What are you guys setting up a Dana 60 pinion bearing preload at? I'm finding specs ranging from around 15 to near 40in-lbs with new bearings. Also, do you check with the carrier in place or just the pinion? I'll have a spool with 4.30 gear.

15-17, but I’m doing performance stuff, not something that needs to go 100,000 miles. Class cars would be lighter.

Pinion is always checked less carrier. Then add what you need to the carrier to get total turning load number. I never do the carrier heavy enough to need a case spreader. But again, looking for performance.

40 is a bunch. Don’t think I would ever go beyond mid 20s.

Thanks! I set it at 18 last time, for just the pinion. Sounds like I'll go a touch lighter than last time and call it good. Anything in the 20 range felt pretty tight to me.

I set them up at 12-13 inch pounds, no seal, no gears. Also they like it to be vertical, I have the 1/4” beam torque wrench. 0-25 inch pounds.

13 to 17 inch lbs. on used bearings, 20 to 25 inch lbs. on new bearing with the pinion gear pointed straight up per the 1970 FSM I check them both ways, forward and reverse
Those numbers work well

Yes, same here. I set mine up at 18-20 no issues thus far several years on it street and strip.

I don't think there is enough varience in performance to worry. Make sure there is enough to keep some preload after it gets beat on. Otherwise it can beat tthe shims out. The most important thing I've learned is to loosen the backlash up to .010"-.012". If running tighter as the teeth flex they stay bent slightly and loose backlash. Then threre isn't roo for lube causing the pinion teeth to crack. Most drg race gear guys I've talked to don't like synthtic fluid either.
Doug

Thanks for all the replies!

Seems like ~15ish should work just fine.

I was thinking exactly what you said...make sure it doesn't get loose after a good beating, but not so tight it makes heat and kills the bearings. This doesn't see a ton of street cruising, but it's not out of the question that it'll see a 20 mile trip occasionally.

Hadn't thought about increasing backlash. Any theories on why you wouldn't run synthetic? It is a cushion/shock thing? I would think coming off the T-brake hits the ring and pinion pretty hard. I suppose in an 1/8mi not a lot of heat builds up in the rear, so temp isn't a concern so synthetic isn't a huge benefit.

Hadn't thought about increasing backlash. Any theories on why you wouldn't run synthetic? It is a cushion/shock thing? I would think coming off the T-brake hits the ring and pinion pretty hard. I suppose in an 1/8mi not a lot of heat builds up in the rear, so temp isn't a concern so synthetic isn't a huge benefit. [/quote]

My car leaves pretty decent off the foot brake. Mid to high 1.2X 60ft @3350-3550lbs depending on ballast. It's on it's 4th R&P. The first three all tightened up from the .007"-.008" they were set at to zero. Two of them cracked pinion teeth. One actually broke a tooth off. The cracks always start under the head of the pinion. Ring gears appear undamaged. Three different brand gear sets including one that was a pro gear. I sought out help from Moser, Strange, and a local guy Leo Zynda. All three said the same thing. Loosen it up. Don't run synthetic. First set went 425ish no cracks Motive street gear), 2nd set no brand 160ish broke pinion teeth, 3rd set 150ish (pro gear cracked teeth). The current set (Motive street gear) have 300+ with no noise. They are set at .012" wit h Lucas 85/140. Could always tell when there was a problem coming. Coast with the engine off into staging. Click, click, click.
Doug

I ran the green Redline brand synthetic gear oil in my last S/P car with a used set of stock Dana 4:56 gears and M.W. 40 spline spool and axles, lots of runs with no issues, that car weighed 2850 Lbs. with me in it and would 60 ft, in the low 1.20 off of the trans brake glide tranny
That car had a blown B1 motor and drivetrain that had 6.17 gears in that Dana 60 with the Redline Green synthetic gear oil and those gears look great when I changed them

My car leaves pretty decent off the foot brake. Mid to high 1.2X 60ft @3350-3550lbs depending on ballast. It's on it's 4th R&P. The first three all tightened up from the .007"-.008" they were set at to zero. Two of them cracked pinion teeth. One actually broke a tooth off. The cracks always start under the head of the pinion. Ring gears appear undamaged. Three different brand gear sets including one that was a pro gear. I sought out help from Moser, Strange, and a local guy Leo Zynda. All three said the same thing. Loosen it up. Don't run synthetic. First set went 425ish no cracks Motive street gear), 2nd set no brand 160ish broke pinion teeth, 3rd set 150ish (pro gear cracked teeth). The current set (Motive street gear) have 300+ with no noise. They are set at .012" wit h Lucas 85/140. Could always tell when there was a problem coming. Coast with the engine off into staging. Click, click, click.
Doug [/quote]


A long time ago (70s) Chrysler engineers found out the Dana under harsh load (clutch dropped @ rpm) the gears would actually suck (bend) into the pinion, so they recommended 12-15 thousands backlash. I think they set pattern a little different too

Yep. The Mopar Drag Seminars back in the later 70's recommended the increased backlash because the housing toes in at launch which drives the ring gear into the pinion cracking the teeth.

Good info guys! I'll loosen the backlash a tad too. Thanks for all the replies!

I think I would reset my backlash between .006 and .010, maybe as loose as .012 on used gears.
I saw a lot more than that , up too .016 possibly, I wouldn't measure the back lash on those that I was changing ratio on

I've used Amsoil Severe gear in a number of rears that have seen hard use over a significant number of runs, and the gears come out looking great.

Also been running the Amsoi[ severe 75-140 in my 1000 to 1400hp 9" stuff. Gears have been looking good so far. Jim.