14FF questions, including G80. swaps and functions?

[Rocket Surgeon]

I have two trucks, both 8 lug K2500 5.7 NV4500s with 241C with 14FF 3.73 axle ratios.
One has the G80, the other does not. I think all else on the axle is the same.
Reminder that these are 14 bolt Full Float; we are not speaking about the gov-bomb in the 10 bolt axles.

I have located a k2500 rear axle of the same vintage, but with a different ratio 4.11.
I am not interested in changing up ratios.
Sorry, I forgot to state it is a G80 4.11


questions:
1) Both G80 axles are pretty much locked from a stand still. They are locked the moment you try to move them. I presume this is normal in the 14FF?

2)Is a used but apparently good 14FF gov lock worthwhile to utilize, vs aftermarket parts?

3)can I change the pumpkin into my open 3.73 ratio diff, using my 3.73 ring on the donor pumpkin?

4)I am aware that the G80 requires a non slip additive fluid... does that include the 14FF, and/or all g80 variations on all gmt400 possible axles?


5) I still have not seen a good definitive info on one other thing I would be ok with, which is a compatible gmt800 axle or equivalent to what I have currently. Disc brakes would be nice. But the spring and shock mounts may need moved?

6) I do not like the aftermarket disc brake conversions that do not support the caliper, has anyone looked at gmt800 axle flanges that support a caliper to see if they can be fitted to a gmt400 axle?



I have some other thoughts to go on:
If I was to change the ratios, I would prefer to go to a smaller number like 3.43 for better highway efficiency. I feel I have enough low gear.

Also as a manual, I do not have to worry about shift tables. I shift were I need.

I also have a pending mod I would like to accomplish. Install a cut off switch to front diff actuator to enable 2wd low, giving the capability of real low gear with easy turning and control. It is easier to park when inches are not there to spare in low gear.

Thanks for your knowledge.

 

[someotherguy]

Locked from a standstill? You mean no load, turned by hand, both axles turn, and the same direction? Beats me. It's supposed to take a slight difference to engage the unit, IIRC 100 rpm or so. This may not be true in a no load situation, so I'll let someone else answer that one.

The carrier for the 3.73 gears is probably the same for the 4.10's. You can probably check on Randy's Ring & Pinion site to confirm this.

Same regular fluid used in all incarnations of the Gov-Loc. No additive.

It's not a terrible unit, for a factory low-bid "locker" - it's just weak in the 10 bolt variety.

Different gearing like a 3.42? Not sure that's out there in OEM form for the 10.5" FF - probably available aftermarket, though. 3.42's were OEM in some 9.5" SF units.

Richard

 

[PWC Repair]

1...Normal. There's still a clutch pack inside. While jacked up they will both rotate the same direction and if you hold one still the other will have noticeable resistance trying to rotate BECAUSE of the clutches. Then with wheel speed differential the engagement mechanism LOCKS both sides together.

2...Yes, normally a good unit. They are much heavier duty than the 10 bolt versions. A lot of guys off-road them without issues.

3...As far as I know, ALL the 14 bolt corporate stuff will interchange AS LONG AS..FF stays with FF and SF stays with SF. 4.11 and numerically lower use the same carrier.

4...ANY clutch type posi supposedly requires an additive. I've only run synthetic fluid WITHOUT additive and never had problems.

5...Can't help any there

6...Haven't lookad at any but when I convert on my dually I plan on just using the aftermarket brackets and welding my own support plates to those.

 

[someotherguy]

4...ANY clutch type posi supposedly requires an additive. I've only run synthetic fluid WITHOUT additive and never had problems.

Not a posi, and while one can certainly argue it has clutches, GM has specifically stated to not use friction additives in the gear lube for an Eaton Gov-Loc unit. There is a TSB that has been widely circulated, posted, and quoted many times throughout the years. Improper operation of the unit can (and often will) result.

Richard

 

[Rocket Surgeon]

Thanks so far!

I forgot a question... Whom makes this locker?

I saw a mention stating that it is an Eaton, but that's not proof.

Also that these axles were not made by GM but by someone who also made Dodge axles...


and yes, locked from a standstill.

 

[454cid]

Thanks so far!

I forgot a question... Whom makes this locker?

Eaton. There are videos on Youtube showing details about it. I like the very old one, filmed at the Eaton Proving Grounds in Marshal, MI.... back in the early Squarebody days.

Also that these axles were not made by GM but by someone who also made Dodge axles...

American Axle & Manufacturing (AAM). It was part of GM, but purchased by a former Chrylser executive, and investors. Later AAM started making axles fro Chrysler/Dodge.

They should not be locked from a standstill. I've never owned one. It could be that there is enough resistance if turned by hand, that both sides turn. In operation there has to be about 100 rpm differance for it too lock. That's the whole idea is that it's basically open, until needed.

 

[Rocket Surgeon]

Eaton. There are videos on Youtube showing details about it. I like the very old one, filmed at the Eaton Proving Grounds in Marshal, MI.... back in the early Squarebody days.

This one?

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[Schurkey]

The Gov-Lock in my 14-bolt semi-float allows one axle to spin with a flick of the wrist. No resistance at all. Unless you spin fast enough to engage the "lock", and then there's no turning it.

 

[PWC Repair]

I've found that to be the case with regularly driven vehicles. The ones I've come across in junkyards or sitting for years have noticeable resistance. I've actually taken the G80 apart and modified them so they don't tear themselves to bits by the SLAMMing lockup. I've also modified the weight mechanisms to hold lockup to whatever speed you want. I posted all that with pics on the S10 forum YEARS ago.

 

[454cid]

This one?

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Could be or maybe edited with some of the same footage. I thought it was a bit older than early 80s, but I guess not.