Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: bozman on Friday,October 01, 2021, 10:29:52 AM
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I am near the end of my restoration and I sent the transaxle to be rebuilt. We replaced the synchro(s) and the synchro hub, along with other minor bits in the transaxle.
After installation we are finding that the gearing is backwards . . . 4 reverse and 1 forwards. Any insight into what part was put in backwards to cause this to happen?
Thanks in advance.
Greg
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Hmm, either you fit a R16 transaxle or they some how jammed in the ring gear on the wrong side. This is normally impossible as the mesh will be off due to the slight hypoid design. If they had done a contact pattern they would have seen the problem.
It will have to come out and be stripped again to sort.
Is it the original transaxle? Or?
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The 336 gearbox on my parts S2 has a type 336-56 name plate. I'm assuming the gearbox was operating normally before the rebuild?
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It is the original gearbox, and it worked as advertised before they took it for the rebuild. It has the 336-46 plate.
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I have read that the crown wheel was "relocated" from the original Renault R16 position to reverse the gearing to suit it for the mid-engine (thus reversed) orientation of the Europa. Does that mean all the parts are the same, just in a different location/orientation?
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Hi Greg,that 336-56 box I ‘gave’ you is good for S2 and S2 Fed,time to flush it and try it!Bruce.
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Hey Bruce, we are using the spare as a reference currently. With all the new parts and work into the original transaxle I really want to use it!
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Good luck, I am expecting to see it on the 10th at C&C.
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From what I can assume (until we have the transmission opened up) I think the crown wheel was installed on the wrong side. There seems to be a timeframe early in the 336 days (when used in an S1) where the crown wheel was on the opposite side. I think because mine is a 336-46, it is most likely supposed to be in the driver side, but it was re-installed incorrectly on the passenger side, or vice-versa. We shall see . . . .
You can see in the attached parts diagrams, one from the S1 parts diagram, and the other from the S1/S2 parts diagram that they are shown on opposite sides. Perhaps, since mine is a very early S2, Type 54 it has the earlier transaxle in it . . .
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All the Lotus-bound 336 transaxles received ring and pinion gears specifically made for the application. The “teeth” drove the other way and the ratio was 3.56 (not used in any Renault). With the arrival of the R17, they could use the standard Renault gears (3.78 ratio). The ratio change was why they had to use a custom 5th gear in the Lotus 365. Otherwise the 5 speed cars would have had a lower top speed than the 4 speed cars.
Long way of saying, no, they didn’t just flip the ring gear. I’m surprised that they would be able to flip it and not notice. The gears would not mesh well at all. Be hard to miss. Any chance at all they somehow fit R16 parts?
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The part numbers are the same. Early Europa printed material used R16 illustrations and were not always accurate.
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All the Lotus-bound 336 transaxles received ring and pinion gears specifically made for the application. The “teeth” drove the other way and the ratio was 3.56 (not used in any Renault). With the arrival of the R17, they could use the standard Renault gears (3.78 ratio). The ratio change was why they had to use a custom 5th gear in the Lotus 365. Otherwise the 5 speed cars would have had a lower top speed than the 4 speed cars.
Long way of saying, no, they didn’t just flip the ring gear. I’m surprised that they would be able to flip it and not notice. The gears would not mesh well at all. Be hard to miss. Any chance at all they somehow fit R16 parts?
I did purchase replacement parts for the original 336 trans from R16 shop, which are surely not "Lotus specific".
That said, the only transmission parts we bought from them were the synchro hub, synchro rings, bearings and seals. I can't think of anything that was replaced that is "rotation direction" specific.
But when I see images of (what appears to be) the same 336 case with the ring gear either the driver side and passenger side, it leads me to believe that they can be easily swapped. It may not mesh as well, but it seems like the only reason the rotation of the gears has reversed during the rebuild in my case.
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The only Lotus specific 336 parts are the ring and pinion gears.
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The only Lotus specific 336 parts are the ring and pinion gears.
Great. Thanks for the info and input. I will follow up later this week as we open up the trans.
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I don't want to sound silly, but how did you determine that the transmission was in reverse? Did you actually run the engine? Also, what engine is it?
I cannot figure out in my mind how the transmission could be assembled with 4 reverse and one forward.
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I don't want to sound silly, but how did you determine that the transmission was in reverse? Did you actually run the engine? Also, what engine is it?
I cannot figure out in my mind how the transmission could be assembled with 4 reverse and one forward.
I was not there mind you, but I am being told that the engine was started (for the first time after complete restoration) while the rear wheels were off the ground. It was put into 1st gear, and the wheels went backwards . . . and then (apparently) it was put into reverse and the wheels went forwards . . .
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This was an infrequent, but not unheard of, outcome with air-cooled VW transaxle overhauls. You just put the ring gear on the wrong side. Or, you fit a bus transaxle into a Beetle. It shouldn’t be possible with a Renault transaxle though. Interested to hear what you find when you open it up.
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Indeed, we have discovered that the ring gear has been installed on the passenger side and should be on the driver side . . .
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I never imagined a hypoid gear could be installed backwards.
Congrats on "the find"
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Before you take it further apart, please run a pattern check with bluing so we know how well the teeth were meshing.
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Interesting, If the gears are meshing correctly now , maybe that all we need to do on a renault gearboxes to get out of the four reverse ,one forward . :confused: It also would open up more donors.
dakazman
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I'm a bit confused here, not the first time. If the R16 336s can't have the ring gear flipped over, per an earlier discussion, how can the Lotus 336 be able to have it's ring gear flipped over? Supposedly, only the ring gear and pinion gear are different between the two transaxles with everything else remaining the same.
As an FYI, while taking a Manual Transmission class at my community college, I tried to flip the ring gear over to the other side as an experiment. At that time it did not look possible since no matter what I did, I could not get the pinion gear to mesh with the ring gear. Perhaps I didn't try hard enough. I really would like to see what your shop did to make this possible.
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I would argue that the ring gear can be flipped over, because that is exactly what we did (incorrectly) the first time. I am asking if the meshing was properly checked the first time around, but I can confirm that there is space for ring gear and differential to be swapped to either side.
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Always known there was the room but the gears are not supposed to mesh properly if the ring gear is flipped. Absolutely you can shove them together and get the "correct" freeplay but you shouldn't get a proper mesh.
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She is home with me now. I am sure they didn't check the meshing initially, which has me concerned about what other corners were cut.
Anyway, it's now my turn to make this right. Thanks for all the input!
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It's not really the 'transmission' that has 4 reverse and 1 forward, it is the 'differential' that has the ring gear flipped, so the engine and transmission are spinning correctly, but the diff makes the wheels go backwards. Of course, in this case, the transmission and differential are integrated, but conceptually they provide separate functions.
Interested to hear how this resolves, because I had always heard they just flipped the ring gear. Of course this was casual talk, I never had anyone with Collier's level of knowledge to point out this was not possible with a slight helical cut.
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Here's a '67 article on the Europa in Renault UK's own in-house publication:
http://lotus-europa.com/literature/Autoworld-Jan-Feb-1967.pdf
Regarding the gearbox it says:
"The gearbox retains the standard ratios of the 16 saloon, but new final drive gears, cut to rotate the other way when installed 'backwards' in the Lotus, give a slightly higher drive ratio of 3.56 instead of 3.77 to 1.