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Transmission time

I found this guy here in Houston on craigslist. he can build my 8" with a 370-380(he said there's a limited supply of gears for the 8") posi for 1000.00. and he also can build my transmission with a torque converter for 1400.oo. You should have heard him, "How much for a C4 overhaul"? The way he said it was funny! I think I'll give him my business. I really hate having to pull my third member out! :doh A big however strikes me, with that kind of gearing, am I going to lose freeway speeds and be turning a high RPM while going 70mph? Bear with me ya'll, I'm very new at this part of the restoration.

http://www.249drivetrain.com/
 
Dne':

It's time to step back a bit and decide what you want to do. The entire transmission/rear end thing has to be examined as a package. A nice C4 with a 3.0 rear end is perfectly adequate for most applications. 3.25 to 3.55 are also nice, but you begin to degrade mpg's and increase rpms at highway speeds. If you go with an AOD, then you want a 3.75-4.1 rear end. The overdrive of the AOD really helps out.

Now then...what do you want this car to do? Cruiser? Highway Cruiser? Track Car? Drag Car? Each of these will place you in a different tranmission/torque converter and rear end combination. You want the stall converter to be less than your typical cruising rpm, or you'll overheat the tranny without special cooling. If it is a drag car, you want your converter to be at the peak of your torque curve of your engine.

With a nice C4, 3.0 rear end, and a mild torque converter, you can bark the tires, have fun, and still get fairly decent mileage for a street cruiser. It's all about what you want to achieve and (of course) how much money you have.
 
Thank you Midlife!
a nice street car that will bark its tires would be just fine. Meeting up with my Mustang buddies and an occasional drive to Conroe to our lake home. A stock converter would probably be just fine as far as I'm concerned. I think I'll just go ahead and replace my pinion seal and just see what the rear end does when it's put back into action. I just don't want the motor turning 4k at 70mph. Actually, I could probably shop around and the have the transmission overhauled for even less. I look at the little c4, and just can't believe something so small can cost so much to overhaul. I'll continue shopping. It's not so much a money thing, just want a fair shake of what I spend my money on, knowing this Mustang is probably only worth 10k at best! lol
 
+1

I ran a C6 with 3:90 gear out back in my 71 and it was a pain in the ass to drive on the highway, even short distances.

If you are keeping the C4 do not gear it any lower than 3:00 maybe 3:25 at the most.
 
Exactly Sluggo!

You know what I'm talking about Sluggo! Can a good transmission person do re-gearing in a transmission to offset a rear end with high 3's?
 
Re: Exactly Sluggo!

"Sportbikechick" said:
You know what I'm talking about Sluggo! Can a good transmission person do re-gearing in a transmission to offset a rear end with high 3's?
Click to expand...

It can be done, but it is not cost-effective. You'll end up changing every gear in the C4, which will cost a whole lot more in modification costs than replacing the rear end with standard gearing. A new rear pumpkin should only cost you about $600 at most.
 
Re: Exactly Sluggo!

"Sportbikechick" said:
You know what I'm talking about Sluggo! Can a good transmission person do re-gearing in a transmission to offset a rear end with high 3's?
Click to expand...

Yes. But..........To achieve the driveability goal it would have to be geared beyond 1:1. (which is what overdrive is) With room for only three forward gears and reverse, you will suffer poor performance somewhere else.
The whole range of forward gears would have to be altered. Your options would be limited to:

1: All gears higher range. Higher range low gear would have slow acceleration from a stop.
2: Leave low alone and raise 2 and 3. You would lose torque between 1-2 shift and the car could bog.
3: Leave 1-2 alone and raise 3. Same outcome as number 2 only on 2-3 shift.

Problem is, any one of these combinations would be detrimental to the life expectancy because of slipping and load.
Two enemies of auto trans, slipping and heat.

If you want to cruise on the highway for more than about 5 minutes in August in Texas and don't want to go with an overdrive, go with the C-4 and a rear gear somewhere between 2:70 and 3:00.
 
Dne,

You need to start drinking more. You're thinking WAY TOO MUCH into this whole thing.

You currently have a 2.79 "open" rearend with a leaking pinion seal. Fix the seal, but leave the rest of the rearend alone. 8" rearends have been known to last FOREVER with minimal/no servicing.

