Clocking a Dana 20? - Pirate4x4.Com : 4x4 and Off-Road Forum

Flatty · 07-10-2012, 02:14 PM

I know I am going to get beat on for this, but, I ahve a TH400 at home with a fresh rebuild as well as a Dana 20. I know the 20 is considered pretty strong (besides the output shaft). I can't swing the cost of the Atlas or any other high end t-case. I DO want to clock the Dana 20 though. In all my searching, I see people have tried this by redrilling the case, and I have seen others that made a makeshirt adapter. My biggest question with the adapters, and those that made it is:

When you make the 1/2" adapter, i know oyu lose 1/2" of contact on the gears. is this an issue at all?

Any advice you guys that have built these can give me?

dima

no_bs · 07-10-2012, 03:16 PM

I assume you are talking about a Bronco Dana 20? Clocking a texas pattern seems ridiculous. I personally have broken a rear output (26 spline jeep), and cracked 3/4 of the teeth on the rear output (1/2 of those nearly broken off). This is all with a 4.7 stroker, 40" treps and T18. Beings as the 20 is a bull gear input, you cannot put a spacer in there unless I am missing something.

Mieser · 07-10-2012, 03:22 PM

It would be a little odd, but if the 6-bolt pattern on the Th400 is symmetrical you might be able to clock the factory adapter there? It would mess up the angle of the transmission mount but I think working around that would be fairly easy.

It's a 6 bolt pattern so that would be a big jump in case angle. Depending on the shape of the adapter maybe you could redrill the bolt pattern at the transmission instead of the transfer case?

77k5 · 07-10-2012, 03:39 PM

Quote:

Originally Posted by Mieser

It would be a little odd, but if the 6-bolt pattern on the Th400 is symmetrical you might be able to clock the factory adapter there? It would mess up the angle of the transmission mount but I think working around that would be fairly easy.

It's a 6 bolt pattern so that would be a big jump in case angle. Depending on the shape of the adapter maybe you could redrill the bolt pattern at the transmission instead of the transfer case?

The TH400 bolt pattern is not centered around the transmission output i.e. the bolt pattern is below center, can't clock that piece.

07-10-2012, 02:14 PM	#1 (permalink)
Flatty Registered User Join Date: Feb 2000 Member # 29 Location: Belmont, CA Posts: 6,390	Clocking a Dana 20? I know I am going to get beat on for this, but, I ahve a TH400 at home with a fresh rebuild as well as a Dana 20. I know the 20 is considered pretty strong (besides the output shaft). I can't swing the cost of the Atlas or any other high end t-case. I DO want to clock the Dana 20 though. In all my searching, I see people have tried this by redrilling the case, and I have seen others that made a makeshirt adapter. My biggest question with the adapters, and those that made it is: When you make the 1/2" adapter, i know oyu lose 1/2" of contact on the gears. is this an issue at all? Any advice you guys that have built these can give me? dima __________________ 1974 FJ40 in the works 2006 F250 crew cab longbed powerstroke for towing duties

07-10-2012, 03:16 PM	#2 (permalink)
no_bs Wheeler Join Date: May 2008 Member # 114256 Posts: 285	I assume you are talking about a Bronco Dana 20? Clocking a texas pattern seems ridiculous. I personally have broken a rear output (26 spline jeep), and cracked 3/4 of the teeth on the rear output (1/2 of those nearly broken off). This is all with a 4.7 stroker, 40" treps and T18. Beings as the 20 is a bull gear input, you cannot put a spacer in there unless I am missing something. __________________ Trail rig, '77 CJ5, 4.7 stroker, 60/14B 40" Treps/Racelines, Broken frame

07-10-2012, 03:22 PM	#3 (permalink)
Mieser Registered User Join Date: Jun 2001 Member # 5326 Location: Southwest Colorado Posts: 3,902	It would be a little odd, but if the 6-bolt pattern on the Th400 is symmetrical you might be able to clock the factory adapter there? It would mess up the angle of the transmission mount but I think working around that would be fairly easy. It's a 6 bolt pattern so that would be a big jump in case angle. Depending on the shape of the adapter maybe you could redrill the bolt pattern at the transmission instead of the transfer case? __________________ 42 MB, 225, T18, big kid go cart with clown tires 92 Dodge W250 daily driver on 39s

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