts. IMO, swap column/pedals, use the stand alone and be done. T-case would swap over too.

Good info. All that’s needed to lockup the converter is a toggle switch really. My 91 K2500 back in the day wasn’t locking up so I added a fused wire to the trans with an in line toggle switch. I used it for years like that, although it was likely caused by the in line brake switch switch that GM added to shut it off instantly when braking. Or a person can use a TCI or B&M lockup kit. I just didn’t mind using the toggle switch to lock it up on the highway.

 

[Erik the Awful]

If your truck is a 2500 with a stock 4-speed manual, I'd keep it as-is. That's a unicorn.

If your highway rpm is too high, put some taller gears in the back or some larger tires.

If you're dead set on a transmission swap you'll need a cluster and you'll want the wider automatic transmission brake pedal. You'll also need to fabricate a plug for the clutch master mounting hole in the firewall.

 

[99xcss4]

By the way the 1991-1993 6.5L diesel trucks that used the 4L80E transmission had a stand alone transmission controller. That’s what you want to poach from!

yes that is right but there was no 6.5 till some time in 92 91 was still the 6.2 92 started with 6.2 most likely to use them up like you were saying that the most likely did that with the th400s that made it to 91 by the way what month was your 91 made in

 

[99xcss4]

I do not know why gm thought it was okay but seems that most if not all of the 6.2 diesels were paired with the 700r4 they made between 130-160 horsepower and between 240-275 ftlbs of torque I think the th400 would have done better I do not know if any of them were ever paired with a manual

 

[L31MaxExpress]

dosent he need a column shifter unless he puts in a aftermarket floor shifter that is why I said swap or mod the column

Brain fart. Even after I posted about the SM465 I got busy and went back to thinking it was a TH400 truck.

 

[L31MaxExpress]

I do not know why gm thought it was okay but seems that most if not all of the 6.2 diesels were paired with the 700r4 they made between 130-160 horsepower and between 240-275 ftlbs of torque I think the th400 would have done better I do not know if any of them were ever paired with a manual

Alot of 6.5Ls were paired to the 4L60E as well. They used the same transmission controller as the 4L80E but with a different calibration chip.

 

[L31MaxExpress]

By the way the 1991-1993 6.5L diesel trucks that used the 4L80E transmission had a stand alone transmission controller. That’s what you want to poach from!

Fullsize G-vans with diesels had a version for both the 4L60E and 4L80E from 91-1996. GM only used the 4L80E above 7,400 lbs GVW in the G-vans. The 6.5L G20 and the lighter duty 7,400 lbs G30 had a 4L60E in them behind a naturally aspirated 6.5L.