The off-road guy will probably be able to quickly recognize the problem as they often deal with driveline issues (I used to own a Jeep and off-road frequently, and dealt with driveline issues too). Besides the u-joint phasing, you need to worry about the driveline angles (which imnezrider has mentioned time and time again) - driveline angles is not the same as u-joint phasing! Here's a picture I found on Hotrodders.com: How much longer was the T5? If the mount your mechanic made placed the transmission at the same height and had to shorten the driveshaft I pretty much would guarantee you the angles are not correct. This is something the off-road guy will (at least should) check, or it can be easily checked with a magnetic angle finder. Good luck, and keep us posted!
Illustration #1 is a no no ,dead straight kills ujoints. #2 is the correct deal as long as the angles are equal and not excessive IE 5-7* .
[wrong - wrong - wrong] And every one of those pictures show a 180* out of phase drive shaft (the kind that doesn't work/vibrates like a mother scratcher) [/wrong - wrong - wrong] edited, please ignore the above
Sorry Specialk you are in error on that. Got Engine Pro's picture post on page 6 of a stock driveshaft . The eyes of the yokes in the tube are always in the same plane. The drawings are correct in that respect. I've been in and around driveline shops since the mid 60s.
i was told that you have to have the trans/differential angles approximately 3º toward the driveshaft depending on the angle of the shaft. another consideration is that sometimes the angle has to be directed toward the side too. here's a good link: http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php another link: http://www.drivetrain.com/parts_catalog/drivetrain/driveline_angles_and_phasing_problems.html
today i took the truck to an offroad place. the guy looked at it and he told me that the driveshaft has to be "doglegged" and it's not. also the shaft is not centered in between some frame members. he also wants to check the yoke and make sure that it goes far enough into the output bushing which was also a concern of several people here. the third concern is the driveshaft phasing. we can see upon visual inspection that the phasing is off but we do not know if that can cause such a bad vibration. he called a driveshaft man but i got sidetracked and didn't ask him what the guy said. regardless, if the yoke is not far enough inside the trans, a new driveshaft is in order. so my hunch is that the driveshaft not being "doglegged" coupled with an out-of-phase driveshaft could be causing my problems. he also doesn't like the mount that my mechanic made because it's not wide enough to counter the torque. he has to make a new mount anyway in order to re-align the driveshaft. he's going to look at it again after he finishes another job and get back with me before he does any work. i don't want to be throwing good money after bad. does this guy sound like he knows what he's talking about? my greatest reservation is that he's only been in business two months! i didn't know that beforehand BUT, he was within limping distance and i can't drive that truck faster than 25mph. PLUS my plates/inspection both expired while it's been in the shop for over two months.... he seems to know what he's talking about and is a nice guy. he even gave me a ride back to my motorcycle which was parked at the other shop. how much out of phase can a driveshaft be before it will cause a vibration? do driveshafts have to be "doglegged"? clearly my differential is not centered and the driveshaft looks like it's perfectly straight from the trans to the rear-end.
If you can see a out of phase it is more the enough to cause a very bad vib. actually 1 or 2 degree out of phase will shake. If the diff center is off set the required angles needed for proper driveshaft operation can be obtained there and the pinion and trans can be dead straight in to each other in the horizontal plane.
I reckon tolerance on a high rpm shaft is measured in tenths of a degree. Vibration is a general term, as bearings/bushings have to be able to tolerate vibration frequencies & amplitudes resulting from rapidly changing loading conditions. As for doglegging, this is done to keep the driveshaft from binding; in effect, the driveshaft lags the torque of the transmission.
Ok I guess I've read enough !! 7 Pages and 129 posts and you tell us you have to drive this contraption 25 MPH or less or it vibrates like a DOG SHITTING PEACH SEEDS !!! You've got something serriously wrong here !!! We have explained more than enough times what is correct or what isn't correct. Now you post more problems you think that you might have like the yoke not being in the back of the tranny far enough to be into the tailshaft bushing !! Now it sounds like the cats you have working on this thing don't have a clue of whats right or wrong. I would suggest that you get this truck to somebody that knows what the hell is going on and please do this quickly before you puke the driveline outta this thing and get somebody hurt !! If you could take some pics of this mess and in detail maybe someone on here could help you straighten out your problem. I'm not trying to be a Prick but please !! >>>>.
