Mr. Sandog

Okay, I know I'm fat (6,000 lbs +), there's nothing I can do about it, but I still want to have fun every once in a while. I know there are some other 1500 folks (including some Tahoe guys and at least one Suburban guy) who have the same 4L60E/65E + 10-bolt rear combo. Maybe they're not as heavy as me, but they're not 4100 lbs either. Does anyone have hints or tips for keeping stress off the 4L60E/65E + 10-bolt rear combo?

For example, I was looking in the Auto Tranny section at LS1Tech and found out that 4-2 downshifts are extremely hard on the tranny (though I'm not sure why), with 4-3 downshifts wearing down parts also, but not as badly as 4-2 downshifts. WOT 4-2 downshifts are the quickest killer, I read. I didn't know this, and now I am more careful as a result when downshifting.

One thing I know is, when I'm taking off from a stop, I make sure that I've started moving a little bit before I nail it, so that all the components that have slack or play in them (i.e. tranny input shaft, gears, u-joints) have the slack taken out of them and have all components mated before receiving the full torque of the powerplant (thanks grippy).

Also, I know there are some things to watch out for if you have a G80, and perhaps some of these things carry over into if you have an Eaton or an Auburn, but I'm not sure. For example, a question I have with my Eaton LSD, I know it's easy to start spinning tires when I'm turning (i.e. taking off at the bottom of an off-ramp when the light turns green). Is that hard on the differential, or the gears? What do I need to be careful of?

I would think I'm not the only one with this question, so if you have tips or hints, please respond.

dug

iTrader: (10)

What about 4to1 downshifts? I do that a lot

ap2002

iTrader: (8)

white1

iTrader: (5)

I dont think you have anything to worry about with the rear end. Not sure about the tranny though. When the tires are spinning thru a turn, its easier on the diff than when you are going slow, as one tire is trying to go slower than the other, causing the clutches in the Eaton to slip. When the tires are slipping, the clutches are fulley engaged, like when driving in a straight line.

I wonder if that- shift is what killed my tranny??

dug

iTrader: (10)

Its the motors sweet spot from 20-35mph. It goes right to first when floored. Pulls good too.

vanillagorilla

iTrader: (1)

Let off before the shifts. Don't spray through the shifts.

Brake stalling is another way to get all the slack out, if it loads the chassis.

parish8

iTrader: (6)

your screwed

no really, i think the rear will be fine, with a g80 you dont want to stay in it if you are smoking just one wheel. for the tranny i have killed or at least hurt 2 stock trannys MID GEAR. not at the shift or down shift but right in the middle of a gear it would flare up.

mzoomora

iTrader: (31)

I was also going to say that for saving the rear, but it also wears the trans by building more heat. If your rear is marginal it deffinetly helps though, and as long as you dont do it for a long time it isnt too hard on the trans.

Mr. Sandog

I've got a couple more things to do before I can say I've done everything possible, other than going to a different axle and/or tranny setup.

The crate 4L65E went in about 10K miles ago, and the Transgo/Vette/Billet OD servo treatment went in about 5K after that. The only thing I need to do is get the shifting corrected so the 1-2 isn't so harsh. I'm waiting for OCBC to do all the learning on that so he can tell me what to do.

When I went from 3.73's to 4.10's, I replaced the G80 with an Eaton LSD (stock 400 lb springs). I had a T/A cover ready to go, but my panhard bar was in the way so the stock cover had to go back on.

After talking with T/A last week, I found they have a new 1807(A) part that is not only lower in profile, but with the carrier load bolts recessed instead of sticking out. It sounds like overall, it's an inch shorter than the regular 1807. That's next. I may still have some manipulation of the panhard bar, maybe experimenting with some gaskets of varying thickness to move it more rearward, but it looks like I may get a girdle/cover on the 10-bolt after all.

Any more driving tips?

James B.

iTrader: (1)

A 4-2 downshift is a single event: 3-4 clutchpack disengage, and no overrun clutches are active so overrun is allowed. A 3-2 downshift is the most technically complex - band must engage while 3-4 clutch pack disengages. There is even a solenoid dedicated to this downshift.

Back to the original discussion...

The SUVs have so much more weight over the rear end that they cannot be compared to pickups for what holds up and what doesn't. The weight makes traction and it's that combined with torque that tears stuff up.

The 4L60/65-E only has a chance of providing 5-digits of miles service if it is set up never to shift hard. Shifts can be firm but should not jolt under any throttle conditions.

At some point though you'll probably come to the unfortunate realization that any trans based on the 700R4 and any rear end with a ring gear smaller than 9.5" will not let you drive it the way you really want to. Both components are rated far too low to handle the torque a blown motor makes.

It has taken a lot of patience and investment to get my own rig's drivetrain to hold up to the way I drive. I'm lucky to get 10,000 miles out of a set of tires. It would not have been possible with any kind of 10-bolt or anybody's 4L60/65 transmission.