Turbo 400 / 4L80E

[bkahler]

Originally Posted by LimeyRich

Well Brad I still don't think we have seen an electric/hydraulic E brake! They have a whole lot of "unnecessary plumbing" and cabling in order to make the parking brake "secure" and "safe" for us feeble RVers!.

I wonder if GM developed the smaller brake drum for vehicles where having a 14" (or there abouts) diameter brake drum under the floor would take up to much space.

It is possible that your 4L80 has a traditional pull-on parking brake as it appears that some earlier models did not yet have the "Auto-Park" system. Unfortunately I do not have proof of this, only what I have tried to glean from other posters on forums.
It also appears that the drivers of midsize commercial trucks were deemed to be trusted to be able to put on a handbrake.

I'm going to have to pull my 4L80E out of the corner after I get home to see just what it might have. I really need to find any identifying numbers on it so I know just what I have.

The parking pawl is good news though. Your 4l80 probably has it, if not. All the small parts for adding "Park" are readily available new or used, and most 4l80's come with them. They are easily installed by any transmission shop or mechanic who dabbles in transmissions.
See the second pic in Jakes 4L80 build sequence on the "Nasty Z28" forum. The rod that runs from the shift lever to the back of the transmission activates the small spring loaded "pawl" parts located in the back of the case, here:
> 4L80E Build - NastyZ28.com <

I'll take a peak.

Thanks!

Brad

[LimeyRich]

.......new trans support is here, sadly it is identical in shape and dimensions to original 1988 support. OK , done for now, just do not feel like fighting it today.
All the best.

[bkahler]

Originally Posted by LimeyRich

.......new trans support is here, sadly it is identical in shape and dimensions to original 1988 support. OK , done for now, just do not feel like fighting it today.
All the best.

Bummer. Now you're making me wish I had been able to keep the cross member from the box truck where I got my transmission. Hang in there Rich.

I think over the Thanksgiving holidays I better head out in search of some salvage yards to see if I can find something that is appropriate.

Brad

[choctawmel]

You may want to look at my trails blood and tears when I did the 4L80e. Allison questions / how many cans of worms can a 28' motorhome hold and 4L80e what have I done!
I started out with a 'heavy duty' tail shaft housing but could not find an e-brake to fix. When I went to one junk yard the guy said, "If you find one, I need one too." The HD housing was only used on the tilt bed wreckers. So, I found a 'medium duty' housing and the first junk yard I visited had a '70?? motor home with a 400 trany. I got the e-brake and cross member. Had to drill new hole in the frame (not fun) for the cross member and mover the tail shaft mount ( more drilling) to clear the e-brake drum, but all worked in the end.

[LimeyRich]

[ Hang in there Rich.]
[You may want to look at my trails blood and tears when I did the 4L80e]

Brad and Mel, Thanks for posting! I have looked and looked through the threads for the Airstream 4L80 info, And have not found it.
I know it was there because I read through it all in 2009/10. Can you point the way back to those threads?
yeah, it really is a big job to tackle, but I can see it going together now.
Because of my previous health problems, I know to push the "envelope" but not exceed my physical capabilities. I just spent too much time under the 345 this week and both frustrated,and exhausted myself to the point that a small snag was temporarily overwhelming.
Plus I have faithfully subscribed to the following uplifting philosophy: " When in danger,when in doubt. Run in circles, scream and shout!"
All the best. Thanks. Rich.

[Keyair]

Is this the one Choc was refering to?
http://www.airforums.com/forums/f159...old-69221.html

[Keyair]

Rich...
If you had not seen this already, some great info here...

Automatic Overdrive Transmission Swap

[bkahler]

Originally Posted by choctawmel

You may want to look at my trails blood and tears when I did the 4L80e. Allison questions / how many cans of worms can a 28' motorhome hold and 4L80e what have I done!
I started out with a 'heavy duty' tail shaft housing but could not find an e-brake to fix. When I went to one junk yard the guy said, "If you find one, I need one too." The HD housing was only used on the tilt bed wreckers. So, I found a 'medium duty' housing and the first junk yard I visited had a '70?? motor home with a 400 trany. I got the e-brake and cross member. Had to drill new hole in the frame (not fun) for the cross member and mover the tail shaft mount ( more drilling) to clear the e-brake drum, but all worked in the end.

