92 f250 4x4 460/E4OD SuperCab L/B. I have an issue that I can't figure out or seem to get an answer to. This truck has a 2-piece driveshaft with a center support (carrier) bearing, which is mounted to a factory drop bracket that's attached to crossmember. Original driveline (newly rebuilt) carrier drop bracket was 6" drop, causing 1st section of driveshaft from t-case to bearing to angle downwards to bearing. Rear section was almost straight (no angle) from bearing to rear pinion. I had a shudder under low-speed accleleration when pulling trailer, was told these angles were wrong (although factory??). Rear springs/axle fine, not sagging - checked by spring shop.
I got a 4" carrier drop bracket from a salvage, cut rivets on the original 6" and installed 4". Driveline angle is now nearly symmetrical angled slightly downward frt to rear along entire length. However, carrier bearing is mounted vertical, driveshaft runs thru it at a slight angle and new bearing is now howling after less than 1000 miles??. I have looked under so many Ford trucks at wrecking yards my head is spinning. There are apparently at least 4 different depth brackets used: 6", 4", 2", and 1", depending on engine/trans/cab/bed length/2wd/4wd etc.
I asked driveline shop if there was a bearing avail that had an angled mounting flange, was told no - front shaft should be horizontal (straight) between t/case and bearing. This is exactly opposite of the factory setup. I'm wondering if maybe I need a 2" drop bracket??. Original 6" bracket had angled mounting surface for bearing, where 4" is flat (all 4" I have seen are that way.
Everything else is fine -- trans, trans mount, crossmembers, etc. I have checked/compared/checked again, rear springs fine also. Bought this truck from original owner, 6" bracket was riveted. Any chance Ford used the wrong bracket from factory?? I know I can shim the 4" to get the angle but what am I missing here?
Sorry for the long post, just dumbfounded. Any help is greatly appreciated.

 

I'm not too familiar with the parts in question, but I am doubting that Ford used the wrong bracket from the factory. I am not saying it's not possible, I just don't think that's the case.

If you had to "cut rivets" to remove the 6 inch bracket, then it was certainly done at the factory. If someone had replaced the bracket at some other time, you likely would have found bolts, not rivets, to remove the bracket.

I would want to know how the driveline shop determined the angles were wrong on the carrier bearing. Was it a reputable shop you dealt with? I know this may come as a shock but they are in the business to make money- they may have told you that the angles were wrong just to sucker you into more work.

If the bracket on your truck is wrong from the factory, it probably isn't the only one. Call your local Ford dealership, give them the VIN# for the truck and have them check to see if any recalls were issued for it. If the bracket is wrong it's possible Ford issued a recall.

You may also want to look in your owners manual- I would think somewhere in there, it lists what size bracket you need. If it's not in the manual, it could be on the ID plate, which should be located on the driver side door jamb, either on the door or the body.

Again, I'm no expert in this area of these trucks, but I fear you may have done a whole bunch of work for nothing. I am sure some others will chime in who know more than I do.

 

Sounds like you would have checked for this, but that really sounds like a bad U-Joint or bent propshaft. Are the ends of the propshafts good?

 

I had removed driveline and had all joints and bearing replaced then balanced. Only issue is angle, I'm not sure what is actually "correct". My discussion with driveline shops has been only verbal so far. They have a very good reputation, I am taking truck in Tues for them to evaluate. There seems to be very few similarities in the factory setups. Very confusing.

 

with the two piece rear driveshaft, the shaft should run straight from transfercase to carrier bearing, the u joint behind carrier bearing is where the angle down to axle is obtained. the carrier bearing is to support the longer driveshaft for the extended cab long bed trucks and is designed for straight through operation

 

Gee, I have the same shudder on my '93 F250. I'll have to go take a closer look at the angles & such...

 

fdude64 what you are saying agrees with what I am told is "correct. What is so confusing is that so many of the factory Ford setups are not done this way, but more of a continuous slope along entire driveshaft

 

The 96 4x4, 4 door, short bed I bought with 140k miles had the same shudder shortly after pulling away from a stop. Previous owner said it had it since day one and that Ford said it was normal. All of the U joints check tight and other than the rubber itself around the carrier bearing being sloppy the carrier bearing sounded and felt fine too. I just lived with it for a few more months.

A few months ago I had 1,800 pounds of concrete blocks in the bed. There was NO SHUDDER! Actually I was surprised at how smooth the jackwagon suspension was with all of that weight. And the PSD hardly even knew the weight was there.

Some internet research found someone saying that Ford says that up to 3/4" shim under the carrier bearing was acceptable if the truck was to be driven primarily unloaded. It couldn't find that statement again if I had to but I read it on the internet so it has to be true!!

I used a 4' level as a straight edge to observe that the front and rear halves of the driveshaft were not parallel. These were 'eyeball' measurements but if you take your time and get your head in positions so that you can make decent visual references you can get pretty close. I had three 3/8" shims cut in case I needed more than the 3/4" allowable. I picked up some longer bolts and nuts too. One 3/8" shim put the two halves of the drive shaft parallel to each other so I tightened everything back up.

I am happy to report that I am shudder free!! Now all I feel are my cobbly wooden tires as they start rolling.

Your milage may vary.

 

i have only had a few with the 2 piece shaft set up and they all ran straight to carrier bearing. what has ford told you about the 6" bearing having an angled mount? if there is a very steep driveline angle then maybe they angled the mount to relieve some of the angle from u joint behind bearing. there is a u joint at the transfer case where the yoke to help with the angles

 

I haven't checked with Ford, dealerships here seem to have young writers/techs that are unfamiliar/not too interested in these older trucks (based on past experiences). Just to be clear: my factory setup angled downward from t/case to bearing, then nearly straight to rear axle. I changed bearing drop bracket from 6" to 4" which created a continuous slope of entire driveshaft. Sounds like I may need to try 2" drop to get what seems to be "correct".

 

There are 3 different brackets listed for 1992 F250. If you can see a number on your bracket, it should read E9TA-4831-CA. That's the one listed for 155" wheelbase 4x4.
If you have that one, then it left the factory with the correct bracket. Unfortunately, I don't have any details on dimensions, so I can't help you out there.

 

Doug thx for the part # - just cleaned the 6" I took off and it is that # exactly. Shaft angle with that is nowhere near horizontal - I'm going to try and acquire a 2" Monday and take all 3 brackets with me to driveline shop. Thanks for all the responses, When/if I figure this out I'll post results. Keep any ideas coming

 

Problem SOLVED long ago: The 4" carrier bearing drop bracket AND a 1/4" shim under the rear mount of bracket and NO SHUDDER, even towing 8000+ lbs.