no speedometer in my 94 chevy exdt. cab. HELP!

[youngblood78]

Hey yall im new on this page here I have a 94 chevy ext. cab 4x4 with a manual tranny and I have no speedometer reading. every now and then it will bounce from 0 to close to the speed im doing then just falls and won't read I just got the truck today and would like to get it on the road daily driving asap ive read other places on wjat it could be vss. drac. But frankly im not tech. Savy so any imput from you guys would be greatly appreciated. Thank you.

[rustymarco]

change the speed sensor in the tail of the transfer just follow the wires, you not need to be a tech guy just take your tools and change it like a spark plug nothing go to exploit

[ChevyTech]

Speedo in-op

Here are some steps to see where the problems is.

Check and see if a trouble 24 is stored in the computer. If there is no speed signal getting to the computer it should have stored this code. Let me know if you need instruction on checking for a code.

Is the brake light on the instrument panel on?

RWAL was standard equipment starting in 1988 on full size trucks. RWAL stands for REAR WHEEL ANTILOCK. If the is no speed signal getting to the RWAL module, the RWAL system should set a trouble code and turn on the Brake light on the instrument panel.

If it has 4 wheel ABS that system will also set a code if there is a problem will the vehicle speed signal.

If there are no computer codes or anti-lock brake codes, then the problem is most likely inside the instrument panel.

If it has cruse control see if it works.

Here is a thread where it ended up being an ignition switch failure, but his vehicle had multiple problems.
http://67-72chevytrucks.com/vboard/s...d.php?t=365875

[Mr_Rich]

The speedo in my '89 intermittently drops and seems to do this more often when it's cold. I thought it was the speedo module and bought a NOS module off Ebay. I swapped it out and the problem still exists. I've determined it's an intermittent open on the gauge cluster circuit board. I'll eventually pull it out and re-solder the connections. For now I just bang on the gauge cluster with a knuckle and it starts working again. I catch the problem every time I hear the engine change tone since I don't stare constantly at the speedo.
What I wish is that there was a plug adapter to convert the 88-91 plug to the 92 and later plug so the later gauge cluster would fit the earlier trucks. I'm not ready to cut in to my wiring harness for a long time...

[ChevyTech]

Originally Posted by Mr_Rich

The speedo in my '89 intermittently drops and seems to do this more often when it's cold. I thought it was the speedo module and bought a NOS module off Ebay. I swapped it out and the problem still exists. I've determined it's an intermittent open on the gauge cluster circuit board. I'll eventually pull it out and re-solder the connections. For now I just bang on the gauge cluster with a knuckle and it starts working again. I catch the problem every time I hear the engine change tone since I don't stare constantly at the speedo.
What I wish is that there was a plug adapter to convert the 88-91 plug to the 92 and later plug so the later gauge cluster would fit the earlier trucks. I'm not ready to cut in to my wiring harness for a long time...

This style of dash board has problems with the connection at the instrument panel. When hitting the dash helps, often cleaning the the connector will help.

There are varying opinions on the best practice for resolving the connection issue.

My suggestion is to be gentle when cleaning the connections.
Don't use a wire brush or rough sand paper on the connections.
I use a liquid cleaner & lube that protects the connection from air. This product is not longer available for retail purchase as far as I know.

[youngblood78]

Omk I think I have a common problem from what yall tell me . No it has not showed any check engine lights but I took it out on the back roads tonight and yes the park break light did come on not becuz I forgot the break havmt used it lol but the speedo did work for just a few seconds and read about right but then just started going crazy would read higher with rpms of motor pop the gas revs up speedo goes up and falls...

[youngblood78]

If its any count my water temp guage works half the time but all the others are fine

[ChevyTech]

If the park brake light came on, read the trouble stored in the Anti-lock system.

Here is a thread that will help.
http://67-72chevytrucks.com/vboard/s...d.php?t=399153

[rustymarco]

ground problem maybe ,check all the grounds

[youngblood78]

May have found my problem wires to the speed sensor on the back of the case were rubed bare from the front drive shaft flange going to get a new wire plug and all tie it up hope that fixes it... but while I was under the truck thought I would fix the vibrations I think comeing from a bad u joint and ran in to a delay pulled the yoke out of the case and lost some fluid not sure what gose back in it atf? Or gear oil its a nv 4500/np241 combo

[ChevyTech]

Rubbed bare VSS wires will definitely cause the problems your truck has.

New Venture Gear 4500 (5 speed) manual– Synthetic 75W-90,API GL-4 gear lube, P/N 12345871


New Process 241, 231 and 233 - Dexron II automatic transmission fluid - Old number P/N 1051855, new number P/N 12345881

[youngblood78]

Thanks chevy tech your knowledge is awesome
I asked about the case fluid because when I pulled the yoke out it looked like gear oil real thick consistency but red color

[ChevyTech]

You're welcome!

ATF is not thick so someone could have put another product in your transfer-case, maybe to help control leakage. Or maybe it is a mix of fluids.

[youngblood78]

Mixing the tcase fluid shouldnt hurt it though right?

[ChevyTech]

Using the wrong fluid can do damage.

This is even more of a concern in the Manual 5 speed transmissions. Especially the 5LM60, HM290, HG290,NV350,Getrag