ZD1

After much deliberation I decided on a set of 3.73s. which meant when I was shopping for a dana 44, i could go with a cheaper 3.07 set and let the retailers keep their "higlhly valued" 3.45s. With th ZF-6 in .50/6th gear im doing about 77 MPH...good enough. (for those of you that don't know im changing from a D36 2.49 gear set)

This is more of blog…but you’re more than welcome to comment ask questions. I always seem to need to go back 3-5 years and look at what I did. It’s also late, so English skills may not be reticent.


This is what you need to for a gear change
1) Have two separate shops recommended by friend(s) refuse the work

2) Handy 40” plumbers wrench, 15 hammer/large brass punch, access to 15-20 ton press, .0005” calipers, dial gauge, pry bars, socket set, 1-5/16” socket (why? I dunno), block of wood and set up bearings

3) Patience and multiple sources of information


Key points I have learned the hard way:
1) Measure the difference between the compressed width of setup bearings versus your live bearings. My carrier bearing were close .0010 narrower and .0005 narrower. But the live pinion bearing was .006” narrower. So I needed to compensate for that in the final build up.

2) I didn’t take into consideration the crush sleeve impact. The crush sleeve you use once, but it took out about 0.003”… I was lucky in that I was over shooting my pinion into the ring gear byy .004”…Pinion depth came out OK in the end.

3) Crush sleeves suck…300-400 lb-ft needed…confirmed. At that level you don’t even bother with a torque wrench. On the final setup though I cranked once to many times, but it turned out ok. With a crush sleeve you are trying to get to a torsional preload on the pinion bearings. I went from near zero pre-load to 25 lb-in in ¾ turn (six pulls on a 36” breaker bar with a plumber’s wrench holding the yoke). Goal is 12-20 per Yukon. Once I rotated the pinion a few times and let the royal purple work, preload decreased to 8-16 in-lbs. I don’t have a fancy pinion yoke preload checker, just calibrated my finger.

4) ring gear bolts are finicky. Torque is 55-lbs and they cannot take more

5) Race oriented bearings have more polishing, so they are bound to be narrower that napa or stock.


Good advice I remembered:
1) Label and record everything as you disassemble the case

2) There’s no shortcut for torqueing everything down when taking measurement (2004, it took me 30 tries before I leanrt that)

3) buy a cheap set of bearings (two carrier and the larger “head” pinion bearing) and auger them out. The pinion bearing needs it bearing’s ID opened up to fit on the pinion and the OD of the pinion head bearing race needs filed to easily set in the case.

4) Put at most resistance as you can on the wheel output of the differential to create a good pattern

Conflicting sources for setup
I used three different guides for setting up the gears. Yukon instructions (generic for all their gear sets), a jeep DIY site-pirate4x4, and a PDF I downloaded from rsgear.com. They of course conflicted. Here’s why. If you don’t keep the Backlash the same each time, you’ll have adjust the pinion gear one way. If you keep the BL the same and/or tight, you’ll have adjust the pinion gear the opposite way.
Yukon basically says to ignore the pattern heel or toe and just get pattern to show the pinion is deep enough, then set backlash. Their instruction say that you’ll go nuts trying to set the perfect pattern.
Both the jeep sites (Dana 44 are everywhere) rsgear push for the centered pattern on the drive side and slightly toe-ish for the coast/reverse side. They of course differ on what to do when a certain pattern shows up.


The disassembly:
I actually did not totally disassemble everything until I was ready to finalize the setup. The stock pinion head bearing had 040 shim under there. It just so happens that my setup bearing (napa timkin bearing) was also 040. The stock pinion was marked 787 and +1. The Yukon pion had OD OL etched in…useless. It took me about 9-10 tries to hone in on it. The final setup installed was +050 with the narrower bearing.

For some reason the Ratech kit I got from Summit had a nicked pinion nut, and either I lost the carrier shims or they were never in the box. As a self-proclaimed mad scientist, I can’t really ignore that I may have lost the shims. Either way check your kit.

I took extra time to pressure wash and drill-wire brush clean the case. Then painted it with silve caliper paint.

Yet again, I did not rebuild the posi clutches (wonder if that’s going to bite me later on?)


The Assembly attempts: in all 15 tries to get a final pinion setup. That’s where I am right now. I have only the original carrier shims, so I’m waiting to get new replacements to finalize the carrier.

1) For the pinion, In just torque the pinion nut until there was 30-50 in-lb of resistance. If Yukon had sent me a pinion that used shims for the preload, I would’ve had to find the right shim load-out and torque every time to 150 lb-fts(?). I’d rather have the shims setup so I don’t have to guess the shims load-out for the crush-sleeve.

2) I keep my BL between 0.000 and .008, or I wouldn’t even bother with a getting a pattern. I’m still not sure how I got a BL at 000 and could still turn the pinion? I’ll probably intentionally overshoot the BL at 003-005 versus the allowable 006 – 0012. My intention is to keep it tight so it can handle more power (more resistance), but more importantly keep the BL tight as the ring and pinion breaks in. Also, “my experience” is that the difference between setup bearings and real-final bearings necessitate a tighter goal when going “final”.

DanZ51

Interesting read. I'm contemplating swapping gears this winter. Currently I have 3.54 in my Dana 44 that Florida Caliper installed years ago. Last year I swapped the old DNE 4+3 to a T56, so my overdrive gears went from .67 for the 4+3 to .74 (5th) and .50 (6th). I crunched some numbers and now looking at 4.11 to make 6th usable and the rest a lot more fun.

