Classic Winnebagos & Vintage RVs

Topic Boards => Info Articles => Topic started by: cncsparky on June 11, 2014, 10:22 PM

Title: TH400 transmission Kickdown switch adjustment
Post by: cncsparky on June 11, 2014, 10:22 PM
The kickdown switch mounted on my gas pedal was not working.  Found an adjustment procedure and it now makes much sooner (was not making at all).  Will re-install the switch and see if this works.   :)clap

http://forums.500cid.com/showpost.php?s=11f36db5de414ee4391437317796fdd8&p=13416&postcount=5 (http://forums.500cid.com/showpost.php?s=11f36db5de414ee4391437317796fdd8&p=13416&postcount=5)
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: Stripe on June 11, 2014, 11:06 PM
Tom where is this switch usually located on an RV, or at least on yours..?
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: cncsparky on June 12, 2014, 07:33 AM
Attached directly to the pedal assý.  Looks like they used a common GM kickdown switch, but have been unable to find a replacement at a local parts store.  Reproductions are available from auto restoration places on the web. Not sure if GM still has these available.  Can't find a part number.   
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: Stripe on June 12, 2014, 01:45 PM
Here are a few...

http://www.americanclassic.com/Google_Base_HTML_Pages/EL870NOS-1972.htm (http://www.americanclassic.com/Google_Base_HTML_Pages/EL870NOS-1972.htm)
Looks OEM..

Ugh, this one = plastic, but...
http://www.ebay.com/itm/1969-1977-Turbo-400-T-400-THM400-SUPER-TURBINE-400-KICKDOWN-SWITCH-1242101-/161023285833?pt=Vintage_Car_Truck_Parts_Accessories&hash=item257dbc5a49 (http://www.ebay.com/itm/1969-1977-Turbo-400-T-400-THM400-SUPER-TURBINE-400-KICKDOWN-SWITCH-1242101-/161023285833?pt=Vintage_Car_Truck_Parts_Accessories&hash=item257dbc5a49)

Then this one has a number on the box..
http://www.ebay.com/itm/1971-72-Pontiac-Firebird-Turbo-400-Kickdown-Switch-GM-Part-3986863-/200931819424?pt=Vintage_Car_Truck_Parts_Accessories&hash=item2ec8783fa0 (http://www.ebay.com/itm/1971-72-Pontiac-Firebird-Turbo-400-Kickdown-Switch-GM-Part-3986863-/200931819424?pt=Vintage_Car_Truck_Parts_Accessories&hash=item2ec8783fa0)
Not sure if that is OEM number or put there by local shop.

Now this one seems to have the factory number stamped on..
http://www.ebay.com/itm/NOS-GM-Chevy-Buick-Olds-Pontiac-Corvette-Automatic-Kickdown-Switch-GM-1242101-/251243680982?pt=Vintage_Car_Truck_Parts_Accessories&hash=item3a7f4a54d6 (http://www.ebay.com/itm/NOS-GM-Chevy-Buick-Olds-Pontiac-Corvette-Automatic-Kickdown-Switch-GM-1242101-/251243680982?pt=Vintage_Car_Truck_Parts_Accessories&hash=item3a7f4a54d6)

Big differences in prices..
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: cncsparky on June 12, 2014, 02:17 PM
Good work Fredric!  Looks like GM 1242101 is the original, no longer available from GM.  Haven't found a cross number yet. 
Title: Re: TH400 Kickdown switch adjustment
Post by: DaveVA78Chieftain on June 12, 2014, 09:22 PM
http://www.oldsobsolete.com/products-page/1967-pontiac-parts-for-sale/1967-1989-gm-transmi1967-1989-gm-transmission-downshift-control-switch-nos-1242101ssion-downshift-control-switch-nos-1242101/ (http://www.oldsobsolete.com/products-page/1967-pontiac-parts-for-sale/1967-1989-gm-transmi1967-1989-gm-transmission-downshift-control-switch-nos-1242101ssion-downshift-control-switch-nos-1242101/)

Dave
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: cncsparky on June 13, 2014, 12:24 AM
Wow, they want crazy money for those!  I took mine off to adjust, but didn't need to.  Push the slider assý of the switch as far down as it will go past its momentary stop as shown.  Then pump the gas pedal to its max.  After I did this, the switch is now making.  But, its not making very consistent according to my VOM(still making but the ohms reading is jumping around like a dirty connection).  Testing it out this weekend, may pull out the switch and clean it up according to the site I posted if it doesn't respond like it should. 
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: cncsparky on June 13, 2014, 12:28 AM
Thinking if I had to replace one of these gold plated switches, I would at least try to fab up a switch bracket for the carb.  Lots of options, including some aftermarket kits available.  A nitrous switch would work to since it works at wide open throttle also.
Title: Re: TH400 transmission Kickdown switch adjustment
Post by: cncsparky on September 26, 2014, 09:58 PM
Looks like someone is making an aftermarket switch now.  Seems lots cheaper. 

http://www.ebay.com/itm/1969-1977-Turbo-400-T-400-THM400-SUPER-TURBINE-400-KICKDOWN-SWITCH-1242101-/161023285833?pt=Vintage_Car_Truck_Parts_Accessories&hash=item257dbc5a49&vxp=mtr (http://www.ebay.com/itm/1969-1977-Turbo-400-T-400-THM400-SUPER-TURBINE-400-KICKDOWN-SWITCH-1242101-/161023285833?pt=Vintage_Car_Truck_Parts_Accessories&hash=item257dbc5a49&vxp=mtr)