Gearing

[MaxFarmer]

I'm thinkin about changing my gears while I have everything apart.
Right now I am running 35" Firestone Destination MT's.

I will always run a pretty agressive mud grip tire. I'm sure part of my tranny problems is from running this big and aggressive of a tire.

Anyway, since I'm going to be going through the front diff and I know my rear is more a "one wheel wonder" than anything anymore, would now be a good time to put some gears in? I probablly wouldnt go much over 4.11's, what do you guys think?

 

[Mike]

I'm thinking of changing my gears as well but I'm wanting to change it to a higher gear. I don't care to change the tire size anymore so higher would be my solution for toasting 33's at most speeds. Just curious as to why you think your tires size is causing transmission troubles?

 

[MaxFarmer]

Maybe I should try my next transmission before I worry about having more troubles? I just thought the bigger tires is what keeps screwing up my ally. If you think you gotta go the other way than maybe I have the wrong idea? I've been doing some reading since my first post and maybe all I need to do is add some more fluid and some gm addative. I can tell my rear cover seal is leaking a bit and maybe I'm just low enough on oil and that is why they both (rears) arent locking?
I'll know more when I get into the front diff maybe tonight---I swear it took me longer to get it out than it did the tranny!

 

[Mike]

Maybe I should try my next transmission before I worry about having more troubles? I just thought the bigger tires is what keeps screwing up my ally. If you think you gotta go the other way than maybe I have the wrong idea? I've been doing some reading since my first post and maybe all I need to do is add some more fluid and some gm addative. I can tell my rear cover seal is leaking a bit and maybe I'm just low enough on oil and that is why they both (rears) arent locking?
I'll know more when I get into the front diff maybe tonight---I swear it took me longer to get it out than it did the tranny!

Ya, that additive for the rear is very important. It helps with the locking of the gov lock rear. Lube actually causes the clutches to bit and therefore turn the mechanism to lock the rear.

 

[MAXLLY]

Interesting thing i learned in the class. The ECM has a gear ratio entry point when changing tire sizes. As well and unknown to me, the ALLY has a gear ratio in mind as well. Hmmm? What happens when they both match?

I think i heard that the ALLY is pre set with 4:10 and most our trucks come with 3:73, this could certainly affect trans shift points. Anyway it warrants some research, of which i have done none to this point. So beware of possibly a lousy post. The tire size/gear ratio table in the ECM also shows something about changing shift points... Wonder what that is?

Again i haven't looked at it or figured it out. I was paying attention in class!

 

[SIKDMAX]

Remember if you do go to change gears change it in EITHER the speedo calculator OR the parameters table.. if you change it both places I think it was Guy that said itll in effect "double shift" and be bang bang bang bang bang into 5 (or 6) right away.... really messing with the shift points.

 

[MaxFarmer]

Ya, that additive for the rear is very important. It helps with the locking of the gov lock rear. Lube actually causes the clutches to bit and therefore turn the mechanism to lock the rear.

My oil level on the rear diff was maybe just a little overfull. I drained it and then took the cover off and the oil level was right at the middle of the fill plug.

What I did find is that I am missing a bunch of random teeth on the outer ring of the Locking Cam. It looks like the clutch steels go over theese teeth and run the cam against the LH (looking at from rear) gear. (Without doing any searching yet) Can the internals of the rear diff be replaced or do you have to buy a whole new diff? It looks like there may be clutch packs inside as well, are these replaceable?

 

[MaxFarmer]

OH, has anyone tried messin with the locker governor to help with locking up better? :devil:

 

[MaxFarmer]

I'm sure you guys can see the broken off teeth to the lower left of the posi gear.

The end of what I think is the governor seems to be worn out on these teeth.

 

[MaxFarmer]

Nobody had this happen before?

 

[Ben46a]

Put the dodge torsen diff in it. The gov bombs dont take abuse or overhauling well.

 

[Lonnie]

I have seen tons of problems with gov-locks in nearly every appplication that they were installed. I do not know why GM/anyone insists on still using them.

Unfortunately that little pencil sized shaft must limit rotation of the outer gear to cause the clutches to lock. The quantity of internal clutches is limited & can easily be overcome if 1 wheel has significantly more traction than the other.

My friend blew out his (04 lly with 9K miles) making a turn in his yard next to his driveway. 1 tire was on grass & the other blacktop. It spun slightly & did exactly what you show.

I used to explode 12 bolt versions (4 over a 3 year period, at least I got used ones cheap) of these in my own 1/2 ton pickup with a little 350 motor. Given the opportunity, use a different posi unit.

Lonnie

 

[MaxFarmer]

Given the opportunity, use a different posi unit.

Lonnie

Do you reccommend Torsen also Lonnie or what were you thinking? What are you putting in your truck?

 

[Lonnie]

Torsens are good units, but I personally have no experience with the AAM 11.5.

I will be using the 14 bolt 10.5" rear as that was the 3/4 & 1 ton rear used in my series of truck. In this case, the Detroit Locker is the way to go. They clunk a little, but are virtually indestructable.

Unfortunately, I do not think the locker is available for the 11.5. GM coupled the strongest pickup truck axle with the worst posi ever made.

Lonnie

 

[MaxFarmer]

Well, based off internet prices at Randy's:

GM Gov-Loc posi for AAM 11.5"---$912.80
Yukon 11.5" Chrysler Helical Gear type (Like TT) Posi--$648.65

That about solves it for me. The Yukon is the same as Torsen right?
Ring and pinons for gears run $367/set (342's or 411's)

 

[MaxFarmer]

Oh, and front diff ring and pinons $302 for 3.42's, $256.50 for 4.11's.

I'm having a tough time deciding which way I want to go with gearing. If I was strictly 1/4 mile racing I would go 4.11's. I do more mud racing and would like to try truck pulling which means I should go to 3.42's. But most of the time I just drive it to bowling, get drunk and break it anyways. Maybe I should just stay stock......

 

[MaxFarmer]

Skipping gears for now....
BUT, does anyone know if the Dodge/aam/torsen rear ends need the special ani-slip addative like the GM gov-loc's do? I'm ready to put the cover on but I need to know wether I need to pick up that expensive GM addative or not when I'm in town tomorrow.

 

[MaxPowerLB7]

I think you've got the ratios mixed up 3.42s would give you higher gears and a higher top speed. Whereas the 4.11 would be lower gearing and a lower top speed potential...

I don't know s**t about rearends though, other then swapping a couple out...

 

[MaxFarmer]

I drag race in high, mud race in low. Right now low is too quick (esp. 1st gear) so I would go to 3.42 to lengthen it out a little in low range. I am going to try the 2nd gear start approach before I do gears now. That is where I always gained on people---in 2nd gear. I just couldnt spool enough in the mud, all the gassers get a huge jump on me.

 

[nar]

I'm going to guess that's how mine looks inside, or worse...