3.73 vs 4.30 LSD
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Senior User
Joined: Feb 2004
Posts: 428
Likes: 16
From: Northeast PA
3.73 vs 4.30 LSD
Hi All,
It has recently come to my attention that it may be possible to get the LSD with the 3.73 gears.
My question now is do I want it?
The LSD is a must have as the truck is 2WD.
It will be a 2WD/ F350 / DRW / Auto.
I "thought" the only way to get a LSD was with the 4.30, now I realise I might have a choice.
My trailer (currently) is about 7,000 lbs, what would you guys reccomend?
I dont want to stunt myself for future growth,,, but would probably "love" the MPG advantage of 3.73 over 4.30s if I can do it without making the truck a dog. Not sure enough about the V10s torque curve to know if it will like towing with 3.73s
Thanks for any advice (ordering on Monday...)
Cheers
jimmy p.
It has recently come to my attention that it may be possible to get the LSD with the 3.73 gears.
My question now is do I want it?
The LSD is a must have as the truck is 2WD.
It will be a 2WD/ F350 / DRW / Auto.
I "thought" the only way to get a LSD was with the 4.30, now I realise I might have a choice.
My trailer (currently) is about 7,000 lbs, what would you guys reccomend?
I dont want to stunt myself for future growth,,, but would probably "love" the MPG advantage of 3.73 over 4.30s if I can do it without making the truck a dog. Not sure enough about the V10s torque curve to know if it will like towing with 3.73s
Thanks for any advice (ordering on Monday...)
Cheers
jimmy p.
Freshman User
Joined: Jan 2003
Posts: 46
Likes: 0
From: Mission Viejo
Get the 4.30's for sure for any towing,You won't regret it.I think it is a $50 difference if not free upgrade when ordering.If you change them later,it is about $700 per axle.I have 4.30's right now with 38 inch superswampers and it drives great!But,I just bought a 34' toyhauler and loaded should be 10-11,000 lbs.I've towed it once already,and the hills killed me.Four Wheel Parts is installing 5.13 gears front and back for $1350 on Tues.That should put me in the right rpm range for the hills.
Good luck
Good luck
Senior User
Joined: Jan 2004
Posts: 169
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From: Seattle
Jimmy, the other big benefit of going to the 4.30LS, on the Dana 80 axle assy that comes with the DRW, the LS is the Detroit Truetrac LS unit which is far superior to the Ford LS that comes with the 3.73's
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Senior User
Joined: Feb 2004
Posts: 428
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From: Northeast PA
Originally posted by Chaps
Jimmy, the other big benefit of going to the 4.30LS, on the Dana 80 axle assy that comes with the DRW, the LS is the Detroit Truetrac LS unit which is far superior to the Ford LS that comes with the 3.73's
Jimmy, the other big benefit of going to the 4.30LS, on the Dana 80 axle assy that comes with the DRW, the LS is the Detroit Truetrac LS unit which is far superior to the Ford LS that comes with the 3.73's
Nice one Chaps. Thanks for that one.
See thats a "Newb" trap I could have easily fallen into.
I wonder why on the same axle (Dana 80) they choose to supply two different LS units? Detroit on the 4.30s & Ford on the 3.73s...
Is the Detroit Truetrac still friction clutch pack based,, or something newer - better???
In any case that sure makes the decision easy. As I said, with my truck only being 2WD, the quality of the LS unit becomes key.
THANKS!!!!
This forum is fantastic. Hopefully someday "I" can help others out.
Cheers
jimmy p.
Senior User
Joined: Jan 2004
Posts: 169
Likes: 0
From: Seattle
Detroit Truetrac's are only available for Dana 80's with ratios from 4.10 and up (numerically). They don't use clutch packs and don't require lube additives. It is a worm gear type differential like the old Torsen's and they work really well. I'm specing out a dually truck order right now as well and have been jumping thru all the same hoops as you so glad to share. Like you I've been a little concerned that with 4.30's the rpm's at hiway cruise speeds will be a bit high thus hurting mileage. The workaround is to swap out the 235/85's with 255/85's effectively dropping the ratio to about 4.05 which will give 65mph @1980 rpm's or thereabouts. I'm going to bring the truck in with standard street bsw tires and swap right away. I have an '86 dually that needs new tires in order to prep it for sale so its a win-win deal. Good luck!