If you can see it out of phase it is bad. Enough said. Wont work by design. Pull the shaft yourself and take it to a driveline shop and have one built or scrounge the junk yard for one. I cant believe a drive line shop would or could balance a shaft that is out of phase.
i couldn't believe it either. there's no sense in it. i don't think that the balancing guy is telling me the truth. he probably told my mechanic it was out of phase but my mechanic didn't want to have to fix it..... i can't do it myself because i only have my motorcycle for transportation. actually the new guy i think will get it done right. he's going to get a new shaft made, dogleg the driveshaft and fashion a new, stronger mount. i just gave an update and wanted to run what he said past you guys here and also had a couple more questions. if i were in a big city, i'd have taken it to a major 4x4 shop. regardless, i think this new guy can fix the truck.
If your truck has been in a shop for over 2 months for a vibration, you better find another shop. Something like your talking about should not take but a few hours at most to figure out. Pulling a driveshaft out and checking it over 15 minutes, pulling a t-5 30 to 60 minutes tops.
What the hell is "doglegging" a driveshaft? I've only been playing with cars for 40 years, but that's a new one on me. I've shortened a few 'shafts along the way, never had one come back to bite me. Bob
borntoloze: thanks, the guy who has it now is going to check all of that.... hopefully. at least he's on the right track. the other mechanic kept telling me to diagnose the problem and then he'd do "whatever i wanted". he'd then preface it with; "it's your money!". that was getting old.... i finally told him, "you are the mechanic, you tell me what's wrong." the angles should be checked with a full load?
Number (1) perfect in line is WRONG Number (2) is correct Number (3) is WRONG Number (4) is correct if the working angles on both ends are the same. Everybody seems to have an opinion on driveline angles. Most of them are based on speculation and guesswork. Universal joints are never meant to work directly in line without a working angle. I don't care if you flame me, facts are facts. Oh and what I just said won't make any sense now because I was refering to the diagram in post #142 and that picture has since been edited and the current diagram is now correct.
re the "dogled": the differential is offset from center. this new mechanic says that the trans is pointed toward the differential and needs to be straightened out which will cause the driveshaft to "dogleg" toward the differential.
@John - Mea Culpa - my recollection was absolutely wrong! It's why not looking at a vehicle and instead posting from memory is incorrect. - Mea Culpa redux I'm embarrassed to have posted the previous message and will edit it as soon as this apology is complete.
I read this whole thread and I'm in shock. I mean at least be good at what you choose to do as an occupation. This has all the makin's of a Reality Show. Me personally,, I'd get even with the first Mechanic.
Some mis-match in a drive train is always evident. That's why there are things like u-joints. I just never heard the terminology before, a new one on me. Bob
That's the problem with telling a mechanic what to do, it gives him the ultimate "out" when things go wrong. This whole angle thing would go away with a 2-piece shaft. Of course with the right yoke insertion into the T5. You may wind up having the front piece made up. A one piece shaft is viable, but figure on having a whole new one made up and balanced and getting the angles within reason. Bob
things just got worse. the second mechanic i took the truck to gave me some BS. he said that he has to change the angle of the trans to create more of a dog-leg to the differential because the new trans is longer than the other. i said "that would make the angle greater if the trans is longer". then he said that he has to notch the bellhousing to move the trans over! the trans is on the same line as the old trans just a few inches longer. then he tried to tell me that a new driveshaft will cost $450.00 because the u-joints i had were "cheap" and needed to be replaced bla bla bla... the guy is a bullshitter and doesn't know what he's talking about. i'm not going to let him notch my truck up and angle the trans. he would not just replace the driveshaft with one that is in phase. that's the biggie. so i have to go down there tomorrow and pick up my truck. where i'll take it i do not know. the first idiot mechanic tells me that he's going to file charges against me for failure to pay for service. so that's happening too. but i don't want to pay him for a half job and for screwing things up. i may end up doing so though. what a mess... my truck only drives under 25mph and the u-joints are out of phase. i gotta ride my bike out there, put it in my truck and drive back home! that's going to really stress those joints. this is insane....
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