Funny, I thought all Dana 44HD were set up with shims and crush sleeves weren't even an option. I see you didn't list a bearing splitter, is that why you used "set up" bearings or is it more of a personal preference?

WVZR-1

A couple comments:

Most aftermarket gear sets use crush-sleeve/collar, nearly ALL! Even late production C4's used a crush-sleeve/collar. That's not widely known but if someone has disassembled a known later build yes it will have a 2 3/4" crush-sleeve/collar.

I believe if I had a known good low-mile 3.54 build I'd consider selling it assembled. The used gears are worth?

If your 4.10 was to be a final build for you I'd build another. If you're interested in NOS housing, new Dana brand 4.10, new Dana carrier, NOS short axles and a kit I should be ale to help you. I've an NOS bat-wing if you were interested in that also.

----------------------------------------------------

OP - It's an interesting and sometimes difficult read but it seems you've satisfied yourself with procedures. I don't understand why you've not done the clutch pack and it sounds as if your still waiting parts so I'd go ahead and do it. The pinion washers under the pinion gears in the differential need checked when you slip them out and it's best to REPLACE. A snug clutch pack, snug fit of the differential pinions and differential side gears is important for longer life! The snap rings on the short axle inside the differential are also selectve.

rklessdriver

IF your going to go thru the trouble of a new gear and brgs.... Rebuilding the Trac Lok should be a given....

There is a pretty good write up on another board about rebuilding and inspection of the D44 Trac Lok....

Google : "Dana 44 Trac Lock rebuild Tech Thread"

Will

Zip Corvettes

You did not say what you were doing with this car so hear me out on this. The BL really depends on what you are going to be doing with it. If you are going to be on the street then try and shoot for .010, this will give a good oil film on the gear, it will keep heat down and it will be quiet. However at the end of the day you need to be where you have the best pattern and that will also dictate your BL setting. Don't listen what they are saying about achieving the perfect pattern, you need to have a good solid pattern on the drive and coast side period. As far as they way you are making your setup bearings, they are going to give you a false reading on your setup. We go through allot of setup bearings, but they have to be honed to where there is about a .0005 press so that the bearing cannot "rock" on the pinion or on the carrier. You can't do it by hand. Do not take the carrier apart, you have to have the right tools to the the clutchs spread in order to get the spider gear washers in place. Just take your time, you do not want to blow a D44 up as they are very expensive to replace. Also make sure the carrier bearing are completely seated in the housing before you install the main caps, if not you can crack the main cap and the housing is done after that. Also you need to make sure that once your setup is done, don't forget you need to have a preload on the carrier.

WVZR-1

That's a good read and the BL comments for a street gear set-up is worth people paying attention to!

I don't understand mentioning to someone who has just spent $400+ dollars to NOT worry about the clutch pack and the pinion washers. In the next sentence you mention it's a very expensive rear to replace just be careful. While the correct tools make the clutch pack and differential assembly much easier it can be accomplished with-out.

I believe that 3 of maybe the last 5 failures I've seen have been the failure of the differential pinions and then they take out the ring gear and pinion. One of those actually exited through the bottom of the housing. The pin and the differential case should be inspected very closely.

Years ago our pinion washers were replaced every season. Not a super 44 but a "differential is a differential" I guess you could say.

mtwoolford

I would underwrite the costs of labor by pulling the batwing / differential, seperating the differential and then sending the differential to someone who (1) will do the work; and (2) does it all the time.

I would then reinstall the differential to the batwing and reinstall the unit myself.

JMO

WVZR-1

For most that is probably a "wise" decision !

ZD1

Unfortunately, the two "race" places in town refused the work. I probably forgot to mention that I "knew" somebody to them.

Final BL is tighter than I'd like, but it is what it is. Patterns are good and solid on the drive side, coast side is more toe per yukon. Carrier preload was with an additional 006 (7 whacks). I fully expect the breakin period to be quite interesting as "settling" will occur [right word]

I use the car for everything (except camping...didn’t workout last time); which requires comprises in all things. I don't expect 10's as my 60 foot time will never be good enough, as I choose to build more for road course than drag. The other thing with drag racing as well is that the shock loads re going to tear everything up…especially with a motor that should be pushing 600 ft-lbs. HP dyno wars will always be defunct as my cam is small for sneakiness and emissions (242/244). Autocross will always be limited since she's a modified and gold platted brick (my class is for full up 2000lbs race cars). Road courses are limited as she is for street as well (weight, A/C, Radio). All this and I still expect to drive across country as needed.

I am a mad scientist and I know it.

as of today the diff and suspension is all in. Royal Purple plus limited slip addictive has been added. Just to piiss someone off here i resued my half shaft u-joints.

D44 drive shaft measured .75 shorter that the D36 drive shaft...kinda waste of time and money. Shouldve just cut the D36 that I know is balanced and got to go. New U-joints here.

ZD1

040 was the stock pinion shim
Final bearing measured 1041 (NAPA checking measured 1047)
Final pinon shim stack 050 (040 plus 010)

RGS bearing measured 8425: (NAPA checking measured 844)
NGS bearing measured 843: (NAPA checking bearing measured 843)

Zero pre-load (motivated drop in) total carrier bearing stack was 094, would not install with 100 total.

Total final pre-loaded carrier stack was 97
RGS had 40 thou shims (only the 28 shim was reused from previous go)
NGS had 57 thou shims (only one 12 and the 3 were reused)

final bl measure 004
see ya in 5 years