Stupid question on overdrives

[Labrauer]

Can you have an overdrive on a standard three speed on the colume

transmittion? I keep hearing about the overdrives in these old cars I guess they have been converted to automatic transmittions? I have never heard of an overdrive with a standard transmittion.

Larry Brauer:confused:

[suntennis]

Overdrives have been around at least since the 1930s and work well on floor and column shift cars. The transmission case of an OD unit has an extra hole in it that is needed for the car to work in reverse. When buying an OD you need to make sure it includes the transmission.

[Young Ed]

No lots of cars back then had an available OD. Yes they were still 3 on the tree typically with an electronic engaging OD.

[greg g]

Over drives ( usually a reference to a top gear which allows the driveshaft to turn fractionally [usually in the .7 to .8 the lower the bettter] faster tha the crankshaft) come in a variety of styles. For our cars and trucks there were buitl in two styles for Chrysler by Borg Warner, but based on an in house design. The OD gear set is contained withing the transmission case. The differece being the earlier ones were basically manually controlled and the later were electrically controlled to allow upshift into and down shifts into the OD range. In this type the OD can work on 2nd gear as well as third to give what is essentially a 5 speed.

There are also Od units that are add ons, basically a planetary gear box that bolts between the trans and the differential. Volvo. Triumph, A-H, and some others, use this style.They are usually electrically operated and only when 4th gear is selected. They usually have a button on the shif lever and are selected and de selected throughthe switch or shifting out of 4th.

Most current 5 and now 6 and 7 speed automotive standard transmissions are OD in the top gear. Most moder automatic 5 or + speed automatics are OD in top gear along with the magnetic lockup of the torque converter.

Chrylser back in the days of the fuel shortage 70's converted a 4 speed manual into an OD by changing the gears of the 3rd gear set to be OD and modifying the shifter so that the trans shifted 1st, 2nd, 4th (the normal 1 to 1 position) and then 3rd.

There are other types designs out there as well.

For a couple of year Ford had an optional 2 speed rear end (made by Columbia) that served the same function as the OD in the trans, but held the function in the differential.

And HD trucks have used 2 speed rear ends for years.

The function of either or both is to be able to select a gearset which provides an optioin to reduce engine Rpms per mile travelled, reducing wear, and increasing fuel economy.

They are the reason why a modern car goes down the highway at 70 barely off idle, and our old cars run nearly 3000 rpms at 60. Also for the reason most folks have that based on the noise they think the engine is about to explode, 80% of that noise is probably atributed to the fan, but that seems less than reasuuring for most folks.

Forgive the TMI syndrome.

[old stovebolt]

Thank you for the very nice overview...

[busycoupe]

Thank you for the concise overview. I remembered some of it, but learned a lot.

Dave

[BobT-47P15]

Plymouth used the Borg Warner R10 overdrive with standard transmission

from 1953 to 1957 or so. (Someone please correct my info if needed)

I believe it is the G series. The number is cast on the trans case.

Column shift 3 speed. In a P15 and others it fits in the same space as the

non overdrive trans and therefore no modification of the driveshaft is

needed. Would be 6 volt electric thru 1954 or 55, then 12 volts later

years.

There is a manual available on the website listed in another post about

overdrive gear oil. The vendor is Fifth Avenue Antique Auto Parts in

Clay Center, Kansas. It is 40 pages long and evidently explains a lot

about the O Ds. Cost is $15. The seller does not use PayPal, and

lists a phone number of (785) 632-3450 from 9 am to 6 pm. They will

take a credit card via phone, fax or mail.

Here's a link to the 5th Ave web site........

http://www.fifthaveinternetgarage.com/parts/parts_counter_3.html#gearoil

Edited January 25, 2011 by BobT-47P15

[Young Ed]

52-56 Bob. 57-59 had OD with a different type of shifter.

[Jim Yergin]

There is a manual available on the website listed in another post about

overdrive gear oil. The vendor is Fifth Avenue Antique Auto Parts in

Clay Center, Kansas. It is 40 pages long and evidently explains a lot

about the O Ds. Cost is $15. The seller does not use PayPal, and

lists a phone number of (785) 632-3450 from 9 am to 6 pm. They will

take a credit card via phone, fax or mail.

Here's a link to the 5th Ave web site........

http://www.fifthaveinternetgarage.com/parts/parts_counter_3.html#gearoil

There is also a Borg Warner manual that can be downloaded for free from the the "Downloads" section of the main P15-D24 web site.

http://www.merc583.addr.com/mopar/framesets/softwareframeset.html

Jim Yergin

[hkestes41]

I will add that a 6Volt OD Solenoid/Govenor/Kickdown will live just fine on a 12Volt system. I have been running mine like that for 2 1/2 years with no problems.

