AMC 401 to 700R4 to QT 2 to 4 wheel conversion

[OldFarmTruck22]

Can we do this without converting the transfer case to 2WD/4WD? I'd like to keep my 1339 factory.

[OldFarmTruck22]

So you haven't installed the adapters yet ... or you did?
You say, "They say it all fits well". I like to hear that it DID fit well before I invest the money. lol

[Jevman]

The adapter has been fit to the 700R4 by cutting the shaft on the 700R4, the QT hasn't been married to the 700R4 yet but my transmission guy say's it's all good, they will put new seals and whatever it needs in the QT while it's off but that may take a month or so.
I think you will burn up the QT if you run it without the 2 to 4 wheel conversion as i have read in other posts here which makes sense. I will update you when i can.

[tgreese]

Can we do this without converting the transfer case to 2WD/4WD? I'd like to keep my 1339 factory.

Seems this poster wants to keep the full-time capability of the Quadratrac, not run it without a front driveshaft.

As I understand it, the part-time conversion allows you to run a thinner front driveshaft, assuming the speed off-road will be fairly slow. This is also a side effect of the amount of lift you are running.

Possible you could run a pillow block and additional u-joint to move the drive shaft away from (what I presume is) the bulge in the overdrive transmission. Of course, this makes the final driveshaft shorter, which does not help the high-angle-from-lift issue.

If I were serious about this combo and keeping full-time, I would contact one of the custom driveshaft makers (ie Tom Woods) and look into something custom to replace the double cardan joint that will flex and is smaller diameter. Seems likely they have experience with interference like this.

[Jevman]

The PO of this rig was a grandma, her son was a mech in New Mex, he installed the 2 to 4 wheel conversion kit with the locking hubs and never had any problems, you just need to make sure the hubs are unlocked if you disengage the 4 wheel drive with the vacuum switch.

I haven't found anyone that has had problems with the QT yet that wasn't of there own making, just need to make sure your hubs and vacuum switch are locked in and on or off at the same time, supposedly you will wreck the QT if your hubs are locked and the vacuum switch is in 2 wheel drive.

The rest is just a clearance problem with the double CV clearing the tran pan. Your gas millage won't improve enough to care about and you may go threw tires faster in the research I have done.

As far as a pillow block, you are right and shortening the final drive will just make things harder to correct back to 0 degrees especially with a lift ( talked with Tom Woods by email, no solution at this time). If there was a 1 to 1 drop down bolt on gear box, that may work but there isn't one, not looking to tackle that big rock infested hill with this, just looking for a little more top end and the same if not better than the stock 4 wheel-drive I loved having as a kid in one of these.

[tgreese]

not looking to tackle that big rock infested hill with this, just looking for a little more top end and the same if not better than the stock 4 wheel-drive I loved having as a kid in one of these.

Not arguing with you about this - you have decided on your course. Instead, commenting to OlFarmTruck22, if she/he wants to keep full time.

Typically these Wagoneers have 3.31 axles as I recall. At 4000 RPM with 31" tires, that's a 111 mph top speed. This seems like plenty for the highway. Pretty darn sure the main determinant of fuel consumption at those speeds will be aerodynamics, not the efficiency of the transmission or final drive ratio. An overdrive transmission will reduce the engine speed some, be more efficient, and make the interior noise somewhat lower. However, this Jeep never going to be as quiet as a passenger car, considering the wind noise and tire noise and gear noise and so forth. I would spend my money on extra interior insulation, a quiet exhaust and quieter tires, if I found the cruising noise excessive. Then I'd spend the money I'd saved on more gasoline. JMO.

[OldFarmTruck22]

My question remains. I don't see where running my factory Quadratrac in factory trim will "burn up the transfer case" by me adding overdrive, and not converting the case to 2wd/4wd switchable.
If I can run at 70 mph now in the factory configuration with no problems ... how will running at 70 mph with LOWER RPMS hurt my driveline??

Sometime people overthink these things.

[OldFarmTruck22]

The adapter has been fit to the 700R4 by cutting the shaft on the 700R4, the QT hasn't been married to the 700R4 yet but my transmission guy say's it's all good, they will put new seals and whatever it needs in the QT while it's off but that may take a month or so.
I think you will burn up the QT if you run it without the 2 to 4 wheel conversion as i have read in other posts here which makes sense. I will update you when i can.

Ain't burned up yet in 44 years in fulltime 4wd high range.

[tgreese]

To OldFarmTruck, if you want to keep your transfer case full-time, you need to have both the front and rear driveshafts. If you remove the front drive shaft from a full-time case, you must lock the center differential together (in "emergency drive.") Otherwise the front output will spin, the rear output won't move, and the center differential will slip and eventually destroy itself. This is the "burning up" referred to above.

The problem with the overdrive transmission is driveshaft interference, not some issue with the transfer case. The driveshaft clears the TH400 but does not clear the 700R4, apparently. The skinny driveshaft that joeljevning is using clears the 700R4 but probably won't be ok on the highway.

[Jevman]

Thanks for explaining this tgreese, exactly! Now the reason I was asking the angle of the stock front drive is because there isn't vibration above 75mph that I ever noticed, now put a 4" lift on it and a regular 1310 (not a double CV) front driveshaft to clear the pan, it raises the angle and lowers the max RMP speed you can put on that shaft without vibration, without being home I wanted to try figure out what the top speed may be when it was in 4x4, maybe 40 mph to 50 mph? Best way to find out will be to drive it but until then just trying to guess with the charts.......This might not be practical to do if you don't have a 700R4 and a QT with the 2 to 4 wheel conversion laying around but i do, my safety light to know if the front drive shaft is turning or not when you think you have it in 2 wheel drive and it's not will probably be a high tech zip tie on the drive shaft on long trips over 50 mph.

OH, forgot to mention, you will also need to either find a junkyard Cvan that had a 700r4 and strip the shifter mechanism out of it and put it in your steering column with the indicator or replace your column, I happen to be upgrading mine to a Flaming River for the new wiring and such.

[OldFarmTruck22]

To OldFarmTruck, if you want to keep your transfer case full-time, you need to have both the front and rear driveshafts. If you remove the front drive shaft from a full-time case, you must lock the center differential together (in "emergency drive.") Otherwise the front output will spin, the rear output won't move, and the center differential will slip and eventually destroy itself. This is the "burning up" referred to above.

The problem with the overdrive transmission is driveshaft interference, not some issue with the transfer case. The driveshaft clears the TH400 but does not clear the 700R4, apparently. The skinny driveshaft that joeljevning is using clears the 700R4 but probably won't be ok on the highway.

Who said I was removing my front driveshaft? Why would I do that? I didn't ask if I could remove my front driveshaft and run a 700r4. Where did that come from?
lol
I met with my local driveline truck mechanic yesterday. They make driveshafts for custom applications. He says the 1310 will be fine up to 10,000 rpms, and the angle will not be an issue ... for my truck.