Junior User
Joined: Jan 2003
Posts: 78
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From: Derby, Kansas
What if any would there be between a 3.73 and a 4.30 LSD?
I can't think of any difference would be needed as the difference would be the gear ration and not anything else.
If someone know for sure please advise.
Thank you,
Frankk
I can't think of any difference would be needed as the difference would be the gear ration and not anything else.
If someone know for sure please advise.
Thank you,
Frankk
Senior User
Joined: Jan 2004
Posts: 169
Likes: 0
From: Seattle
It has something to do with the ring gear thickness or mounting holes (or both, not sure) Ratios below 4.10 would require a different case so I guess they figured there wasn't enough demand to justify making it - just a guess however
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Senior User
Joined: Feb 2004
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From: Northeast PA
Originally posted by fknipfer1
What if any would there be between a 3.73 and a 4.30 LSD?
I can't think of any difference would be needed as the difference would be the gear ration and not anything else.
If someone know for sure please advise.
Thank you,
Frankk
What if any would there be between a 3.73 and a 4.30 LSD?
I can't think of any difference would be needed as the difference would be the gear ration and not anything else.
If someone know for sure please advise.
Thank you,
Frankk
Alot of times certain carriers have a "range" of dif ratios they can accomodate to keep the correct relationship between the ring & pinion.
Its very common for very low gearsets (or very high ones) to need a different carrier. Thats my guess what is going on here. The "stock" Ford in house LS carrier can only get down to 4:10 or so.
My guess is the Ture Trac is setup for 4:30 & lower (higher numerically) gear sets.
HTH
cheers
jimmy p.
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Thread Starter
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Senior User
Joined: Feb 2004
Posts: 428
Likes: 16
From: Northeast PA
Originally posted by fknipfer1
What if any would there be between a 3.73 and a 4.30 LSD?
I can't think of any difference would be needed as the difference would be the gear ration and not anything else.
If someone know for sure please advise.
Thank you,
Frankk
What if any would there be between a 3.73 and a 4.30 LSD?
I can't think of any difference would be needed as the difference would be the gear ration and not anything else.
If someone know for sure please advise.
Thank you,
Frankk
Alot of times certain carriers have a "range" of dif ratios they can accomodate to keep the correct relationship between the ring & pinion.
Its very common for very low gearsets (or very high ones) to need a different carrier. Thats my guess what is going on here. The "stock" Ford in house LS carrier can only get down to 4:10 or so.
My guess is the Ture Trac is setup for 4:30 & lower (higher numerically) gear sets.
HTH
cheers
jimmy p.
New User
Joined: Feb 2004
Posts: 7
Likes: 0
From: London
The best solution would be uprating the engine.With performance parts it would be possible to increase the torque and horsepower figures while at the same time gaining a few MPG.Besides, with more power you can pull taller gearing, hence improving fuel mileage even further.
Senior User
Joined: Jan 2004
Posts: 169
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From: Seattle
Basser, you are right - I stand corrected, the dually 3.73's are open diffs only, no LS is available. You can get something aftermarket, Dana Trac-lok I beleive, but it's not as good as the Truetrac
Tuned
Joined: Dec 2002
Posts: 365
Likes: 4
From: California
Guy's I hope I can help. I have DRW, 4.30 LS, V-10, auto. At about 70mph, empty my RPM is about 2200. I towed a 8500 # TT w/ about another 1000# in misc stuff, this past summer up the famous "grape vine" in California and she held at 55 mph and some points 60MPH. The grape vine is about 25 miles at 3.5 % grade uphill. The engine was turning about 4000 RPM. Yea, I had to put it in 2nd gear but I never overheated and checked my tranny fluid when I stopped and did not smell anything burnt. I was kind of skeptical, but overall my truck did very well. I get about 11.5 average MPG, mixed driving, empty. And sometimes I really get on it hard, just to see what's she's got. So it's not that bad for a 7000# truck with 10 burning and 4 turning (DRW's). When you have to pass on the freeway a 4.30 will do a lot better and quicker than 3.73. I would think 3.73 will do better on flat freeways, empty. But when you pass and get on her, it will take more power and torque to pass. Go for the 4.30, you won't regret it.
