4L80E too much transmission?
12-22-2015, 08:52 PM
#21
12-23-2015, 12:10 AM
#22
TECH Enthusiast
Spicer 1350 solids in mine, but my 1/2 ton already had a 4L80E sized U-joints, removed the 60E yoke, slight cut, reweld, balance, 4L80E yoke and down the road.
12-23-2015, 05:37 AM
#23
I've had pretty decent/hard use of my 60e for the past 2 years. For the better part of 18months, I've had TM removed completely.
Now, I wouldn't suggest doing that without first "tuning" the FMC table(s) and modifying the line pressures a bit.
I know what you're thinking, going all out on the line pressures...no, not at all.
I for everyday driving, I command 90lbs starting at 300ft-lb of torque. In the performance table, I command 94lbs across the board and lower shift times. I think I am running .250 shift times right now.
The FMC table is really where the "feel" of the shift comes from. I've got a nice, firm, positive shift.
The problem with the stock FMC table is that at 100% throttle, GM is bleeding off the pressure.
(knowledge gleaned from jimmyblue at ls1tech)
Now, I wouldn't suggest doing that without first "tuning" the FMC table(s) and modifying the line pressures a bit.
I know what you're thinking, going all out on the line pressures...no, not at all.
I for everyday driving, I command 90lbs starting at 300ft-lb of torque. In the performance table, I command 94lbs across the board and lower shift times. I think I am running .250 shift times right now.
The FMC table is really where the "feel" of the shift comes from. I've got a nice, firm, positive shift.
The problem with the stock FMC table is that at 100% throttle, GM is bleeding off the pressure.
(knowledge gleaned from jimmyblue at ls1tech)
12-23-2015, 08:38 AM
#24
I've blown through two builds of my 60e behind a built 383 stroker. Its a daily driver and I honestly don't have the best restraint on the pedal so the 80e swap needs to be my next mod. I know I'll sacrifice a little weight in the ends but it's worth saving the $1,200 bucks every 18 months or so to rebuild the weaker tranny. Besides, I'll even out the weight issue by getting rid of the rear bumper for a rollpan and a few other weight related tweeks. Just dropping the spare alone saves the diff between the 60e and 80e in the short term.
12-24-2015, 08:51 AM
#25
Thanks, glad to be of help.
I'm not familiar enough with the OEM specifications of GMT800 propeller shafts to say whether or not it would be feasible to modify the stock shaft. There are two criteria - in order to install a 1350 yoke at the transmission end of it the existing 3R yoke has to be cut off, so there needs to be enough length remaining of what's left. The other factor is material thickness and whether or not your fab shop is going to comfortable welding the OEM material and rebalancing it. I'm only familiar with local shops around me (Riverside, CA) and always use Inland Empire Driveline in Corona. Almost any driveline shop can make what you need though, they're nothing special.
As to the differences I was talking about between the fixed-yoke and slip-yoke versions of 480-E, here and example that shows the different types of shafts compatible with each. Note the slipyoke on the aluminim shaft pictured is for a Gear Vendors overdrive and is short, 4L80-E slipyokes are a lot longer.
I'm not familiar enough with the OEM specifications of GMT800 propeller shafts to say whether or not it would be feasible to modify the stock shaft. There are two criteria - in order to install a 1350 yoke at the transmission end of it the existing 3R yoke has to be cut off, so there needs to be enough length remaining of what's left. The other factor is material thickness and whether or not your fab shop is going to comfortable welding the OEM material and rebalancing it. I'm only familiar with local shops around me (Riverside, CA) and always use Inland Empire Driveline in Corona. Almost any driveline shop can make what you need though, they're nothing special.
As to the differences I was talking about between the fixed-yoke and slip-yoke versions of 480-E, here and example that shows the different types of shafts compatible with each. Note the slipyoke on the aluminim shaft pictured is for a Gear Vendors overdrive and is short, 4L80-E slipyokes are a lot longer.
I'll have to get some measurements to get the exact length that the driveshaft needs to be cut down. It will be cut on a lathe.
I would weld it after cutting it. I'm a weldor by trade with a little experience under my belt
If there comes a time that I am not comfortable with what's happening. I can call the shop who built my rear-end and drop it off.
They would probably know the difference in yokes you are talking about, correct? I'm going to send them an e-mail.
Picture/Link doesn't work
Thanks again James, I appreciate your time and info
Hahaha, I was thinking the same thing.
12-24-2015, 06:26 PM
#28
Launching!
Join Date: Sep 2013
Location: Lutz,FL (its called 'Lootz")
Posts: 208
Likes: 0
Received 1 Like
on
1 Post
You can have a shaft built for $300-400 and it's worth the money for piece of mind. I have a NA 5.3(nitrous currently disconnected) and I swapped to a built 4l80. I do have other plans in the future, but I have zero trans worries and I like the split from 1st to 2nd gear so much better. No more lugging after the shift. My mpg have stayed within 1-2 mpg difference. I will never own another 60e in a truck again for the shift alone. Also I drove for 2 years with all torque management removed,3200 stall, factory external trans cooler,bolt ons and 100 shot. Thought I broke my 60e, found out it was a mouse under the engine fuse box eating wires.
12-24-2015, 06:48 PM
#30
My swapping gmt800 driveshaft was modded. Then again it didn't have a spot of rust on it. My old driveshaft is rusted to crap.