You're unsure of the condition of the two C-4's you bought, but it's possible/likely that either of them may be in perfectly good working order. Install one of them and find out. If it's not working to your satisfaction, install the other one and try it. If it turns out that neither C-4 is working properly, then get one of them rebuilt.

While it's nice to install new/rebuilt items as the cars rebuild progresses, it WILL NOT prevent the car from having problems. In theory, you could be pulling the motor and trans out 2 weeks after the car is "done" to fix a rear main seal leak or some other annoyance.... these cars are NEVER done as there's always some little item still on the agenda.

Fix your 2.79's pinion seal, install one of the C-4's and cross your fingers. If the C-4 works out, great! Next winter pick up a numerically higher gearset (3.00 - 3.25), install it and give it a try to see how you like it.

My $0.02
 
Dave's advice is right in line with the way I have done my car. In fact I stuck the trans in and it worked fine but leaked. Later on I yanked it and had it rebuilt. The vacuum modulator valve they put in wasn't working and I thought to myself, why did I just pay for a rebuild so the trans won't shift. Anyway, as Dave suggested put together what you have and you can always upgrade/change things later. I'm still doing that with mine going on 20 years with this car...
 
update

I ran into a friend, not literally! which owns a transmission shop and he is going to overhaul my c4 for about 350.oo, and send the torque converter out to be made to go with my mild cam. Actually for the price, I'm having him overhaul both c4's! I mean, what the heck, Circle d was going to charge almost 1900.oo so this should be a decent deal. Plus he'll put in a mild shift kit or whatever. I'm hoping next week sometime to put my motor/tranny in! :pep
 
intall both at the same time?

I went ahead and let Tim the tranny man overhaul both of my c4's and the torque converter was sent out and "bumped" up a bit on the stall speed since the cam is not a super cam. Totalled 800 for all. Not a steal, but a pretty good deal. I'll just put the other one not being used on the shelf or put it on ebay or craigslist someday. If there is another restoration, it will already have a standard tranny.

My question/s are right now, to attach the tranny to the motor and install as a unit, or install separately?

If I install them together, How do I get to the torque converter nuts, or just tighten them when the motor is back in the car using the starter motor to bump the flywheel around, or at least tighten one so that the torque converter won't become recessed?
dne'
 
Rick and I tried to install his as one unit but it was too much trouble without one of those tilty thingys.

We had to split it up.
 
all I needed to know

Thank you Sluggo! I think that will keep things more safe by installing the motor, then the tranny later. tanks!!!! I see transmisson jacks for pretty cheap these days.
 
I was not sure you would approve of my non-technical terminology for the device of which the name escapes me.

Tilty thingy seemed "universal"
 
But I knew exactly what you were talking about, so it must be an accepted description of the preferrred tool for the application of installing a 289 sbf :pbj! :doh I'm sure "others" on this board would agree! :rofl

"Sluggo" said:
I was not sure you would approve of my non-technical terminology for the device of which the name escapes me.

Tilty thingy seemed "universal"
Click to expand...
 
I believe "load leveler" is the name for the tool that is escaping you'all.

Joining the engine and trans out of the car is a simple affair, actually much easier than doing so one piece at a time while installing in the car.

Hoist the engine off of the engine stand and lower it almost all of the way to the floor. Install the block plate and flywheel. Insert the torque converter onto the trans input shaft making sure it's fully seated. Slide the transmission over to the low hanging engine and line up the torque converter studs with the holes in the flywheel. Mate the engine and trans together making sure that the 4 studs on the tq. converter are aligned with the flywheel as you do so. Snug down the bolts holding the bellhousing to the back of the block. Using a breaker bar on the large harmonic balancer bolt, progressively rotate the engine until each of the four tq. converter studs are visible through the opening where the starter would bolt on. Install nuts onto these studs and tighten.

Install engine/trans as a unit and save yourself the trouble of trying to align/mate while working under the car.
 
"daveSanborn" said:
save yourself the trouble of trying to align/mate while working under the car.
Click to expand...

Hmmmmm, sounds like some of the times I have had while under a car.........
 
:doh decisions decisions! :cry I've got a couple weeks before installing~ guess I'll go to ebay and see what loadlevelers are going for. Thanks Dave!
dne'
 
Northern tool http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_19979_19979 $49.99

Without the leveler, you have a hard time controlling the angle. Even jacking up the rear does not help a whole helluva lot.

2_05_10_08_4_46_28_0.JPG
 
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