I would put a hundred miles on it & change the gearoil; if all looks good call it done.
Glen
Hello All- After many interruptions I have my GT6 back together and on the road again. I actually finished it at the first of June but I wanted to road test it a bit to be sure all is well. No problems so far and it's now a lot quieter than with the original unit.
I'll try to post three photos here of the original differential all apart- it wasn't quite what I expected but close. I didn't see any damage to any of the gear teeth, it's just the carrier that went. Made a mess of the brass washers too. I used the parts car diff that had the clean gear oil as the replacement. I pulled it apart too to check it out- everything looked perfect without a speck of rust anywhere internally. I just replaced all three oil seals and called it done. I think I possibly got lucky and now have a low mileage one. Externally it took lots longer to clean up the case than I expected, about three afternoons. I'm so happy again to be driving it- words can't express! Glen- Thanks again for all your advise and expertise.
photos-
https://photos.google.com/photo/AF1QipPdN9NCC54HW4-vw1GGpv81h-SVa2TYL6Izdg0L
https://photos.google.com/photo/AF1QipPy5hP6FPqbbuBhCalNr-6gGm7uGy4O7uisSpMc
https://photos.google.com/photo/AF1QipNFwLY7kkwpZpbytzobB9gw77vbHbu22ba1uLdI
Dan I would be careful about bearing selection, there are some real crap bearings on the market.
Once you get it torn down you can get the part numbers off of the bearings and we can cross reference to Timken if necessary.
Ideally you won't have to change the bearings, it's a bit involved, but we won't know until you get the thing apart.
The 1st step is to get a mesh pattern, if it's good then it's worth further investigation.
Glen
Glen- I finally got the time to get into it again this month... I have the two parts car's diffs out now, took a while as they were outdoors and I'm too old and lazy for cold weather work. I also had to get the leaf springs-suspension-wheels back in both body shells to where I can still roll them around. Right now I've got the broken driver in the shop, and in the process of slowly pulling it's diff out. So far so good. I drained the gear oil out of both from the parts cars and both looked great. One just a tad sludgey but the other looks and smells like new. I can see marks on the drain plug where it had been changed on the clean one. Looking inside the drain plug holes (with flashlight and tiny mirror- micro camera won't fit) I don't see any rust at all on either. Not much can be seen through that tiny hole but I sure tried.
When I get the broken one out I'll pull it apart first for practice. I have been waiting to order the bearings and seals just in case I ran across yet another diff but now might be the time to order them.
So- I see rebuild kits at multiple vendors and ebay. Six bearings/four seals and paper gasket. Possibly all are the same generic kit? I don't see a brand name for the bearings on any of them. Can you point me to any particular one with the Timkin bearings? Dan
Dan it sounds like there's a pretty good chance that you'll have the hard parts that you need.
I don't know if new axle/spyder gears are available, doubt it.
Hopefully one of the others will have good gears.
The R&P is the big issue, try to clean and do a mesh pattern check BEFORE you tear them down.
Not only will you know if they are good, you'll also know the pattern that you'll need to get when it's all set up with new bearings; setting up used gears isn't quite the same as new, used always have a well-established pattern and may differ slightly than the ideal.
Also the diff gears can fail from having too much lash/wear.
The axle gear thrusts break up/wear (later cars use some synthetic material junk, early use proper copper/brass), and the spyders have a dish-shaped thrust, selective fit for correct lash when assembled.
Also try to find Timken bearings, stay away from the chicom junk.
Good luck!
Glen
Hello Glen-
A long story and a question... No, after I saw the universal joints were fine I understood the problem and what probably happened. I'm fairly sure now that one of the small spider/sun pinion gears broke in half or just went to pieces. The free play-slop inbetween first and reverse and loud clunking made me first think a u-joint's bearings broke- but now I'm sure it's a pinion gear problem. When it happened I didn't hear any crunching of teeth. (just a loud bang) I loaded it on a trailer and brought it home that day- moving it slowly in first and reverse. Same when I brought it into the shop a few days ago- no crunching but lots of very loud clunking. So mabe all the broken bits has fallen into the bottom of the case if I'm lucky.
I pulled the car back out of the shop last week when I saw how unavailable diffs and internal parts are. I parked it back into it's storage building until I figure out what to do.
Yesterday I went out to a local British sports car repair shop/junkyard, and luckily(?) bought back two body shells ('71 and '72 GT6's) I had sold them two years ago. I had picked both cars really clean, and at that particular time figured I could get a complete rebuilt diff easy if needed. They were still listed as available then anyway.
So- now once again I have two used GT6 shells for parts. One of the two GT6's(the '72) I had drove 10 or 12 miles before parting it out about 20 years ago. Back then it was manly the engine/tranny I really wanted- but I remember the diff in it was nice and quiet. I'm hoping it will be a good donor now and not full of rust and wear. The other '71 GT6 I have no clue on the diff's condition, it's just "there". Never drove, and it also set for about 20 years after I picked it clean. Both cars have much lower miles on the diffs than the broken one, so that's one plus.
Right now I'm thinking I'll pull them all three apart this winter and try to build up one good one. I can take my time more then- and might get lucky finding more parts by then.
I can see replacing all the bearings/seals that are still available. The ring/pinion in one of the three will hopefully be useable- but I can buy new if not. (well, if available)
But the small spider/sun pinions and the bevel gears they run in- is there any hope for finding them new? Do they interchange with any other model you know of?
Thanks- Dan
Dan do you have it all apart & inspected?
If none of the broken bits got jammed in the ring and pinion and damaged it, it may be OK but 300k is a lot of miles on it.
A close inspection of the R&P gear teeth will tell a lot.
If the R&P is serviceable, it can be rebuilt, but it requires very precise setup and may be short service life due to the high mileage.
Glen
Well- no luck so far searching, and I learn yesterday there's nothing available from Rimmer either.
I wonder how practical and possible it is to repair what I have with used parts? From a junkyard or where ever I might can find them?
And does anyone know of another model/brand differential that can be made to work?
On my '72 GT6- A loud bang when making a right turn a couple weeks back... I'm thinking it's a universal joint bearing letting go at first, but after putting it up on jackstands this past week I see the problem is a broken spider gear in the differential. I can understand it too, having over 300K miles on it. It's the only part that hasn't been rebuilt or replaced since I bought the car in '75. So no complaints on the breakage- but a big groan because I already know finding a good replacement diff won't be easy.
As usual I'm open to any advice or suggestions. The only rebuilt ones I'm seeing listed online now are at Rimmer. I guess I could afford that, if there are no options here stateside?
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