Clunk or slam?

[jdk]

when i put my '93 F-150 into gear it cluks or slams. its more of a sound that anything. does anyone elses truck do that?

 

[LEB Ben]

Have you checked your driveshaft for any play at the u-joint? Put it on jack stands, put it in neutral, then shake the hell outta that bad boy and see if there's any play.

Do you have a transfer case, could be coming from there too.


I suppose the transmission could be an issue as well, but I couldn't help there.

 

[1985 Ford F-150]

Id say the most likely is the U joints but it could also be the rear end has some slop in it.

 

[blacksnapon]

Make sure your idle isn't too high as well.

 

[Alvin in AZ]

Id say the most likely is the U joints but it could also be
the rear end has some slop in it.

x2! ...and especially on the axle idea, if it's an 8.8".

U-joints and axles are easy to get under there and feel for slop.
I have 4 in my yard (my neighbors love me and the 8.8s twist
a good 3/4" at the hub and the 9" and 10.25" twist a little less
than half as much.

Hoping a new Eaton True-Trac will tighten and toughen one of
them 8.8's up ...but will it? (hadn't torn apart an 8.8" yet)

Alvin in AZ

 

[Alvin in AZ]

I suppose the transmission could be an issue as well,
but I couldn't help there.

I inherited a '91 F150 XLT 351w E4OD with 66k on on it.
It clunked to beat hell when switching from drive to reverse.
It was so loud, people standing around "seeing me off" would
comment on it!

Talked to my neighbor about it and he told me it was the axle
if it's an 8.8 especially and for sure not the E4OD. He's a Ford
guy that owned his own automatic transmission shop that his
son now runs.

I found a loose u-joint on my '91 Bronco last week and it didn't
clunk, it vibrated. IME u-joints vibrate way before they clunk.

It had a little less than 1/8" end play so the whole shaft could
get out of alignment by maybe 1/16"(?) and that's a lot on a
driveshaft. Got the wheels up off the ground and wedged open
the throttle body and I could see that the driveshaft wasn't
spinning true. When a driveshaft isn't crooked and it's balanced
good, it spins smooth and true as anything you ever saw. LOL

Ok, that measly 1/16" out of alignment equals ~1/8" (counting
both ways) then you add the flex from the centrifugal force,
so out in the middle, it was like 5/16" "out of whack".

Alvin in AZ

 

[LEB Ben]

^^^I hear ya Alvin...that's why tranny was my last suggestion. U-joint got my top vote as well, followed by transfer case if he has one. I was just throwing potential options out there.

 

[Alvin in AZ]

U-joint got my top vote...

I'm voting for the 8.8" ...but really now... it's easy as anything for 'im to get
under there and figure it out (maybe with some help) and get back here and
-tell us-. LOL

Butthead in AZ

 

[jdk]

Update:
my truck is 2wd, E4OD and and 8.8 witch seems bad after reading. i had an 88 F-150 with an AOD and 8.8 limited slip, same ratio as the '93 and it never clunked at all. The U-joints are tight i check those. I always let the truck "warm up" for about 5 minutes or so because it idles very high for the first 30seconds or 1 minute, give or take. the sad part is, i gave away the 8.8 out of the '88 about a year before i got the '93. DAMN-IT

 

[5.0Flareside]

take it to a trans shop and them check it out... any trans shop also should do rear ends.... and if they are any good, they'll be able to pinpoint the issue almost imediatly...