infamous low speed clunk

[fireguy12117]

my 93 has always had the infamous low speed clunk where coming to a stop you feel something thunking in the drive line and then again when taking off. if i stomp on the gas i dont feel it. i also *thought* it got worse as i drove along and things got up to running temp (read transmission).

its got a 1 pc drive shaft swapped in there, but last i knew everything was in phase, aligned well and greased like a...well anyway, where i do start looking?

oh yeah, 3.73 open rear end for now. got a doner axle and 4.10LS to go in this fall perhaps.

 

[Wicked_Sludge]

i wasnt aware of any "infamous clunks".

my first thought would be u-joint(s). if it was the differential itself, it probably wouldnt have lasted as long as it has. if its not u-joints, more diagnostics are necessary. is this a manual or automatic? 4x4 or 4x2?

 

[martin]

radius arm bushings

 

[fireguy12117]

wicked- 93, 4x4, A4LD auto.

i had said infamous as a bit of a joke, remembing that service bullitens went out about the drive shaft spline grease drying up on certain years, but i had also remember some pople posted similiar symptoms with different causes.

such as rad. arm bushings!

how does one check those out? does the weight need to be off the tires and you wiggle things around? can you apply pressure somehow in the directions the truck experiences when accelrating a decel.?

 

[Sasquatch_Ryda]

There is actually a TSB for this exact problem for 98 and up ranger with the 1 peice steel drive shaft (which you are using) for a driveline clunk when comming to a stop and starting off. It is the slip yolk on the drive shaft that is the casue and ford came out with a special grease to solve this problem. After that ford when to a 1 peice drive shaft made of aluminum.

 

[Wicked_Sludge]

the best way to check the condition of the bushings is just to pull the nut, washer, and the rearward bushing out and visually inspect the forward bushing.

heres my old passenger side bushing (right) next to the new bushing (left). note the gash in the inner (the taller) bushing that was allowing metal to metal contact of the radius arm and the bracket.

 

[rickcdewitt]

clunker

my truck clunked when you hit the gas or let off it fast before i rebuilt the rear end you might try setting the e-brake putting the truck in neutral and crawling under the truck and rotating the driveshaft while looking at the rear end it shouldent move back and forth a lot.ive seen worn out rears move almost a half turn and clunked like you said. my truck is a manual tranny so it was easy to load/unload the drivetrain and make it clunk.

 

[Ozwynn]

I'll vote radius arms, every TIB and TTB Ford I have ever had has done that and it has always been the radius arm bushings........ let 1 go on a 2wd F100 too long and cracked the lip around the eye on the bracket.

 

[Ozwynn]

Let me Clarify that. I would start by looking at the radius arm bushings. It could be alot of things, but in a 93 TTB rig the radius arm bushings are the most likey.

 

[fireguy12117]

well, lubing the drive shaft slipe yolk a second time seems to have helped a lot. i had lubed it when i first threw it in, but this time i just slathered the stuff in there. is that what has to be done? i couldnt feel any binding with the shaft out, so are there other forces in other directions when its in the truck that will make it bind? i'm not totally convinced that this was all of the problem, so i will be evaluating the radius arm bushings when i get the chance.

 

[Cooper443irty]

Does anyone have the Ford part number for this specail grease. I have a 98 ranger with the same problem.

 

[Sasquatch_Ryda]

Does anyone have the Ford part number for this specail grease. I have a 98 ranger with the same problem.

Go into your Ford dealer and ask for PTFE lubricant and they should know what you are talking about. If not their service department will be able to look up the TSB and it will have the part number.

 

[skippy]

I'll vote radius arms, every TIB and TTB Ford I have ever had has done that and it has always been the radius arm bushings........ let 1 go on a 2wd F100 too long and cracked the lip around the eye on the bracket.

i had a ugly twotone green fullsize truck did same thing.i vote radius arm bushing too.4604brl,ugly as hell,but it was fast!

 

[DBCcatcher007]

I had the same problem and it progressively got worse. It turned out to be the U-Joints