From experience with 3 motorhomes, 2 van conversions, & 3 other tow vehicles with associated trailers, IMHO, the cheapest insurance you can buy is a good aftermarket tranny cooler, with associated temp. gauge. (your Barth probably already has the latter).

If nothing else, it will pay for itself in pucker factor reduction the first time you decide to hook up a toad, or go over the mountains instead of staying on the flat, or like Bill H., you have to back and fill in order to park or turn around on a hot summer day. Unless you never venture off the Interstate, some day one or the other will happen.

I've blown a properly-maintained tranny in a MH without an auxuliary cooler, but never in a rig with one. Once, in a MH already aux. equipped, I found temps. too high when I added a toad, and bought a second cooler with its own thermostatic fan. It didn't take much of a hill for that fan to start howling, but the trans. never got too hot.

I bought one MH transmission by trusting the factory equipment even though I wasn't towing. I don't plan to buy another one, at least for that reason.

Amen...I don't intend to tow for a while (if at all), but a transmission temp gauge is sitting on the workbench. I'm not sure where to mount a cooler on the pusher (it may already have one) but the radiator seems to be very effective.

quote:

Originally posted by Rusty:
I'm not sure where to mount a cooler on the pusher (it may already have one) but the radiator seems to be very effective.

A fan makes a cooler good in almost any position, even with no forward motion.

Based on all the sage advice from this site and locally, I've committed to swapping out the 4.56 rear end for a 4.10. In theory, I should end up with about 50-75% of GearVendor benefits at about 15-20% of the cost. The job is scheduled for later this month, after a trip from DC to the UP of MI & back, starting next week (..... to chase the elusive smelt....)

One other factor exists, and once again I'd appreciate feed back.......

In the three years I've had my unit, I've always thought the TH400 shifted a little early. I'm into 2nd gear at about 6-8mph and into 3rd at about 15-18mph. At 24' and lightly loaded, it's never been a big factor, as I've had the torque to lug my way out....The 4.10 rear will obviously compromise this somewhat and it may become a performance issue......

QUESTION: Is adjusting the shift rpm/mph points a simple external linkage issue that can be handled by Joe-the-apprentice at the local AAMCO, a quick-shift, ball-n-spring kit installation, or am I looking at some extensive internal mods?

Thanks!

quote:

Originally posted by Lee:

In the three years I've had my unit, I've always thought the TH400 shifted a little early. I'm into 2nd gear at about 6-8mph and into 3rd at about 15-18mph. At 24' and lightly loaded, it's never been a big factor, as I've had the torque to lug my way out....The 4.10 rear will obviously compromise this somewhat and it may become a performance issue......

QUESTION: Is adjusting the shift rpm/mph points a simple external linkage issue that can be handled by Joe-the-apprentice at the local AAMCO, a quick-shift, ball-n-spring kit installation, or am I looking at some extensive internal mods?

Thanks!

Have you had the vacuum modulator checked? Short shifting can be caused by modulator problems, but there is usually hard shifting along with that. However, it is easier to observe hard shifting in a car than a motor home. A new modulator and vacuum hose connections could effect an improvement. You probably need new rubber lines, anyway.

Before modifying the governor, I would suggest you drive it with the new diff gears and observe the tach. Then get back to us on that. Early shifting with a light throttle on level ground can be a gas saving feature. You can also shift manually in the mountains.

When you are ready, it is a pretty simple matter of changing governor weights and springs. The governor is under a sheet metal cover on the side and is easily accessed. Inspect the nylon drive gear while it is open.

http://store.summitracing.com/egnsearch.asp?N=115+400004+300191&autoview=sku

http://www.tciauto.com/instructions/326500_inst.htm

quote:

Originally posted by Lee:
I've committed to swapping out the 4.56 rear end for a 4.10. In the three years I've had my unit, I've always thought the TH400 shifted a little early. I'm into 2nd gear at about 6-8mph and into 3rd at about 15-18mph.

So..............still waiting with bated breath ...............how did the ring and pinion replacement work out?

Any news on the short shifting?

If it were me I would look arround for a later model used 4 speed transmission with o/d. Not only do you slow down your engine you get a lockup torque converter. To me this is a real win/win.

quote:

Originally posted by Gary Carter:
If it were me I would look arround for a later model used 4 speed transmission with o/d. Not only do you slow down your engine you get a lockup torque converter. To me this is a real win/win.

You're missing the OP's (original poster) original intent. He stated...

quote:

Originally posted by Lee:
Due to unit's age & modest investment, GearVendors is not an option. But how about the rear end?.......It's currently a 4.56

Ring & pinion swap-outs have been quoted in the $400-500 range, so cost is much less of an issue than a GV overdrive project.

I don't want to reinvent the wheel, but it sure would be nice to quiet-down the doghouse a little - maybe even bump-up the mpg a tad.....without too much compromise of power.

He was looking for a low cost way to bump up his mileage - slow down the motor and save some money over the cost of a "Gear Vendor" unit. Even if he got the transmission for free, he would still need to install it and rework the drive shaft - this is hardly what the OP had in mind when he first posted it.

I will agree, if it was me, I would be looking for an overdrive transmission with a lockup converter. And based on the above numbers (2' shorter = a 350 cid) maybe even doing the rear end too.

quote:

Originally posted by Bill h:
So..............still waiting with bated breath ...............how did the ring and pinion replacement work out?

Any news on the short shifting?

Yeah, what happened to keeping us posted?

When I did my tranny back in 2000, I considered a 4L80D. Both the overdrive and lockup converter appealed to me. The 4L80E needs a little work to stand up to being in the middle between a hi torque 502 and 10 tons up a mountain, and, at that time, there was no stand alone computer for putting one in an older vehicle.

Also, I have rebuilt TH400s with no special tools save threaded rod and shim stock. Never done a 4L80E. A modified 4L80E would be even more of a problem to get properly fixed if broke down on the road, too.

So, it didn't happen.

But, I sure could use a locking converter. The 502 makes a whole lot more uphill heat in the converter than I or anyone else predicted. My cardiologist has insisted that I remove that particular temp sensor.

Does anyone know of a way to make a locking converter work with a TH400. Heck, Packard did it in the late 40s or early 50s with the Ultramatic. Even manual control would be fine.E