TD transmission in a 712 vs a 710?

[audiocontr]

I'm giving some thought to buying a 712 with the stock transmission. I currently have a 710 with a TD transmission. My question is would it benefit me to swap the transmissions? Returning the 710 to stock and adding a TD to the 712?

Right now the TD on a 710 is a little strange. The gearing isn't great for around town driving and i rarely have the truck at a speed that makes 5th worthwhile. I remember reading that the benefits of a TD transmission in a 712 are significantly better than in a 710. Would like to hear of anyone's personal experience.

I've tried a search and was unable to find what i was looking for.

[Jim LaGuardia]

Definitly do the swap. You will be happy with the end results.

[totaljoint]

I thought in previous posts that it was the transfer case from the TD that would help the top end of the 712 and still give good low end torque, but that a 2.5 liter conversion was necessary first.

Would the TD transmission exchange achieve the same ends with the stock engine?

[M Wehrman]

The TD trans in my 712 likes to start in first. The jog into second takes a little practice,but is no big deal. Drawback- gearing a bit higher than stock for off-road. Pluses-fourth gear is essentially the same as fifth on a stock truck and when you shift to fifth the RPM 's drop by a 1000. This gear is unusable in uphill scenarios. On flat ground it is real sweet,MUCH better mileage and quieter (55-60). On the insane side,downhill you can hit around 78mph in a 712. After doing that,I had to replace several hub seals! I still have my old trans,if I had to shell out major bucks AND my old trans I may not be as happy. In an hour I could go back to stock,I like options. I've been running this trans a little over a year and I am still on the fence as to how happy I am with it but I still keep up with the other Pinzes.
That's enough ramblings from me.....
Mark

[David Dunn]

I had put a TD tranny into my 712 a long time ago. If it wasn’t that I sold the truck shortly afterward , I would have put the stock trans back.

As Mark said, you will need to use 1st gear sometimes in the takeoff, where you don’t with the stock trans, and only be able to use OD on the open road.
The spacing on the intermediate gears are spaced differently too. The trans in the TD could also stand to have one more intermediate gear ( a 6 speed), as the spacing is a bit much

To get a better road speed, change the transfer case to one from a 710, it’s 12% higher than the 712.

Lastly, the 716/18 transfer case will not fit into a 710/12. The input shaft is on the opposite side of the case. The stock gearing of the TD t case is also a lot lower than the 712’s to better handle the gearing of the OD tranny in the 716/18. 1.06 in high range, and 2.451 in low range, compared to 1.0 and 1.92 in the 712 (the 710 is .88 and 1.69).
This gearing in the 716’s trans and T case compliments each other for the improved highway speed and a low offroad range to match the 712 in low range.

[acebee]

On flat ground it is real sweet,MUCH better mileage and quieter (55-60). On the insane side,downhill you can hit around 78mph in a 712. After doing that,I had to replace several hub seals!
Mark

i agree ..haven't had to change hub seals as yet - but I limit downhill to ~65mph..

[pinzwheeling]

The minor loss of low end is nothing compared the the quieter and I'd imagine more fuel efficient nature of the higher gears. In SoCal, it is a huge advantage; you would be able to at least be only 15 MPH below the 80MPH speeds normally carried on the freeways.

I swapped the stock tranny to the TD tranny on my 712 right before I sold it; it's a good thing that I didn't keep it long, I may never have sold the truck!

SB flies past everyone else when he's drving the 712 - uphill, downhill and on flat ground. Granted, the 712 that SB has is a pretty strong truck, but I have to attribute most of the speed he carries to the TD tranny

[acebee]

On flat ground it is real sweet,MUCH better mileage and quieter (55-60). On the insane side,downhill you can hit around 78mph in a 712. After doing that,I had to replace several hub seals!
Mark

i agree ..haven't had to change hub seals as yet - but I limit downhill to ~65mph..

massive correction! < expletives removed >

Jim L changed the left rear most hub seal last week ..

spoke too soon earlier last month

if any body sees me faster than 95km/h from now on..

- please respond on this forum thread..

i shall give as fribee a cap & t-shirt to the witness.

[pinzwheeling]

You passed me last Tuesday going up the 15 towards Riverside while I was driving around 70MPH. Do I win?

[acebee]

While the date-time-stamp of the post applies ( I really decided the giveaway while posting the above post! - to avert my driving style )

>>>Sun Jul 11, 2010 5:12 am eastern << applies.

however there will be a surprise gift by truckhaven mogfest for the spotter-in-chief

& will need to save till then to afford it !

unless I get a speeding ticket on the 712 - then of course all bets are off !!

but I shall post the picture of the ticket duly per Jim Tucker's advice.