40-2a Transmission 1.258

TRBenj wrote: I do have remnants of one of those kits around somewhere... but I do recall the claim that my spare tranny that came from a 89 was actually a newer replacement... so unless I can verify the year we probably wouldn’t solve the mystery with 100% confidence. Plus I have no spare time.

In 89 the ID tag said to use 20W20 oil in the transmission and they had a little sticker that went over those words that said to use Dex when the recommendation changed.

Or was it Dex then 20w20 then back to Dex again so there were multiple decals

90 and later..............beats me, but the tags changed early on and didn't need the little sticker any longer

Dex 3 didn't exist before 1993 either so that'll help narrow things down depending on what your tag says   


Edit ..............A little search found tags with 4 different recommendations at various different times so the tag probably won't exactly be helpful to figure out your year.

Cold man, real cold, and snowy

KENO wrote: 8122pbrainard wrote: KENO wrote: I had somebody else in mind with my comment Joe You know plenty about transmissions, he only thinks he does..... right Pete No Ken, you have done a great job with correcting me and I thank you for that. "Our own self-love draws a thick veil between us and our faults."       Lord Chesterfield It sure would be nice if you didn't need that correcting

Yes, it would have been nice if I didn't need correcting but I understand that we all need to be corrected at times. I also understand the needs of some to satisfy their our personalities.

Thanks again.

here is a picture of the tag from my 2006 216, 330 Excal

I do have remnants of one of those kits around somewhere... but I do recall the claim that my spare tranny that came from a 89 was actually a newer replacement... so unless I can verify the year we probably wouldn’t solve the mystery with 100% confidence. Plus I have no spare time.

8122pbrainard wrote: KENO wrote: I had somebody else in mind with my comment Joe You know plenty about transmissions, he only thinks he does..... right Pete No Ken, you have done a great job with correcting me and I thank you for that. "Our own self-love draws a thick veil between us and our faults."       Lord Chesterfield

It sure would be nice if you didn't need that correcting

‘Gearhead’ = JoeinNY. Love this stuff

TRBenj wrote: How about the gear tooth count Joe... can we infer the ratio that way (29/23) or is there more to it than that? Lots of other variables like tooth design and pitch but maybe they all cancel...

multiple edits as I think about this...

Getting those other variables right to make the transmission quiet, reliable, package correctly, etc... can get complicated but one gear to another direct contact - evenly spaced teeth the math is what it is and it's easier than spelling.    

Pick a couple coprime numbers for the teeth so they don't wear into a pattern get the ratio close-ish tell the customer that it is what they asked for and ship it..

32/26 (or 16/13) will get you 1.23(1) but share a factor of 2 so in theory could have some wear patterns develop
39/31 are 1.258 and share no factors
29/23 are 1.26(1) and share no factors

Well then maybe you wanted to keep the bigger driven gear the same and

If it weren't for the transmission that was linked that was labeled 1.23 and has clearly 1.26 I would think they had tried all three sets of teeth numbers at one time... but that one has me think there is fudging to be going on.   a Reason to switch from 39/31 to 29/23 at one point might have been an introduction of another gear ratio in that family (1.52) of transmissions and wanting to keep the smaller gear the same

35/23 will get you there sharing no factors
47/31 will also get you there but maybe no space for 47 teeth in that transmission?

If you wanted to keep the bigger gear the same (which don't make no sense to me because I would want a bigger output shaft for that gear to go on and then I would need two gears anyway so I wouldn't think it would be that way, the numbers here would favor the 1.26 starting gears....

39/25 is 1.56 which is a stretch for 1.52.... 39/26 is 1.5 but not good for wear
29/19 is 1.526 and looks good for wear

JoeinNY wrote: Well let's leave me and my spellificatin out of this..

I had somebody else in mind with my comment Joe

You know plenty about transmissions, he only thinks he does..... right Pete

Well I actually got kens link to open and those gears are in the one piece housing and labeled 1.23 - so probably just a bunch of lies straight from the start. The new theory I am going with is pcm decided they wanted a transmission that allowed them to run a 16 inch pitch prop at the same rpm as a 13 inch pitch prop.   They mathed it out to 16/13 = 1.23 stuck it on the side of the trans and never looked back until guilt or the law caught up.to them and they had to make it right...

Canuck-Surfer wrote: Booya! And here I was thinking I was special because I didn't have a 1.23!

You must be "special" to somebody

Booya! And here I was thinking I was special because I didn't have a 1.23!

29/23 = 1.261, not 1.258

Did PCM lie twice or is it not quite as simple as counting teeth? We may need our resident ME/pump designer/transmission rebuilder to check our math (and method).

Here's a PCM manual printed 9/99 courtesy of SkiDim (free download)

On page 1 it's a 1.23 to 1 ratio and on page 2 it's a 1.26 (or a bigger reduction 1.52 version.)

Go figure   

link

I have been following this thread and decided to check the transmission tag on my boat. I am the original owner of my 2006 216, 330 Excal with the factory original, undamaged prop. I was surprised to find out I have a 1.26:1 ratio transmission. I am not sure what to make of it but the boat continues to perform flawlessly with 475 hrs.