Quadratrac to Dana 20 swap

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gladiator
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Quadratrac to Dana 20 swap

Post by gladiator »

Looking for some history on this combination and thoughts on what is needed to do this swap.

Am starting with a 74 J10 with original T400/Quadratrac drivetrain, the plan is to swap in a Dana 20 behind the T400. Already understand there are output shaft/drive gear and other differences between QT and D20.
So, have found a complete T400 trans & D20 transfer case from a mid 60s wagoneer. Apparently this was originally mated to a different engine (Buick or Rambler maybe) than an AMC .
This donor T400 case has the round belhousing pattern similar to the AMC 360 pattern, and when arrived it came with a thick cast iron housing adapter. The odd thing about this T400 trans case is a starter clearance bump on the driver side.

So the Question for the history experts, did the Buick have driver side starter motor position unlike the Pass side starter on the AMC?
Am starting to think this trans is really only good as a donor of the transfer case adapter, trans output shaft and drive gear for the D20? Would you agree or ?
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460

440sixpack
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Re: Quadratrac to Dana 20 swap

Post by 440sixpack »

The output shaft should fit any TH400. I think my adapter is aluminum but as long as yours fits that doesn't matter.

AMC TH400's in the quatra trac era had a cant to the left that you can't miss. whether you need this for the Dana conversion I can't say, but when I did mine I have the canted case.

Mine is done and it works fine. if I had it to do over I would have just put the part time conversion in my QT and called it good. it's not worth the hassle in my opinion.

Topic author
gladiator
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Re: Quadratrac to Dana 20 swap

Post by gladiator »

Thanks, had put a mile marker PT setup in this previously. Personally, Not really happy with it.

Lots of cold weather use here and the little diaphragm fork mover is weakish on shifts when cold when really need a quick shift. And this swap will deal with the chain stretch for good.
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460

Topic author
gladiator
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Re: Quadratrac to Dana 20 swap

Post by gladiator »

https://photos.app.goo.gl/nJT5IfOyPDHH8C4g2

Hope this link works. This is the T400 case

And this is the flex plate that came with the trans.
https://photos.app.goo.gl/XXlL8kLnV1UC5w3m2

https://photos.app.goo.gl/CmN1SZEKq5XFF2Bo1
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460
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Tatsadasayago
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Re: Quadratrac to Dana 20 swap

Post by Tatsadasayago »

The D20 is a superb transfer case but it's not bullet-proof. Probably it's greatest weaknesses are leaks and it's straight-cut gears. Maintenance is the key to long life.
1977 Cherokee Chief - The Blair Jeep Project III
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fulsizjeep
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Re: Quadratrac to Dana 20 swap

Post by fulsizjeep »

gladiator wrote:Thanks, had put a mile marker PT setup in this previously. Personally, Not really happy with it.

Lots of cold weather use here and the little diaphragm fork mover is weakish on shifts when cold when really need a quick shift. And this swap will deal with the chain stretch for good.
I am not really a fan of the PT kit. The contact surface of the 4wd coupler is very small and lends to slipping, especially if the vacuum shifter is sketchy. On the vacuum supply for shifting, if you are not using the metal vacuum lines provided by the factory then you are probably running several feet of rubber lines which tend to collapse under vacuum.
Flint Boardman
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s
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tgreese
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Re: Quadratrac to Dana 20 swap

Post by tgreese »

What's the situation for the nailhead transmissions today? I thought the convertors and flexplates were NLA, and it's better to step up to the later 1-piece AMC TH400 case. If you swap to a Dana 20, and take the transmission apart to do it, that might be a worthwhile addition.

If you want to keep your D20 from leaking, I suggest you read some threads on fixing leaks in the Dana 18 on earlycj5.com. The two cases have mostly the same issues regarding leaks (the Dana 18 is worse) and the CJ guys have put a lot of thought and effort into plugging the usual sources of drips.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
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HeavyMetalThunder_81
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Re: Quadratrac to Dana 20 swap

Post by HeavyMetalThunder_81 »

You will need to swap the transmission output shaft and adapter/bull gear assembly out of the nailhead TH400 and into your AMC TH400. I hope you got the transmission/transfer case to cross member mounts from the donor vehicle as they are different than the Quadratrac ones. Honestly, if I had the chance to do it again...I wouldn't.
-Jonny B.
1979 Cherokee Golden Eagle - UNDER CONSTRUCTION
7" lift, 35x12.5x15
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tgreese
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Re: Quadratrac to Dana 20 swap

Post by tgreese »

So is this AMC transmission currently used with the OP's Quadratrac a nailhead case or an AMC case? Does it have an adapter ring (nailhead type) or not (AMC type)? IIRC could be either for a 1974 Jeep.

