700R4 Lockup help! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1985K10 · 11-22-2003, 10:01 PM

The TCC in my 700R4 usually locks in 2nd gear, now its only locking in OD. Where could my problem be?
Thanks in advance!

79BIG10 · 11-23-2003, 09:52 AM

I didn't think that they were supposed to lock in 2nd? I was thinking that they only locked up in OD. You might have a bad switch.

1985K10 · 11-23-2003, 10:17 AM

What switch might be bad? I replaced the one on the brakes about 2 months ago. When its locked in OD I can hit the brakes and the tranny unlocks. There must be some other switch or something along the line that controls lockup. Isnt there a vac. controlled thing on the firewall?

Jonboy · 11-23-2003, 09:11 PM

it is only supposed to lock up in 3rd and 4th gears, at speeds above 45 MPH. is your speedo cable OK?

1985K10 · 11-24-2003, 12:01 AM

I am positive it locks in 2nd and 3rd...when i drive i feel a shift from 1st-2nd, then between 25-30MPH I feel another "shift"(the TCC locking up) then at about 30-35 it shifts again into 3rd.

I read on a few sites that you can wire the 700R4 TCC to lock in either 2-3-4, or only 4th. Ive noticed a big drop in gas mileage since it hasnt been locking in 2nd and 3rd. Also, my fluid is turning brownish and smells burnt, so I'm looking into another tranny.

11-22-2003, 10:01 PM	#1
1985K10 Registered User Join Date: Oct 2003 Location: CT Posts: 315	700R4 Lockup help! The TCC in my 700R4 usually locks in 2nd gear, now its only locking in OD. Where could my problem be? Thanks in advance! __________________ Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~

11-23-2003, 09:52 AM	#2
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,774	I didn't think that they were supposed to lock in 2nd? I was thinking that they only locked up in OD. You might have a bad switch. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

11-23-2003, 10:17 AM	#3
1985K10 Registered User Join Date: Oct 2003 Location: CT Posts: 315	What switch might be bad? I replaced the one on the brakes about 2 months ago. When its locked in OD I can hit the brakes and the tranny unlocks. There must be some other switch or something along the line that controls lockup. Isnt there a vac. controlled thing on the firewall? __________________ Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~

11-23-2003, 09:11 PM	#4
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	it is only supposed to lock up in 3rd and 4th gears, at speeds above 45 MPH. is your speedo cable OK? __________________ 1974 Jimmy- 5.3/4L80e/NP241

11-24-2003, 12:01 AM	#5
1985K10 Registered User Join Date: Oct 2003 Location: CT Posts: 315	I am positive it locks in 2nd and 3rd...when i drive i feel a shift from 1st-2nd, then between 25-30MPH I feel another "shift"(the TCC locking up) then at about 30-35 it shifts again into 3rd. I read on a few sites that you can wire the 700R4 TCC to lock in either 2-3-4, or only 4th. Ive noticed a big drop in gas mileage since it hasnt been locking in 2nd and 3rd. Also, my fluid is turning brownish and smells burnt, so I'm looking into another tranny. __________________ Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~

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