I just finished reading your thread on installing the 4L80E in your 345. Quite and ordeal! Now that it is a couple of years down the road are you happy with the conversion?

I was going to ask you what you did for a replacement cross member then I realized that you had removed an Allison transmission so the cross member would have been different. Rich and myself are switching from TH400/475 transmissions to the 4L80E and Rich is having trouble sourcing the correct cross member.

The 4L80E that I will be using came from a 92 Chevy box truck so it has the parking brake on the back. Only problem is my 74 Argosy motorhome has the parking brakes in the rear brake drums

So I have to decide if I want to use the original brakes on the differential which would mean replacing the tail shaft housing on the transmission or use the the drum brake on the transmission which means figuring out the cabling issue and abandoning the original parking brakes at the differential.

I probably won't worry about this to much until I get farther down the road.

Brad

[Smartstream]

Brad if you choose to stay with the rear axle parking brake I don't see a need to change the tailshaft housing. Just remove the backing plate and the drum and bolt the flange up to the drive shaft.

On another point if I had a choice I would keep the axle brake. I have leveling jacks and if you get one side up too far and loose traction on one rear wheel, with a drive line brake you loose your parking brake. With the axle brake you still have one wheel holding. Large modern parks are not a problem but in some of the more interesting parks the pads are not so level and in the rain and mud it can get interesting.

Good luck, Dan

[LimeyRich]

Brad , you have rear drum brakes with factory rear emergency brakes!!
Keep that system alive, in good repair,and adjusted. That system is dead simple, anyone can work on it.
What Smartstream says too.
The reason for the transmission mounted brake in the first place, is 4 wheel disc brakes that cannot be cable actuated.
There is no reason for you to mess with transmission mounted emergency brakes.
I would just pull the small parts,(springs,shoes and cable) from the trans brake,leave the drum in place, hook up your driveshaft and roll with it.
Or if you really want to have two emergency brakes, and experience the exquisite frustration of figuring this.... out, I appreciate the solidarity of that, but really there is no need.
All the best. Rich

[Keyair]

Heres hoping they have a half price engine and transmission day sometime locally, at my favorite Junkyard...
Couple of years back I snagged a 5 speed manual trans and everything I needed for a stick conversion on my Mercedes Diesel for under $100...

Last time I was there, they had a bunch of Airport style buses... Now I will take more notice of what Chassis/Engine/Trans!

Found this exploded diagram and parts list/cost for the 4L80 transmission mounted parking brake... might help..

P3 PARKING BRAKE SYSTEM/PROP SHAFT;. Fits: P30 VAN | Nalley Buick GMC Brunswick

[bkahler]

Originally Posted by Smartstream

Brad if you choose to stay with the rear axle parking brake I don't see a need to change the tailshaft housing. Just remove the backing plate and the drum and bolt the flange up to the drive shaft.

On another point if I had a choice I would keep the axle brake. I have leveling jacks and if you get one side up too far and loose traction on one rear wheel, with a drive line brake you loose your parking brake. With the axle brake you still have one wheel holding. Large modern parks are not a problem but in some of the more interesting parks the pads are not so level and in the rain and mud it can get interesting.

Dan you have a real good point about the parking pads in parks. I've been trying to forget about the time I lowered the rear levelers on our 310 enough and ended up lifting the rear wheels off the ground and we were on just enough of an incline that the motorhome rolled backwards and hit the curb. If the curb hadn't been there we'd have been in the woods And no, I didn't have the parking brake set Needless to say that was somewhat embarrassing

Both you and Rich bring up good points about sticking with the axle e-brake so I think that is the route I'll go. I can save the e-brake off of the 4L80E for the 310 as spare parts, I'm guessing they are the same parts.

Thanks for the advice!

Brad

[bkahler]

[QUOTE=Keyair;1220201]Last time I was there, they had a bunch of Airport style buses... Now I will take more notice of what Chassis/Engine/Trans!

