Hello everybody I am working on a 246 Dino and there is a lot of movement in the diff output flanges,I am assuming that this is not right. I have to pull the halfshafts to replace the CV boots and I was planning on replacing the diff seals since I was there. I do not know how bad they leaked for the owner, but I had it up on jack stands and running in gear to warm the fluids and the diff outputs were wobbliling around quite a bit, and leaked a big puddle in 15 minutes. Am I kidding myself into thinking that while I am in there that I can just adjust the bearing preload. Or is that a fools errand and the fact that it is that lose can only mean that the bearings are shot, even tho the car only has 47,000 miles on it. I would appreciate a little feedback from everyone with more knowlage on the dino / 308 diff. Another issue the car has, is the transmission falls out of reverse and first (not jump) and all of the gears pretty much bottom out on the gate, like it has too much travel. But there does not appear to be any real wear on the linkage ( u-joints, and shift lever bush ) any thoughts ? Darryl
Darryl, Not sure about your differential bearing question, others I am sure can help. With regards to dropping out of gears, sounds like the detent spring/ball bearing in the gear change rods may not be aligned. Also sounds like you gear forks may need re-setting. Attached at bottom of path are a series of photos on how to set this up. http://ferrarichat.com/forum/showthread.php?t=226569&highlight=Gear&page=3 Suggest you wait or some other suggestions before taking the gear box plate off. Although not a difficult job, it is time consuming and you will need to replace the gear oil. Kevin
I've been here and learned the hard way. Its a while since I did it but as I remember there are three critical stages. First you must lock up the diff mechanism - there is a diagram in the book with a special tool - I did it with a washer of the correct size that jams the output shaft against the diff housing, this means that when you turn one output shaft the other turns the same way. Second you need to be able to turn the drive shafts without the crown wheel engaging with the gearbox - I had a dummy crownwheel with no teeth on it machined. So now I could reassemble and turn the shafts and diff assembly freely. This is where I went wrong - I put the crown wheel on the wrong way round; expensive, dont do it. Thirdly you need to apply the correct load to the bearings. I did this with with free running nuts on the studs that clamped up the bearings without a shim.The torque load was applied with a weight on a pulley connected to the crownwheel side output shaft. There is a photo of this on another thread. Finally, measure the gap and get the shim. Its straight forward but it will be difficult to do on the car (what isn't!) You are welcome to borrow the dummy crown wheel.
Good morning Darryl I just finished doing the diff and gearbox on a 72 dino 246gt. This is not something that can be dealt easily in the car. You can remove the top of the diff if the exhaust is removed. This differential is dead easy to set up though as you are not dealing with pinion bearings and crush sleeves. You can remove the crown gear and replace the bearings pretty simply if that's what the play is from. Although if the movement is both axial and radial that is most likely the cause. Don't let the low mileage fool you. The bearings are most likely pitted and worn due to exposure to moisture from lack of protection from the gear oil. In other words the oil drained off from sitting, leaving the bearing surfaces to rust. Good luck
When bearings are that bad, you can really hear them while spinning the wheels and put a mechanics stethoscope to the housing. You will know. Regards, Alberto
WOW You guys are on top of it, Thank you everybody for all of the good and helpfull info, I suspected as much about falling out of 1st and reverse being do to the spings and balls being possibly missing or wrong. And lots of good info about the diff bearings and seals, I have been reading thru the post about the diff seals. All of the different parts supplyers seam to have problems with that seal ( correct ) I am still a little unclear as what to use. I will keep you all updated as to what I find when I get in there. Darryl
Darryl, Others are helping you on the pre-load. However, thought a few pictures on sealing may help. I did this back in 2009, before I started taking copious notes. Amazing how easy it is to forget what was done. I also did not make a note of where I bought the new Vitton seals from. Note the sealant in the splines. I have done plenty of miles since and no leaks or trouble. Kevin Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