The "Rambler" 232 that was offered 1965 to 1970 has the starter on the driver's side. Not sure about the 327 position, or the 350. It won't make any difference, since all you want is the output shaft.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

Topic author
gladiator
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Re: Quadratrac to Dana 20 swap

Post by gladiator »

Thanks folks, all good info.
1. on the vacuum lines: yes this truck was all rubber hose from firewall to the Vac actuator. I know the diaphragm in the actuator is good cause I tested. You raise a good point, there are probably a bunch of minor leaks adding up to a major one. And as I think about it, the need for "4WD engage, NOW" is at WOT, which is minimum vacuum. So the procedure should be to engage 4WD at closed throttle before it is needed.
2. thanks for the reminder on sealing up this case. I have had a couple of these D20s and some days I think the iron itself is porous. Just sweats the oil out.
3. The trans/transfer case came as loose package, no crossmember, someone else had pulled it long ago. I guess bust out the welder.
4. Appears this older T400 will be donating the output shaft/gear and housing adapter to the project.

Here is another question.
the D20 here has the old J type lever shifter. this one is quite worn at the shifter housing bushings and I would like to keep it rather than twin stick this truck. Does anyone know where to get the bushings etc to repair the shifter?
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460

Topic author
gladiator
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Re: Quadratrac to Dana 20 swap

Post by gladiator »

Here is image of the cast iron adapter fitted to the front of the trans case. I realized last eve that this supports the pass side starter position.
https://photos.app.goo.gl/fgqXSIt09quFeVK02
https://photos.app.goo.gl/n8UOm9GuR47ChAfj2


Here is link to image of the shift lever housing with the worn bushings. Most of the folks on here probly already know what this looks like.

https://photos.app.goo.gl/RSoU4OSkW9BV0dCE3
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460
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tgreese
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Re: Quadratrac to Dana 20 swap

Post by tgreese »

You understand the cast iron adapter is how all the Jeep engines were adapted to the TH400 prior to 1974-ish? The Jeep application uses the so-called "universal" or "nailhead" transmission, selected for adapting to non-GM engines specifically because the nailhead Buick V8s (from the 50s) needed the shorter case. Using the shorter nailhead case provides room for the adapter. There was a unique iron ring for the AMC 327, the Rambler 232, the Buick 225 and 350 (only for Jeep applications), and the AMC 258/304/360. The iron adapter rings also require a unique bushing between the crank end and the convertor. IIRC Jaguars and Rolls Royce (?) used the nailhead TH400 for a while too.

Around 1974, Jeep changed to a one-piece case that bolts directly to the AMC engines with the unified pattern, ie the later 232, the 258, 304, 360 and 401.

Shifter pic does not work - comes up blank. I know that I took my J10's shifter apart and cleaned it of hardened grease, lubed it well, and although worn, it was much improved.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

Topic author
gladiator
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Joined: Fri Jan 30, 2015 6:19 pm

Re: Quadratrac to Dana 20 swap

Post by gladiator »

Ah, this is the info I was looking for. As mentioned in original post, the starter position on that shorter aluminum case was on driver side. I had not seen such a short T400 case before and didn't realize that the T400 case was built in different length specifically for the buick.
I think I am missing the spacer bushing and the flex plate/ring gear is trashed. It seems to me that stripping this older trans for the output shaft and drive gear is best. It forces the checks of the clutch packs at the same time.

Are any of the links to photos working or is this google photo hosting just not worth the time? (what works best for this forum?)
To explain, the rods In the shift lever housing that extend back to the transfer case ride appear to ride in brass bushings. the bushings at the shift lever housing are totally worn out and movement of the shift lever causes inconsistent movement at the transfer case. EG; it does not reliably do the 2H to 4H shift unless you get really rammy with the shift lever.
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460
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tgreese
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Re: Quadratrac to Dana 20 swap

Post by tgreese »

I'm home now, and the shifter pic is ok. My work arbitrarily blocks some things... I can't make sense of their criteria.

My '77 is newer and comparatively low miles, so less worn. Maybe you could look for used parts that are less worn out.

The Buick nailhead blocks stick out to meet the transmission case, thus the transmission case is shorter. You can see that here - https://www.nailheadsforsale.com/sold.html
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

Topic author
gladiator
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Joined: Fri Jan 30, 2015 6:19 pm

Re: Quadratrac to Dana 20 swap

Post by gladiator »

Thanks for the link to the Buick engine pages.
Not many of these still around here. Most of these old trucks went to the crusher.
64 J300. SB Chevvy, T98, D20.
Donor waiting in the wings; 92 F350 with 460
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