Dana 70 going bad.
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Modular motor junkie
Joined: May 2009
Posts: 6,190
Likes: 8
From: Texas
Dana 70 going bad.
I have a 99 E350 superduty SRW with a D70 3.73.
It has a lot of slop, to the point you can move the drive shaft 1/8 of a turn back and forth. I had never felt this tell 2 weeks ago. I have a 4.10 D70 from a 83 DRW. I think that towing 16-18K with a highway ratio is what hurt it. can i do this swap, and how do I fix the speedometer and odometer?
I will be getting a 5 star tune to fix the shift points.
BTW, the 99 is a van and the 83 is a pick-up.
Thanks for the help guys.
It has a lot of slop, to the point you can move the drive shaft 1/8 of a turn back and forth. I had never felt this tell 2 weeks ago. I have a 4.10 D70 from a 83 DRW. I think that towing 16-18K with a highway ratio is what hurt it. can i do this swap, and how do I fix the speedometer and odometer?
I will be getting a 5 star tune to fix the shift points.
BTW, the 99 is a van and the 83 is a pick-up.
Thanks for the help guys.
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
The tuner should recalibrate the speedo. Just double check that your VSS is trans mounted and not on the pumpkin. If yours is on the pumpkin, then the 83 will take some work get the speedo hooked up.
If the ring and pinion were setup correctly, holding a constant speed is easier on the parts than the acceleration and gear changes. Nothing last forever though, after 10 year and probably 120k, the axle was most likely in need of some attention.
If the ring and pinion were setup correctly, holding a constant speed is easier on the parts than the acceleration and gear changes. Nothing last forever though, after 10 year and probably 120k, the axle was most likely in need of some attention.
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Modular motor junkie
Joined: May 2009
Posts: 6,190
Likes: 8
From: Texas
It is at 160K and most of it heavy towing in the city, not highway. Lots of starts,stops shifting etc.I am thinking of swamping the gears from one axle to the other rather than a whole axle swap. What about the odometer? Is it run like the speedometer or is it a cable?
How muck strain will the 4.10s take off the rest of the drive train?
Both the trucks are non LS. Is there a way to make it limited slip when i am in there or would i need a whole LS diff. assembly to do that?
How muck strain will the 4.10s take off the rest of the drive train?
Both the trucks are non LS. Is there a way to make it limited slip when i am in there or would i need a whole LS diff. assembly to do that?
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
All speed and mileage is from the VSS (vehicle speed sensor). When you correct the speedo, the odo will follow in line.
I don't think it's so much strain as in applying more torque with less effort. If you're dumping 160ft-lbs out of the engine, then the trans will amplify it and the higher value will travel down the DS to the axle where it gets amplified again. Once the torque reaches the tires though, the power is reduced by the diameter of the tires. It works around to the final drive ratio. A low gear just requires less power from the engine to do the same work, but at a cost of rpms.
If you have an open diff, you will have to change the carrier to get LS. There was a factory LS option and the clutches/design was rather poor. They wore out faster than most tires, but they are rebuildable.
I don't think it's so much strain as in applying more torque with less effort. If you're dumping 160ft-lbs out of the engine, then the trans will amplify it and the higher value will travel down the DS to the axle where it gets amplified again. Once the torque reaches the tires though, the power is reduced by the diameter of the tires. It works around to the final drive ratio. A low gear just requires less power from the engine to do the same work, but at a cost of rpms.
If you have an open diff, you will have to change the carrier to get LS. There was a factory LS option and the clutches/design was rather poor. They wore out faster than most tires, but they are rebuildable.
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Modular motor junkie
Joined: May 2009
Posts: 6,190
Likes: 8
From: Texas
If the factory LS was poor what is there for after market that is affordable?
I saw on your " too many mods to list, so click here" that you went from 3.73 to 4.56.
What motor do you have and how do you like the change in gearing?
how well does it help towing and how bad did it hurt mpg's
I saw on your " too many mods to list, so click here" that you went from 3.73 to 4.56.
What motor do you have and how do you like the change in gearing?
how well does it help towing and how bad did it hurt mpg's
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
There are options for diffs. Ranging from the $200 lock rights up to $4-600 lockers. For streetability limited slip types are pretty nice, Eaton traction makes some great units sold under the Eaton and Detroit labels. Auburn isn't too bad, but probably not great for these heavy applications. Then you get into selectables like ARB and Eaton E-Lockers.
I'm very glad I changed, but I wish I had gone 4.88 while I had it a part. I have a 5.4L. It did help quite abit in take offs and pulling up sand hills. I lost ~0.5mpg in the 3.73 to 4.56 with 35" tires for both base lines.
I'm very glad I changed, but I wish I had gone 4.88 while I had it a part. I have a 5.4L. It did help quite abit in take offs and pulling up sand hills. I lost ~0.5mpg in the 3.73 to 4.56 with 35" tires for both base lines.
Thread Starter
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Modular motor junkie
Joined: May 2009
Posts: 6,190
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From: Texas
I want the best gear for a balance of pulling power and mpg. I think I will just go ahead and put the 4.10s I have in, but i am not sure. I want 4.88s, but do not want to run 2850 RPM in OD going 70. I do not live in heavy hills, and the V10 with 3.73,s is not that bad at highway speed. The problem is from a stop. I do not like the fact that the 4R100 has no granny gear and have I am thinking of a 6 speed swap in the future.
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Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
Gear ratio should be a balance of your tire size to cruise speed/rpm. If your cruising at 70, I would pick the ratio that put me at 2000rpm with my tires. Really I think this would be closer to 4.30s with stock tires and 4.88 with 35" tires. But I didn't run them through a calculator.
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Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
I think you'll be pretty happy with it. I'm pulling a theoretical 60mph at 2000rpms, reality is about 68mph because of roll on my tires. So your going to be pretty close in RPMs to me, but an extra 30-40hp.
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Modular motor junkie
Joined: May 2009
Posts: 6,190
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From: Texas
I just do not like starting from a stop.
The first gear is so high ( low number ) that it will not pull off the line.
I will have to put up with it tell I can put a 6 speed in,
The first gear on it is double what the first is on the 4R100.
The first gear is so high ( low number ) that it will not pull off the line.
I will have to put up with it tell I can put a 6 speed in,
The first gear on it is double what the first is on the 4R100.