Hi gang! It's been awhile for me since I've been here. Yes, I still have my '94 Aero AWD. I've only had it 3 yrs. 243,000 miles. I bought it with 200k. Installed a used engine at 237,000. It is a workhorse. I just picked up another Aero. A '92 Awd. The front diff is trash. So, what I would like to do is drive it for awhile as a 2 wd. I removed the front cv's and installed dummy shafts. I removed the front driveshaft. When I drive it you can tell the AWD computer is occassionally trying to active the front diff (momentary slippage at initial take off.However, I am unsure if I drive it with the front sensor diff connected, will that damage anything? Or can I just disconnect the sensor for the front diff and drive this as a 2wd? I found a replacement front diff, but have no time at the moment to install it. Before I bought my first Aero, I came to this site and was completely encouraged by all the threads to purchase one. You guys definately knew what you were talking about. My first car at 17 was a 4-speed 1966 ford falcon 289. (1974) I was the only ford guy amongst Mopar racers. I took the heat and silenced the skeptics with ford performance. HeHeHe

 

If you drive it like that, I think the van might last you another week, at best.

https://www.ford-trucks.com/forums/5...d-qestion.html

https://www.ford-trucks.com/forums/5...n-trouble.html

 

What makes you think the front diff is trash. The only way to convert an AWD to a 2wd is to connect the rear driveshaft directly to the tranny and get rid of the transfer case completly. If you read a recent post on here, you will see what happens if you eliminate the front driveshaft. Very expensive to repair. Again I ask, what makes you think the front differential is trash?

 

Khan

I don't think he meant it was trash by design. It probably is broken down, and he just wanted to take it out of the loop.

 

By driving it with the front end disconnected, you're relying on the transfer case lock up clutch to send torque to the rear. The clutch is intended to lock the center diff if wheel spin occurs, then unlock.

This transfer case has a center differential that splits power between the front and rear axle, just like a rear differential splits it between the left and right wheels. And just like a rear axle with an open diff, if you unhook one drive shaft, the diff will spin up and not drive to the other output. Ford added the lock up clutch to momentarily bypass the diff to help you get unstuck or to prevent the rear wheels from spinning while driving.

In this case, the lock up clutch actuates, drives to the rear, then disengages. Then it senses the "slip" reoccuring, and locks up again for a few seconds, then disengages. And it repeates this continuously as you drive, constantly locking and unlocking the clutch. This will burn out the clutch in short order because its far beyond the duty-cycle that the clutch was designed for. So, to say that the AWD system was occasionally trying to engage the front axle due to momentary slippage is wrong. The computer is constantly cycling the lock up clutch, that's the only way the van is moving.

Along the same lines, if you unhook the t-case's front sensor, it will cause the lock up clutch to fault out completely. Without the clutch, the vehicle won't move at all. In fact, IIRC, as someone pointed out in a previous thread, without the clutch or driveshaft, the vehicle also will not be kept from rolling when in Park. So there's all sorts of reasons why what you've done is bad and should not be continued...

 

If you were experiencing a clunking noise in sharp turns, this does not necessarily indicate a bad front differential, but rather a bad speed sensor causing lockup.

 

I appreciate the responses. When I said the front diff is trash, I meant the bearing on the driver side diff is bad. The previous owner had a cv axle installed and the shop didn't torque the mounting bolts where the cv axle mates to the output shaft driver side diff. The bolts came loose and I assume put too much stress on that bearing as the cv ' flopped ' around. The good news(?) to some of you might be that I drove the aero in the ' altered 2wd mode' 25 miles. Torsen Rick, thank you very much for the detailed info. I intuitevly sensed the scenarios you that you technically explained. I had no access to the technical side of the AWD transfer case engineering scenario. Okay........Is it possible to just pickup a 2wd driveshaft after I remove the t.case? Will the shaft just ' drop ' right in? No matter which path I take......Aeros rock! Ummm.....I live in Lake Tahoe country......guess that says it all! When I'm not working, I drive the Aero......Not fishing....drive the Aero.....Not hiking.....Well....you figured it out.

 

Replaceing the bearing, or getting another front diff would not be that difficult, probably more worthwhile that disabling the AWD. Its been a while since I looked underneath one, but there is either a "spacer" that replaces the transfer case, or the RWD models have a longer driveshaft. Either way, you would need to obtain parts from a RWD to change over. Try to keep your parts things such that you can eventually switch back to an AWD.

 

I'm saving you guys a ski trip in Tahoe! Soon as I get the front diff installed. Hat off to Copper, Torsen Rick, khantyranitar. The Aero is sitting after the 25mile drive. Didnt mean to waste your time, I attempted to access related threads prior to my call for HELP! Dunno why I couldnt find those threads that Copper generously replied with. Have a great weekend!!

 

Here ya go!!

https://www.ford-trucks.com/forums/5...n-trouble.html

 

If you really want to convert it to 2wd, you need to replace the transfer case with a tail housing from the 2wd transmission, and possibly the tail shaft and companion flange. I don't remember if the rear drive shafts are the same lengths, but the one on my 4wd is steel, while the one on my 2wd is aluminum. I can measure their lengths to find out.

So, it really is easier to just replace the front axle, since you already have one of those. I assume its gear ratio is the same as your old one.

 

IIRC, the tail shafts are different between the 2WD and 4WD. To change that and the tail housing, you'd probably have to drop the trans from the van. If you wanted to go to 2WD, the simplest thing would probably be to find a 2WD Ranger or Explorer transmission of the same vintage and just swap the whole thing, one for the other. But you'd still need the 2WD Aerostar driveshaft...

When it comes to swapping out the front axle, one of these days, one of us should figure out how to put a Dana 35 SLA front axle from a '95-'01 Explorer or '98-current Ranger in place of the van's Dana 28. The SLA Dana 35 is very clearly decended from the van D28, with the same offset, narrow-axle layout.

One day when I had my Aero on the lift here at work, I wheeled a D35 axle underneath on a cart. Tape measure in hand, I found that they are indeed very similar, with the same basic mounting configuration. The D35 was a little wider, though, and IIRC, had a slightly longer pinion. So, it's not a direct fit, but still very close.

The advantages to doing this is 1) the axle is stronger (the D28 is pretty wimpy), 2) you can actually get other ratio r&p sets in addition to 3.73:1, and 3) before long, you'd be able to get an LSD for the D35 front axle. Can you imagine an Aerostar with LSD's front and rear, the center lockup clutch working right, and snow tires? It would go anywhere!

 

Eugene:

They should both be aluminum. There was a recall on the 4WD Aerostar to change the rear half of the transfer case and replace the steel driveshaft with an Aluminum one.

 

I never got any recall notice for the transfer case/drive shaft replacement. I wonder if I can still call up a local dealer about this?

 

After I bought my '95 AWD a few years ago, I called a Ford dealer and gave them the VIN. They were able to check and found that the recall had been done already on my van. You might want to do the same.