'motor home' gear vendors OD?

[Midnight_Rider]

Ran across a CL ad for a GV/727 out of a motorhome... worth pursuing? Assuming this might not work in a 71 B-body application?

[Kern Dog]

Those are just fine. It Probably has a fixed yoke. I was told that the fixed yoke is held on by a large nut. Once off, the GV has a splined output shaft similar to a GM Turbo 400.

What you may find annoying about the GV:

The speedometer drive exits the case at about the 10;00 position. Not sure about the 71 models but in my 70 Charger, I had to run either a 90 degree adapter or beat the floor so a regular speedo cable would fit.

The extended length results in a shorter drive shaft. Not as big a deal in a long wheelbase car. In a 108" wheelbase Cuda, Duster or Demon, the driveline angle gets pretty steep. In the 117" Charger it wasn't that bad. Your 2" shorter but still okay.

The .78 overdrive is not that great.

The crude electronic box mine had was a pisser. It was supposed to UPshift to OD around 47 mph. It was not consistent. Also, it rarely disengaged as I came to a stop, resulting in me being in 1st gear overdrive, 2nd gear overdrive and 3rd gear overdrive unless I over-rode the electronics. Sometimes it would stick in OD too.

[Bobs69]

I bought that unit brand new and if I could do it again I'd choose a manual.

[Midnight_Rider]

Thanks for the replies.

If I do end up going with a 727/GV combo, I'd prefer to do the shorty tailshaft setup like SMR has here:
http://smrtrans.tripod.com/smrtransmissionsintro/id33.html

However, I only see the $3k kits including the GV unit... so I'm guessing the short tailshaft section is unavailable separately. The pessimist in me also thinks that even if it is, there will be some small difference in the older GV units that would prevent if from bolting up to it & working properly.  Guess the next step would be to contact SMR and/or GV directly and ask.

[Midnight_Rider]

I bought that unit brand new and if I could do it again I'd choose a manual.

I am considering that option also. My car is a project and needs the driver's side floor pan replaced anyway, won't be any harder to put the hump in.

Thought about the OD 4 spd gear kits from Passon. Aside from the wide gear spread it has a few things going for it:
* bolts in using stock factory parts
* keeps stock factory driveline angle
* infinitely variable stall speed

Wonder how a GV behind a standard A833 would work out?

[Kern Dog]

You'd still be dealing with some of the same issues that a 727 install would bring you: Speedometer cable clearance, cantivered GV unit and driveshaft angle.
For the money, I'd keep saving and then just go with the GM based 4L60E/700R4 from Silver Sport.

[Bobs69]

I never had any problems with the angle.  There is no vibrations caused by the unit.  My drive-shaft was high speed balanced and I didn't have to do any other diagnosing or fiddling to make it right.

High speed balancing is a must and they tell you that.

[469 runner]

If you want to use the shorter extension for the GV you will have to modify the torsion bar crossmember.  Not exactly bolt-in and would require sheetmetal work.  Though, it would be a better driveline angle for the driveshaft.

[Midnight_Rider]

If you want to use the shorter extension for the GV you will have to modify the torsion bar crossmember.  Not exactly bolt-in and would require sheetmetal work.  Though, it would be a better driveline angle for the driveshaft.

Thanks for posting the info. Helps me make informed choices. Which potentially saves me money

I see your avatar mentions a '68... assuming you saw I am dealing with a '71 RR. I have read that will make a difference when dealing with cutting the floor with an A518 OD, but guessing not so for the GV tailshaft.

[469 runner]

Yes, I believe the undercarriage dimensions are nearly the same on a '71 B-body as a '68 B-body. 

[Midnight_Rider]

If you want to use the shorter extension for the GV you will have to modify the torsion bar crossmember.  Not exactly bolt-in and would require sheetmetal work.  Though, it would be a better driveline angle for the driveshaft.

I wanted to quote this again to add some more info, and hopefully get some more info (as am a Mopar noob).

I emailed SMR asking for info re: the shorty tail shaft unit they show on thier website. Below are my questions & their response:

Hello,

I am exploring my overdrive transmission options for a 1971 Road Runner
project car I recently acquired.

I am interested in the "shorty" tail shaft for a 727 TF you show on your
website. Have a few questions.

1) will the shorty tail shaft allow an older Gear Vendor OD unit to bolt
up to it without issue? I have an opportunity to buy one locally if so.
Number on unit is GB C6B.

2) will the shorty tail shaft package be a true "bolt-in" for a 1971
Road Runner? i.e., no torsion bar crossmember cutting?

3) is the shorty tail shaft available for purchase separately? If so,
how much does it cost?

Thanks in advance for your time & trouble.

- Doug

---------------------------------------

Doug:

Thanks for your interest in the premium quality transmission products of SMR TRANSMISSIONS and CONVERTERS.

The "Shortie" overdrive only fits the '70 and older "B" bodies. Unless your model has the removable short type crossmember transmission mount without the torsion bars going into the removable portion, the Shortie overdrive unit lands immediately over the later style crossmember with the torsion bars through the one piece unit.

In either case, we do not sell the "Shortie" housing and shaft separately.

Regards,

Pat Storey


My question pertains to the bolded part, the crossmember. I have what I thought was the crossmember I needed, which has 2 bolt holes on each side & doesn't intersect the torsion bars. I believe it is around 18" or so between the outer bolt holes. Do I have the wrong part? Does anyone have a pic of the one I need or the "one-piece unit" that has the torsion bar go through it?

Thanks in advance...