Driveshaft ! Which one?

[nelzfoxes]

I did the search. I'm going v6 & c5 to v8 & tremec 5 speed. Assuming tremec is same length as t5, wagon drive shaft is too long? And mustang drive shaft is too short? Oh! Sorry, it's a 1985 ltd wagon that I'm working on. I did read about the explorer 2wd, but I'm on a budget, and just trying to throw this thing together and then build upon it.

[ZephyrEFI]

I'm using a driveshaft out of a Fairmont C4/7.5 combo in my Zeph with T-5 and 8.8. LTD is the same wheelbase, so that should work in yours too.

[Turbo-Box]

If your Tremec isn't a TKO the stock driveshaft should swap right in. A TKO uses a C-6 yoke.

[roadkill]

What ZephyrEFI said. V8/C4 shaft fits perfectly.

[nelzfoxes]

Thanks all! Looks like I'll be spending some time at the yard. I know it's in another thread somewhere, but what is the length I'm looking for? Exact number.

[nelzfoxes]

I measured an explorer driveshaft at work last night and it was 51" c-c. Today I measured the wagon driveshaft at 51 1/2" c-c. Now I'm thinking the wagon driveshaft will work unless there's a big difference in yokes which changes length from flange to flange. I'll measure from flange to flange tonight and report back.

[JACook]

Forgive me if I'm reading this wrong, but there seems to be some concern that this being a wagon makes
a difference. It doesn't. There's no difference between the driveshafts for sedan or wagon. All versions of
Fairmont/Futura/Zephyr/Z7 and Fox LTD have the same wheelbase.

Fairmont 302/C4 shaft is 51.25" C-C.

[nelzfoxes]

I know there's no difference, I just reference it because it is what I'm working on. Sorry about the confusion. I put up the wagon driveshaft just for ****s and giggles and the flange is about 3/8" away from the transmission. I can see the trans seal through the gap. That extra 1/4" is needed I guess? I'll try to take pics.

[JACook]

OK, first, you need to measure the slip yoke clearance with the weight of the car on the rear suspension.

You need enough clearance so that as the rear suspension compresses, the driveshaft is able to get "shorter"
by sliding the yoke further into the transmission. The overall operating range is usually in the neighborhood
of ~3/4".

If you have ~3/8" gap with the car on it's rear suspension, and your rear seal is the type with the extra ~1"
dust boot over the actual seal area, you should be in good shape. If your rear seal is basically flat and you've
only got 3/8", I would compress the rear suspension against the stops and check again.

You do not want the yoke to ever bottom out against the seal, and you especially don't want it to bottom out
against the end of the mainshaft either.

[nelzfoxes]

I took pics, just haven't had a chance to put them up yet. The rear is sitting a little low because of the mustang springs and the gap is 3/8 between flange of yoke and transmission tail. The seal extends beyond trans about 1/4 inch and is visible in the gap. If everything were solid bushings and torque boxes and frames didn't flex, then I might get away with it. But it looks like I'm gonna have to find a driveshaft or get this one cut down.

[mustangjoe413]

If I remember correctly I used a driveshaft out of an 85 Cougar 302/AOD in my 83 LTD Wagon with a 302/408 and a C4. Just another option for you.

[BRWSaver]

Not sure if they changed the diameter of the driveshaft from 1979 to the end of production, but when I swapped the SROD for the C4 and had to get mine shortened the drive shaft shop recommended going to a larger diameter. Seems the stock 1979 Fairmont shaft was kind of marginal at its length and diameter for speeds above regular freeway driving.

Just something to consider if you do need a different shaft. (luckily for me the guy just found another Ford shaft that was bigger from his huge pile of cores and made it the right length for me, didn't charge me any more to do it)

[nelzfoxes]

This is a 2wd ford explorer. Disregard what it looks like and the fact that it is right hand drive.

[nelzfoxes]

This is how long the driveshaft is.

[nelzfoxes]

Btw, Here is the gap I was referring to.

[nelzfoxes]

I'm looking at purchasing another rear right now, but I m still gonna need a new driveshaft. I think I'm going to go with the explorer 2wd driveshaft. Just gotta track one down.

[slpr50ltd]

Yeah, the yoke is way too close in the photo you provided. On my '85 LTD Squire conversion with a '90 Mustang 5.0 and FRPP "Z" T-5, I used an '85 Thunderbird Turbo Coupe automatic shaft. It fit nearly perfectly. I have one of the seals with the boot on it and have about 1/4" between yoke and boot. The car has been together for four years and has had approximately 20K added to the odometer with no issues.

[nelzfoxes]

Well, I haven't gotten a new driveshaft yet, but I picked up a new rear suspension setup. That's right! I got an 04 IRS! I am pretty excited. Now my problem is I work 56 hours a week which leaves me little time to wrench. Aargh!

[roadkill]

An LTD wagon with IRS? Sweet!

[nelzfoxes]

An LTD wagon with IRS? Sweet!

Thanks! But we all know I'm not the first! Mine won't have a big block any time soon though.

[ZephyrEFI]

Awesome! Can't wait to see this progress!

[roadkill]

Curious to know how I can source one of those postal Explorer shafts. I work in Ford parts and can order a new one but YIKES is it a lot of $$$, almost a grand! I have to see a wrecked postal Explorer in any yard.

[nelzfoxes]

The post office would probably have to pay quite a bit more than you. Just have to go to junk yards I guess. That's what I'm going to have to do. I don't think it's anything specific to a postal vehicle. Just what the exploder came with.

[nelzfoxes]

Okay. I drove 3 hours each way this morning for a driveshaft out of a 2000 Eddie Bauer Edition Ford Explorer 2wd! The driveshaft bolts right up to the Cobra IRS flange and measures 50 3/4 inches long. Whereas the wagon driveshaft I posted earlier was like 51 1/2 inches long. Now I just need a trans yoke with the correct spline pattern for the t5/tremec which takes the larger u-joint of an aluminum driveshaft. I woould post pics of IRS and driveshaft, but I keep getting a message about file quota when I try to upload. Yes, the driveshaft is exactly the same as the postal driveshaft posted earlier! Found it on ebay for $65, pick up only. Long drive, but worth it to me anyways!

[roadkill]

Would that driveshaft fit a conventional 8.8/C4 combo ok, even tho it's 3/4 in shorter? Pull-A-Part near me has a whole bunch of Explorers and I would love to be able to use one of those aluminum driveshafts.