I’m in central Ohio and have had my original trans rebuilt - still having issues / in high gear , it sometimes allows the engine to free rev with no power going through the trans to the rear wheels . Because of the age of the trans , and the lack of qualified rebuilders (though it was redone) it has been suggested to retrofit a 700R4 modern trans . I am not a purist , but would still like to retain the original trans .
Imput either way would be greatly appreciated .
Thanks
When that occur, do you think the transmission is getting like neutral or does it shift back to third gear? When warm, if you manually shit to low, do you get the 2. gear?
The trans feels ALMOST like neutral - it’s more like a slipping clutch / and the car will not do more that 45 mph without “free reving†- if I slip it down one gear , the gear engages , but shifting back to high gear does not always allow the trans to perform normally
I’ve learned of an adapter that would allow replacing the trans with a 700R4 / modern performance , warranty and any transmission person can work on it - it’s very tempting . I’ve had issues with this trans for years .
It could be that either the front or rear sprag is not holding. At distance, a diagnostic is not easy. Those transmissions are working well when all the small details are right.
Right now, I'm overhauling a '59 Cad transmission which was reworked a year ago in Germany. Up to now, I saw 2 or 3 errors...
Fitting a 700R4 will require more than an adapter. Consider the rear transmission mount location, drive shaft length modification, and a carburetor linkage modification/addition to operate the 700R4's shift cable. The shift cable adjustment and correct amount of movement as the throttle is opened and closed is absolutely critical to the longevity of the 700R4. The 700R4 also has some inherent weaknesses, so use one that has been overhauled with updated parts or get the one you use overhauled. Your gearshift indicator will have to read PRNDL instead of PNDLR.
For what you are going to have to spend and change I think you would be money and time ahead having your tranny fixed (by a different shop), your trans should be solid and reliable when right.
Having said that, I have a beefed (without a shift kit) 700R4 behind the 472 in my '35 Cadillac and it works well. Just make sure you get that cable adjusted right using the proper aftermarket carb attachment piece.
I had the same trouble with my jetaway ,, slipping in reverse.. I installed a 700r4 . not many miles on it yet , but it seems to be working well.. it was a lot of work... I already had the trans left over from another project...
Gene Harl clc22406 rgeneharlemail addresses not permitted
I'd consider cost. The parts are still available for yours and know how is there but getting scarcer, and they can be made to work. Even if they have the know how some shops do not want the hassle of chasing obsolete parts. I had to source for mine, a task I was not wanting.
If there's a major problem, it may run into the thousands to correct and you're probably break even with conversion territory at that point. And you have the task of finding someone to diagnose properly.
You might consider to find a "good" used '60 trans and do a swop. Cheaper but also risks with that.
Even if you convert, you still have the ability to go back.
I have seen a 1959 Cadillac with a TH400 trans and that may a better way to go. It is a real nice heavy duty trans. Everyone still works on them.
Right, another thought.
There are shops that do nothing but old transmisions.They would not need to learn on your transmision. I'm sure they come with a warranty. Look in Hemmings Motor news,under Services offered . When right,Jet Aways are bullet proof. Ken Perry
I learned of the adapter (actually a complete kit) from a friend who did a 60 Pontiac w a 400 turbo . The kit comes with all of the proper parts to make the change . And yes , I will retain the Jetaway and the conversion back is all parts replacement . My 60 trans has been “rebuilt†twice in the last 5 yrs , and I don’t think I have put 1000 miles on all told . The 2nd rebuilder will rebate everything I spent on the Jetaway (R and R and rebuild) and pur all against the brand new 700R4 and all the accoutrements - including the PRNDL indicator . But it IS pricey , $5500 done . Another $3-4 outta pocket .
Lotta wisdom on these boards , so I appreciate everyone chiming in â€"- still need to decide what to do , be an easier decision if I had a trusted “old trans guy†here in Central Ohio .
Jimi , are you sure there is no competent trans shop near you ? You can probably run a computer far better than I can , so perhaps you have researched it thoroughly. Now if I were in your position , I would post on the AACA forums. Member density in your area is high. It is a huge organization , and I spend a fair amount of time there. Certainly for my old junk out of the '20s , the support is greater. Many current and retired automotive professionals there , as here. It is just a much larger club. I hope you are running well soon ! - Carl
Hi Jim,
What live city do you live by/in? Maybe someone on the forum could recommend a trans shop by you. Or is there a Club Chapter close to you that may be able to recommend a shop.
Just a thought,
RS
Hello Jimi,
"But it IS pricey , $5500 done . Another $3-4 outta pocket."
Do I understand your post to mean that you are contemplating spending $8500 - $9500 on converting from a Hydra-Matic to a 700-R4?
While the controlled-coupling Hydra-Matic can be a bit finicky, and there were some early production issues, I think that by 1960 (if not earlier) the transmission was fairly reliable.
I have a '56 and a '59 transmission in my garage now. I plan to use these for educational purposes, and I have a lot of research ahead of me, but I think that if you do a few days of research, you should be able to find a competent rebuilder of your '60 Hydra-Matic for much less than the apparent - as I understand it - cost of conversion.
Respectfully submitted,
Christopher Winter
Thanks everyone for your input - I have had the trans rebuilt twice in 5yrs (the 1st one still leaked and didn’t shift properly) and the 2nd is my current story . Both times they were rebuilt by supposed “craftsman who have been doing these transmissions for years†, I live in Columbus and have several friends that own shops - between them , and my own research , I’ve found very few .
With a different trans, you need to reconsider a proper matching
rear axle ratio. A 3 speed is straight thru 1:1 in high, but that will
be turning the engine much faster than it need be. The additional
torque multiplication of the torque converter allows an engine and
gas saving lower ratio axle. A TH400 is truly bulletproof, cheap,
and has no tricky carb cables. The vacuum modulator is ideal for
responding to engine load.
An overdrive 4 speed will want a higher axle ratio, but if your axle
isn't high enough, you won't be able to use the overdrive. The
hookup is more complicated, expensive, and will likely need some
extra strength parts to be reliable.
Some like the old Hydro. I had several cars with them in the late
50s, early 60s, and they were all very troublesome both in response
and reliability. Maybe its the way I drive, no problems with a 400.
good luck, Bruce Roe
Some well known transmission parts sellers have a hit and miss with the metallic seal at the oil pump cover. A friend of mine was also the "victim" of such undersized seal. Have a look at this interesting story:
http://www.photopaige.com/edscars/60caddy/CaddyWebSitev2_files/TrannyRebuild2.htm
This report helped me to better understand those transmissions and repair them properly.
Another friend of mine who is a competent mechanics overhauled his '57 Jetaway. When the car was again on the road, he complained that sometimes the 4th range is gone, similar to your experience. I told him that the front unit coupling may be the cause. I was there when he removed that front unit coupling from the transmission and, indeed, the aluminum cover was cracked because he did not used some tools to retract both exhaust valves while extracting the cover. By removing the cover without the tools, the valves catch the groove for the large snap ring; adding more force to extract the cover damaged it.
Unfortunately, there is just one method to see if I'm right: remove the transmission from the car.
Great info ! Much appreciated !! I’ve decided to mull it over for a couple of days , though I’m inclined to do the 700R4 / the positives are hard to overlook . I’ll post after , WHATEVER I do is done and my impressions .
Thanks again !