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Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: JMOUL on July 02, 2025, 09:24:21 PM

Title: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 02, 2025, 09:24:21 PM
I recently had the engine & transmission rebuilt on my 58 Series 62 and seeking some expertise regarding the transmission.  Prior to the rebuild the transmission functioned fairly well, however the shift from second to third was a bit sloppy an a bit of a jolt.  Post-rebuild the transmission functions very smoothly.  The shift from 1st to 2nd is silky, as is 3rd to 4th, but while the shift from 2nd to 3rd is no longer as prolonged it still happens with a bit of a jolt (not smoothly like the other shifts).  TV rod adjustment and the addition of fluid thickening by the shop has helped a bit but has not resolved the issue.  The response I'm getting from the shop is this is the best they can get it based on parts that were available (?).  Can someone advise me what components / part (s) would possibly need to be replaced to ensure a properly smooth 2nd to 3rd gear shift, or what else could be done to improve the 2nd to 3rd gear shift?  Thanks very much.
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: Roger Zimmermann on July 03, 2025, 02:02:32 AM
You will never get the 2 to 3 shift as silky as the other shifts. 1 to 2 and 3 to 4 are purely hydraulic; 2 to 3 is mechanical; some transmissions are better than others, but you probably will always notice it. The 2- to 3 shifting at my own 56 car is rather hard when cold and is getting better when the oil is warm.
You may play with the TV rod adjusment but don't expect miracles.
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 03, 2025, 09:17:33 AM
I appreciate your feedback...thank you.
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: dadscad on July 03, 2025, 06:56:55 PM
Your factory shop manual will have the step by step instructions to properly adjust the TV rod to obtain the optimal shift performance. There are no shortcuts to  obtain the proper adjustment. Once the procedure is completed, you can fine tune the shift quality by turning the adjustment nuts by one nut flat at a time. Adjusting the nuts to pull the TV rod to the front away from the firewall will delay the shift point to shift at a higher RPM/MPH. Adjusting the TV rod towards the firewall will quicken the shift point. By that I  mean at a lower RPM/MPH. Adjustments made in small increments will zero in for the best shift performance.
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 04, 2025, 09:59:36 PM
Thanks for the great explanation.  I may play with it a bit more when I get it back from the shop.  Shift point currently aren't too bad...just thought the 2nd to 3rd shift was a bit abrupt, but may have to live with that based on the comments noted above.   ;)
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: TJ Hopland on July 05, 2025, 10:14:18 AM
If I'm thinking of the correct model this transmission is basically 2 2 speeds inline so 1st is lo-lo 2nd is hi-lo 3rd is lo-hi 4th is hi-hi.   That 2-3 shift both sections have to shift at the same time so there is more going on than the other shifts where its just one section shifting.   I have been driving a 57 a bit recently and a majority of the time it feels like a 2 speed, I don't even feel those other shifts.  I would not say the one I feel is abrupt, it feels just like the later THM's its just by comparison to the other shifts it stands out. 
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 07, 2025, 11:11:18 PM
Another transmission related question:  My car is in the shop now for some post-rebuild adjustments/warranty work.  It began leaking transmission fluid on my garage floor (rebuild is 6 mos old) and the shop is saying it is a rubber seal between the transmission dipstick tube and the transmission case which is leaking (I assume all new seals when rebuilt, so redo).  They indicated that with these older transmissions when they've been sitting parked for any length of time the fluid will drain from the torque convert into the pan, essentially causing a bit of an overfill like situation and that it will then leak out of the point between the dipstick tube and the casing (in other words, get used to it).  Is this true?  Has anyone else experienced this?
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: Roger Zimmermann on July 08, 2025, 03:22:44 AM
If the tube's end is a bit damaged (dent, out of round), when fluid is draining from the fluid coupling, the level inside the case is getting higher and oil can leak at the oil filler tube. If the tube is in a good condition and the O ring is in a good shape (after 6 months it should if it was replaced), there will be no leak at this place.
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: dadscad on July 08, 2025, 07:26:07 PM
I don't know how the 58 tube is designed to mount in the transmission but I have found that on my 63,if the dipstick tube doesn't fit very straight into the transmission case, it will seep fluid if sitting for a while. Probably because of wear or as Roger mentioned slightly out of round. I have replaced the O'ring more than once but adjusting/bending the mounting bracket tab so the tube would sit as straight as possible in the case was the cure for my car. Hope you find success.
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 08, 2025, 09:52:31 PM
Thanks so much.  I will share this with the repair shop.  :)
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: TJ Hopland on July 09, 2025, 11:16:46 AM
How much fluid leaking are you getting?  Like enough that the puddle is creeping out from under the car?  Or just spots?   I have not been able to get the car I'm working with on a lift to see for sure but I'm thinking mine is only leaking bad when sitting so maybe it is a level rising thing too?
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 11, 2025, 10:07:33 AM
It's not just a few spots, but not enough that there's a river of it coming out from under the side either.  The first time I noticed it I cleaned it up and put a piece of packing paper underneath to better understand the volume.  I'll try to post a pic of it (paper was under the car for a week...granted it will spread more on the paper but you get the idea).
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: Roger Zimmermann on July 11, 2025, 12:18:56 PM
And that leak after a rebuild? Something was not done properly, evan if you'll never will have such a transmission leak free, but drops, not a lake...
Title: Re: 1958 Series 62 Jetaway Transmission Question
Post by: JMOUL on July 12, 2025, 10:48:36 PM
I think the paper makes it look worse as the fluid wicked outward on the dry paper.  The darker wet area of the paper is more the size of the puddle.  The shop seems to think the o-ring on the dipstick / filler tube is the culprit.  Why this failed in 6 mos and only about 300 miles is a bit concerning (i.e. improperly installed during rebuild or never replaced?), but that's where it's at right now.