Help, 1987 shortie cruise, convertor, and speedo ?'s - The 1947 - Present Chevrolet & GMC Truck Message Board Network

nico · 09-09-2008, 04:27 PM

I recently bought a 1987 short wide fi350 700r4 and have been trying to diagnose a few problems with it. First is the speedometer, it reads about 20-25 mph slow. I can be humming along passing people on the interstate (normally around 75) and the truck shows 52-55. Second is the lockup convertor not working? And third is the cruise doesn't work, I have replaced the rotten vacuum lines and tried to adjust the slide linkage to no avail. Any help would be appreciated, and i will post up some pics soon. Thanks Kaysen

**Captkaos** · 09-09-2008, 06:24 PM

What size tire/ wheels are on the truck?
How is the cruise not working? As in it locks the speed the stops?
Are you asking or telling that the lockup doesn't work? This is controlled by the ECM.

87Bob · 09-09-2008, 06:30 PM

Sounds like the speedo may have the wrong plastic gear in the tail of the transmission. Drive a measured distance 5 miles or so and see if your odometer reads right. If it does that's not it if doesn't then you need to get the correct one.

Chevrolet4x4s · 09-09-2008, 06:41 PM

1987 should have electric speedometer if 2 wheel drive, has the gear ratio been changed possibly?

Shane

nico · 09-10-2008, 05:40 PM

I am running 275-60-15s on the rear right now. The lockup convertor isn't working, at cruising speed in OD tap the brake pedal and it doesn't have a change in rpm? I have been told this is how to check to see if the convertor is working.. If I am wrong please let me know as I am not 100% sure. And for the cruise, its just dead. Say im running 75 (showing 55, lol) hit the cruise button and let off the gas, nothing engages and I start to slow down.
Gear swap is a possibility, will look into that as soon as it quits raining.

09-09-2008, 04:27 PM	#1
nico Registered User Join Date: Nov 2006 Location: Marietta, OK Posts: 153	Help, 1987 shortie cruise, convertor, and speedo ?'s I recently bought a 1987 short wide fi350 700r4 and have been trying to diagnose a few problems with it. First is the speedometer, it reads about 20-25 mph slow. I can be humming along passing people on the interstate (normally around 75) and the truck shows 52-55. Second is the lockup convertor not working? And third is the cruise doesn't work, I have replaced the rotten vacuum lines and tried to adjust the slide linkage to no avail. Any help would be appreciated, and i will post up some pics soon. Thanks Kaysen

09-09-2008, 06:24 PM	#2
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: Help, 1987 shortie cruise, convertor, and speedo ?'s What size tire/ wheels are on the truck? How is the cruise not working? As in it locks the speed the stops? Are you asking or telling that the lockup doesn't work? This is controlled by the ECM. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

09-09-2008, 06:30 PM	#3
87Bob Registered User Join Date: Nov 2007 Location: Franklin Indiana Posts: 635	Re: Help, 1987 shortie cruise, convertor, and speedo ?'s Sounds like the speedo may have the wrong plastic gear in the tail of the transmission. Drive a measured distance 5 miles or so and see if your odometer reads right. If it does that's not it if doesn't then you need to get the correct one. __________________ My Truck's not leaking its marking its territory!

09-09-2008, 06:41 PM	#4
Chevrolet4x4s Registered User Join Date: Nov 2005 Location: WV Posts: 227	Re: Help, 1987 shortie cruise, convertor, and speedo ?'s 1987 should have electric speedometer if 2 wheel drive, has the gear ratio been changed possibly? Shane __________________ 1993 K1500 350 5 speed 1985 K10 Silverado Vortec 406 5 speed (in body shop) "I been drivin' this '85 pickup truck Them buddies of mine call it a bucket of rust She's a little beat up but she still runs like the wind Yeah, kinda like me I been banged and bruisedBeen around the block a time or two But I'm runnin' like new goin' places I never been No, I ain't broke I'm just broken in" 1963 Dodge Townwagon(its amazng what 30 years and zero miles will do to a vehicle ) Member#20327

09-10-2008, 05:40 PM	#5
nico Registered User Join Date: Nov 2006 Location: Marietta, OK Posts: 153	Re: Help, 1987 shortie cruise, convertor, and speedo ?'s I am running 275-60-15s on the rear right now. The lockup convertor isn't working, at cruising speed in OD tap the brake pedal and it doesn't have a change in rpm? I have been told this is how to check to see if the convertor is working.. If I am wrong please let me know as I am not 100% sure. And for the cruise, its just dead. Say im running 75 (showing 55, lol) hit the cruise button and let off the gas, nothing engages and I start to slow down. Gear swap is a possibility, will look into that as soon as it quits raining.



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