Whenever I'm in a junk yard I always check out any of the bigger trucks that I see. Sometimes you find an odd ball part that might come in handy.

Found this exploded diagram and parts list/cost for the 4L80 transmission mounted parking brake... might help..

By not using the 4L80E drum parking brake I don't have to do anything to have brakes. I'm all for the easy way out

[choctawmel]

Originally Posted by LimeyRich

[ Hang in there Rich.]
[You may want to look at my trails blood and tears when I did the 4L80e]

Brad and Mel, Thanks for posting! I have looked and looked through the threads for the Airstream 4L80 info, And have not found it.
I know it was there because I read through it all in 2009/10. Can you point the way back to those threads?
Rich.

Copied and pasted to 'search'. This is the treads: <http://www.airforums.com/forums/f159/allison-questions-how-many-cans-of-worms-can-a-28-motorhome-hold-69221.html> and <http://www.airforums.com/forums/f159/4l80e-what-have-i-done-75774.html>

[choctawmel]

Originally Posted by bkahler

So I have to decide if I want to use the original brakes on the differential which would mean replacing the tail shaft housing on the transmission or use the the drum brake on the transmission which means figuring out the cabling issue and abandoning the original parking brakes at the differential.

I probably won't worry about this to much until I get farther down the road.

Brad

Don't need to replace the tail shaft housing, just take the e-brake assembly off and go for it. Your may have frame holes that line up that way. With the e-brake on I had to move the cross-member forward to clear the back plate of the e-brake.

[Now that it is a couple of years down the road are you happy with the conversion?]
Yes, very happy. Less engine noise, RPM of 22-2600 (was 32-3600) going down the highway, less engine heat, gas mileage sadly about the same. May of gotten the same results by rebuilding the 545 Allison and changing the rear end gears but the cost would be about the same

[Smartstream]

I'm not real familiar with the 4L80E set up but when Airstream installed the Isuzu's they moved the transmission back a few inches, in-line six vs. V8. All they did was fabricate a Z shaped bracket to move the trans mount back. No real changes to the crossmember. I think you guys may be creating a problem unnecessarily.

Cheers, Dan

[bkahler]

Originally Posted by Smartstream

I'm not real familiar with the 4L80E set up but when Airstream installed the Isuzu's they moved the transmission back a few inches, in-line six vs. V8. All they did was fabricate a Z shaped bracket to move the trans mount back. No real changes to the crossmember.

That sure would be a nice find if it works out that way. I'll be replacing a TH400 with the 4L80E and I do know that the overall length of the 4L80E is about 3+ inches more than the TH400. If I can get by just sliding the cross member back a little bit I'd be one happy camper.

I think you guys may be creating a problem unnecessarily.

Cheers, Dan

I'll guarantee you it wouldn't be the first time that I create more problems than I solve while working on something

[Smartstream]

Originally Posted by bkahler

I'll guarantee you it wouldn't be the first time that I create more problems than I solve while working on something

Come on now, you weren't creating problems, it was all part of your self -education program. In these days of political nonsense, there is a spin for everything.

Cheers, Dan

[LimeyRich]

Great links guys. Thank you very much!
I will re-study them over the weekend.
Getting ready today for a possible brush by Hurricane Sandy, so no motorhome work till next week.

Ok, now I have a Buddhist friend, and a pal from Afghanistan, and they are both in agreement, and telling me that mechanical problems with our Airstreams are internal.
That (for me) it is all a matter of my perception of the problem, and that my attitude towards reality is much too western. Sigh...
So this weekend while Sandy goes by, I will try to meditate upon the meaning of Airstreaming, and project my karma for the next three days towards the enlightenment and fullfilment of my transmission swap..... They say everything will be alright in my driveway by Tuesday !
They are so smart, and helpful.

[bkahler]

Originally Posted by Smartstream

Come on now, you weren't creating problems, it was all part of your self -education program. In these days of political nonsense, there is a spin for everything.

Cheers, Dan

The real problem with my "self" education program is the teacher that is involved

Brad