63 Panel rear differential

[nadodave]

So I finally drove my 63 Panel the other day - pretty sure it has been off the road for more than 15 year - 13 I know for sure because that is how long I have owned it . It now has a warmed up SBC/700R4 combo, and a 71 disk brake front end. The good news is that it drove surprisingly well. The bad news is that either my 700R4 was not shifting into OD, or I have a felony (numerically) high rear end. The panel was originally a 6 cyl 3 speed combo.
My goal is to have a highway cruiser than can also tow a car trailer, and I am OK with drum brakes in the back. I read in this forum that later rear ends are wider and presumably problematic to install. Questions: 1) Any idea what the stock rear axle ratio is? 2) Can just the gear set be replaced in my differential, and if so, what should I look for, 3) Other ideas?

Also, good ideas on how to troubleshoot the OD issue - other than going to AMMCO?


Thanks

[Southcity]

Have you double checked your 700R4 TV cable to ensure it is installed correctly (no obstructions) and also properly adjusted? This can affect shift performance and there is a lot of information about it here in the board. Hopefully others will chime in regarding your rear differential questions.

[nadodave]

I have looked at the TV cable briefly, and was sort of surprised that it seemed loose. That said, the 1-2 shift seems to happen at about the right speed. Will research more.

[cwcarpenter98]

So on the rear axle, you probably have either a 3.73 or a 4.10 gear if it's a half ton. Should have a 12 bolt rear with the trailing arm mount welded to the passenger side axle tube. If that describes your rear axle, changing gears could be done, but you have 17 spline axles. Makes it a lot harder (more expensive) to swap to 5 lug (if that's your plan) while keeping that axle. You could switch to a 65-70 axle to get 6 lug, 31 spline (I think that's the number) axles which are stronger, or you could get a 71-72 5 lug trailing arm rear that is a tad bit wider but will still have the coil spring mounts. There's also the option of a totally different axle that would need welding to make fit

[Captainfab]

Your TV cable absolutely must be adjusted correctly to achieve the correct line pressures. And the cable must be attached to the throttle arm with the correct bracket and correct geometry. If you drive it without this done, you will burn up that trans in a short time. There is a ton of info here on the forum in the Engine and Drivetrain section all about how to accomplish this. Your differential more than likely has 3.73 gears which are just right for use with an OD trans.

[nadodave]

So, took the panel to a highly rated trans shop, and they determined it was toast. No more than 30 miles on it. Evidently, the first rebuilder put a lock up torque converter on it and failed to do some other required tweaks. $1800 later I have a rebuilt (again) trans - this time with a warranty!
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[nadodave]

On the rear axle: I presently have 6 lug axles and prefer to Keep them. I think my diff is a 12 bolt - will confirm. Can I just change the ring and pinion?
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[Captainfab]

Yes you can change the ring and pinion gears. Why do you feel you need to change gears?

[nadodave]

Originally Posted by Captainfab

Yes you can change the ring and pinion gears. Why do you feel you need to change gears?

Hoping for lower RPM on the highway.
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[Captainfab]

Your 700R4 will take care of that. You do not want to go with too high of a gear with an OD trans. The lower the rpm does not necessarily mean better mpg's. The engine needs to operate in it's power band.

Originally Posted by nadodave

Hoping for lower RPM on the highway.
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