trans upgrade

[Deano56]

it looks like we are going to have to wait to upgrade to a newer MH so I would like to upgrade the Turbo Hydramatic 400 to the 700R trans. Has anyone done this here? Seems at 65 mph its topped out, so with the final drive ratio at .70 I think that would be helpful

[Pauljdav]

I would look at the gear vender OD option. As others have said it will not be cheap and you will never get your money back from any increase in mileage. If there even is any.

Paul

[FuzzyKnight]

Put a GearVendors on it!!

[ferndaleflyer]

Since they are using T-400s in drag cars of around 1800 horse power that go 3.80 seconds in the 1/8 mile why would you change from the strongest trans out there? + none of the things you mention will be cheap or easy. Just my $.02

[Deano56]

Deano56 wrote:

ScottG wrote:
That would be a big job. Mounts would have to be created and something would have to activate the locking torque converter in the 4 speed that you don't have now.
Have you considered getting an overdrive unit like Gear Vendors sells? They would probably have a kit to just bolt it in after shortening the drive shaft.
My FIL had one and it worked automatically just like the forth gear in an auto.

does the overdrive unit have a automatic controller?

I was searching last night and came across the 700R, it was 1200 dollars and was built to handle 650 lb of torque plus the gear ratios were better I think for moving my rig. How hard is it to do the controller for the lock up? I'm fairly good at doing these thing but not getting any younger for sure and I do have friends that would help with the fabrication if needed.

[Deano56]

ScottG wrote:
That would be a big job. Mounts would have to be created and something would have to activate the locking torque converter in the 4 speed that you don't have now.
Have you considered getting an overdrive unit like Gear Vendors sells? They would probably have a kit to just bolt it in after shortening the drive shaft.
My FIL had one and it worked automatically just like the forth gear in an auto.

does the overdrive unit have a automatic controller?

[JimM68]

I've not done it toa motorhome, but have in several GM cars.

The 4L60 is another good choice, it is a newer version of the 700r4.
Your could even go with an electronic trans, combined with an aftermarket shift control computer.
Then use a 4L60e, or a super heavy duty 4L80e.

The 80 would take anything a motorhome could throw at it stock. the 60's and 700r4 should be rebuilt and beefed up to handle the weight.

All will need some sort of controller (or just a switch) to handle torque converter lockup.

If your motorhome does not have a good sized separate trans cooler, I'd recommend adding one.

Mechanically, everything will bolt together and fit. Your crossmember will work, you might have to move it back a little.
You will have to shorten the front section of the driveshaft.

If you're not a gearhead type, do some searching at summitracing.com they will have anything you need to get this done.

[ScottG]

That would be a big job. Mounts would have to be created and something would have to activate the locking torque converter in the 4 speed that you don't have now.
Have you considered getting an overdrive unit like Gear Vendors sells? They would probably have a kit to just bolt it in after shortening the drive shaft.
My FIL had one and it worked automatically just like the forth gear in an auto.