infamous squeek/thud on takeoff

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Apr 25, 2001 | 04:54 PM

rockcrawl

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infamous squeek/thud on takeoff

My '92 F150 351 E4OD 4X4 w/60k miles has the infamous squeek/thud every time I accelerate from a stop. Searching the forum has confirmed my suspicions of a binding slip yoke on the rear drive shaft. I also get slight vibration at high speeds. A 6" lift and short wheelbase is not helping the situation at all. Is there any way the convert the T-case to a stationary yoke and a custom shaft with a slipper? Any info or part #s pertaining to the TSB on this? I guess I will just grease it for now.

Apr 25, 2001 | 07:21 PM

mjb1962

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infamous squeek/thud on takeoff

Do you presently have a Borg Warner 1356 transfer case with a slip yoke output? If so you can convert to a Borg Warner 1756 transfer case. The 1756 is a 1356 that has a fixed output yoke that will bolt up to a double cardan CV joint. The 1756 was used in Bronco's and some short wheelbase vehicles. The CV will more than likely correct your vibration if it is caused by excessive or mismatched u-joint angles. If you convert you can have a driveshaft manufactured. You must also set the rear u-joint angle to near zero degrees, I believe 0.5 degrees is ideal. I did this on my lifted 89 F150. Any questions email me at mjb1962(No Email Addresses In Posts!)
Mark

Apr 25, 2001 | 08:57 PM

jakegypsum

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infamous squeek/thud on takeoff

I would also check your tranny mount. I had a similar noise like this about two months ago. My problem was the bolts going to the trans from the tranny mount. Good luck.

Jakegypsum // Ford fleet, soup to nuts.

Apr 25, 2001 | 09:40 PM

rockcrawl

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infamous squeek/thud on takeoff

I'm not sure what t-case I have, I was hoping someone here could tell me. I'll see if I can find some ID on it. It does have the slip yoke output shaft. The splines are somewhat over-extended from the 6" lift and they are loose, the shaft wobbles a bit. I believe the splines are binding under torque when the axle housing twists upward. I've read that ford put out an updated part with better support bushings or something, but I'd rather convert to a fixed yoke and possibly a CV jointed shaft. If it is a Borg Warner 1356 transfer case can I use parts from a 1756 to convert it or will I need to swap the whole unit? Any idea what year trucks used the 1756?

Apr 26, 2001 | 05:02 PM

mjb1962

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infamous squeek/thud on takeoff

The 1756 is a 1356 with a fixed rear output yoke that will accept a CV. I believe late 80's into the 90's on F series and Broncos for these cases. My 89 F150 had a 1356. I replaced it with a 1756 and had a custom driveshaft made. Solved alot of problems such as vibrations. There should be a metal tag on one of the tail housing bolts. Look on the top left part of the tag near the mounting hole and you should see a number with 1356 followed by a few groups of numbers. I bought my 1756 from 4xheaven (www.4xheaven.com) in NY state. Had the driveshaft manufactured in CT, however, Tom Woods (www.4xshaft.com)in Utah is also excellent. I do not believe it would be practical to try to convert it to a 1756.
Mark

Apr 26, 2001 | 06:24 PM

cgl

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infamous squeek/thud on takeoff

Converting would be more hassle than it's worth. The slip yoke splines are part of the drive shaft that comes from the tranny. You'd have to replace this (which would require complete disassembly of the x-fer case) as well as the tailhousing. And then hope the inner gears aren't different. I've never done this, so I can't say for sure.

Apr 26, 2001 | 07:08 PM

mjb1962

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From: Connecticut

infamous squeek/thud on takeoff

Rockcrawl,
Swapping the case is easy except for the two top bolts. Don't even consider modifying yours. You could probably sell it in the classified ads. I swapped mine by myself in the driveway without using any transmission jacks. It is not a very heavy unit. If you swap, you will gain a bit of ground clearance at the rear of the driveshaft since you must rotate the axle pinion up to obtain the near zero degrees on the rear u-joint.
Mark