transmissions

[balcom robin s]

Yes (and so can you).
When I brought my GMC home, it ran great, with lots of power. Then I
realized that it didn't shift into third gear the entire way home. While
pondering my next move I discovered a book at our local library - "How to
Work With and Modify the Turbo Hydra-Matic 400 Transmission" by Ron
Sessions. I knew that the 425 was similar to the 400, and in the book is a
troubleshooting section. I got some fittings, hose, and pressure gauge
together, followed the steps in the book, checking pressures at various
speeds, and found that the kick-down solenoid was not working properly - got
another from a transmission shop, installed it, and presto! third gear was
back! When I dissected the old one I found that the insulation on the wires
for the solenoid had become brittle, a piece had broken off, and was stuck
in the solenoid, holding it open. My first experience with an automatic, and
I got out of it super-cheap. I doubt that I'll ever get brave enough to
tackle a rebuild, though.

> ----------
> From: LNelson208[SMTP:LNelson208]
> Reply To: gmcmotorhome
> Sent: Monday, May 10, 1999 5:34 PM
> To: gmcmotorhome
> Subject: GMC: transmissions
>
> Can a shop run a diagnostic on a tranny whilst it resides in the coach,
> you
> know, like pressure, etc. ??????? Larry in MO
>

 

[john dolan]

Larry said...
> I have been a little conerned about the coaches ability to get away
> from a red light or stopsign when on any kind of grade, even in low
> gear.

Hate to say it but that sounds like my transmission before it failed
Larry. I put a lot of miles on the coach like that, though. It ran fine
on the flat. I didn't know what a 455 and good transmission felt like in
a coach, because that's the way it came to me. After it was repaired the
difference was awesome. 1300 miles after the repair I lost first gear,
and the pickup (in S ) from a standing start going uphill was still much
better than I was used to before the repair, even in first. They called
it slipping, but the engine would bog down trying to get going from a
standing start going uphill. That's how I learned about power tuning my
distributor and that's how I got out of some steeply graded campgrounds.

Hey, have you ever driven a friend's or another GMC for comparison.
That's what I needed to do. If you haven't Larry, I urge you to do
a comparison test drive before you go to Colorado this summer.

- --
"I do whatever my Rice Krispies tell me to..." John said, from inside a
1974 Glacier.

 

[thomas g. warner]

YUP!, They can do it while they change the filter and fluid.

>Can a shop run a diagnostic on a tranny whilst it resides in the coach, you
>know, like pressure, etc. ??????? Larry in MO
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
"The beautiful Mohawk Vally"

 

[john wright]

Haven't heard anything bad about them. I called them on a replacement
last fall to check prices. Thought the pricing was ok.

J.R.

>
> GMCers
>
> Some time back I sent this link but got no replys.I still would like to know
> if any of you guys in the North West have ever heard of this company.
> The are in Portland, OR. I talked to them some time ago. They said they
> could supply transmissions for our GMCs. They have two versions.
> Regular duty and a heavy duty one which includes a TransGo shift kit
> and heavy duty TC. Regular duty was $725 and heavy duty $875. I
> think that was the price-----check to be sure. Much better prices than
> I have seen elsewhere.
>
> TRANSMISSION EXCHANGE CO List of
> Products Transmissions Transmission Parts.
>
>
> http://www.txchange.com/main.htm
>
> Take Care
> Arch 76 GB IL

 

[bruce herrin]

Just been lurking for awhile, now its time to maybe start a controversy.

Anybody have any experience with a switch pitch transmission. I know
that they generate a lot of heat,(in low range) but maybe with extra
cooling.....

I have a 3.21(think that's the right number) final drive and I don't
know if I want to turn the extra RPM's all the time for an occasional
hill.

Anyway its a fresh rebuild with a heavy duty torque converter and I
wouldn't have to use the switch.

Bruce
77 Palm Beach

 

[travis martin]

I've had a little experience with switch-pitch...used on cads and olds from
66 through 68. I haven't owned a Torpedo so can't say for sure about them,
but I know for sure that the 67 and 68 Eldorador had them, so the necessary
parts could be obtained to put one in a GMC...front pump, valve body, torque
converter, solenoid, connector etc...

But my experience with them is such that I consider it a waste of time.
Doesn't seem to make enough additional torque to justify the other
compromises. Of course, I never tried one in a 12000 pound vehicle; possibly
it would be an asset.

My gut feel on it is lotsa smoke but no fire.

Travis

- -----Original Message-----
From: Bruce Herrin
To: GMC Digest
Date: Thursday, May 20, 1999 9:59 PM
Subject: GMC: Transmissions

>Just been lurking for awhile, now its time to maybe start a controversy.
>
>Anybody have any experience with a switch pitch transmission. I know
>that they generate a lot of heat,(in low range) but maybe with extra
>cooling.....
>
>I have a 3.21(think that's the right number) final drive and I don't
>know if I want to turn the extra RPM's all the time for an occasional
>hill.
>
>Anyway its a fresh rebuild with a heavy duty torque converter and I
>wouldn't have to use the switch.
>
>Bruce
>77 Palm Beach