[Labrauer]

This is a P15 Plymouth Special Deluxe Coupe that I am asking about. I have a three speed on the column and wonder how it works and where it plug or goes on the transmittion. If someone has pics I would like to see what I am looking at and know how easy it is to install. I don't know what transmittion I have but I will look tomorrow for some numbers.

Thanks for the information so far,

Larry Brauer

[Young Ed]

Larry it doesnt go on the trans you swap out the entire trans assembly for an OD version.

[suntennis]

The OD section is bolted to the back end of the transmission where a output shaft housing is now. I think the non OD and OD transmissions are the same length and have the same input shafts as long as they are MOPAR. In order for the OD to work, some wiring going to a relay and another switch is needed along with cable assembly to engage the OD.

[Alshere59]

A bit more than bolted on from the little I know. It has a shaft that extends from the overdrive into the tranny. I think the more accurate term is swapping the tranny for an overdrive. Adding implies you can bolt on a unit to the back of an existing tranny. That requires a machine shop. Ed has it short sweet and to the point. Install is the same as a tranny with the addition of the wiring harness (easy) and a an engage disengage cable. Like a manual choke but a bit more stout.

This may help. Read post 2

http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=23860&highlight=overdrive

Edited January 26, 2011 by Alshere59

[DJ194950]

some pics of differences between od case on left and std. on right. 1 more bolt hole, 1 more oil hole, and finally the one upper left is drilled hole with machined relief on lower edge for a steel tube to support shifter rail of od trans. a machine shop could make these changes but where would you come up with the steel support tube for shifter rail??

2 nd. pic is of overdrive unit and a stock mainshaft. the overdrive mainshaft is on about half as long and machined very different for od parts.

some parts will interchange between the trans: cluster gear and shaft,reverse idler and shaft, first/reverse slider gear, and rest of main trans parts if trans are of same era. later trans changed sycro stles and will not interchange.

easyest to find a complete od trans. use parts of your orginal trans if needed for repairs.

there is one on ebay now-a r10-g for $300. search for overdrive transmissions

hope this info help to clear up questions.

or did i open a can of worms??

doug

50 4 dr. project

49 suburban rodded

[1941Rick]

Great pics Doug.....made me go to the shop and check my transmission cases...mine are OD cases...I guess I was lucky and had a transmission that at one time was OD and had it removed...I stand corrected and the day is not lost as I have learned something.....

[james curl]

The overdrive case appears to have the cluster gear shaft hole elongated. I once had a Triumph TR 4 aluminum case cluster gear shaft hole elongated from running with bad cluster gear bearings. Had to have it bored and a 4130 steel bushing pressed in to take the cluster gear shaft.

[DJ194950]

what you are thinking is elongated hole is the recessed area cut on BOTH the cluster gear shaft and the reverse idler gear shafts holes. both shafts are cut for a moon shaped key to fit into flat cut into the side of shaft. the rounded part fits into the case recesses to lock the shafts from rotating

they are about 3/16 deep. shafts are driven in until keys are tight to case recess. this also locks shafts from moving forward and the tails shaft housing or the od section block keeps them from backing out.

good eyes, almost!!

later..dinner and tv time.

doug

[suntennis]

The purpose of the extra hole in the transmission case of a OD setup is to allow a spring loaded rod from the OD case to go to the sliding low-reverse gear. When the transmission is put in reverse, the spring loaded rod is moved by this gear and disengages the OD if it had been selected. Without such a setup, when the OD has been engaged, it would not be possible to back up.

[Labrauer]

Ok so what you are saying is that I have to put a new transmission in the car to have overdrive. What kind of transmission should I use for the 48 plymouth with the truion pin type u joints. Should it be one out of the same car year model or what will bolt up to a 230 ci engine.

Thanks for the input as always,

Larry

[hkestes41]

Larry,

You need to find an Borg Warner R10 OD from a later model Plymouth or Dodge. I believe Plymouth started using the OD in about 53 with Dodge using a bit earlier. Mine is from a 53 Plymouth Suburban. Was a direct bolt in swap. All the stock linkage hooked right up to the OD as did the drive shaft and E-Brake. Only thing that I had to do other than bolting in the OD was to install the OD cable (much like a hood opening cable) and wire the OD per the diagram in the manual (which is posted in one of the other OD threads currently going). I put my kickdown switch on the underside of the dash rather than the linkage since I have dual carbs but that was it.

Other than that you could use a S10 T5 using one of the available adaptors.

[BobT-47P15]

Here's a Borg Warner R 10 transmission.

It fits in the same amount of space as the regular non O D

transmission on a P15. Just put it in and hook it back up like

the original. Then add the things for the OD......wiring and

lockout cable, etc.

By the Letter G in the numbers, it must be for the 53-57 models.

Missing the solenoid, per seller.

Should work on the P15 models.

On ebay now.

Edited January 30, 2011 by BobT-47P15