GMC Vandura

1990 GMC Vandura All Part Groups   

Have 1990 GMC 2500 Van. Need Differential (Rear End). What years of GMC or Chev would be interchangeable with this van.

Your best bet is to contact a local salvage yard. They have the compatibility books and can advise you. That is how they know what to offer to meet the need.

Different size engines and type/series transmissions will factor also in order to get the one that will provide a good power curve for load/pull variations.

Roger

Have already checked at the local salvage yards. They cannot help me or have any compatibility books. Live in rural area, no big yards around.

All right, I didn't know that. I'll still try to help.

What engine and transmission do you have now? Do you know the differential gear ratio currently in your van? Do you want to change the ratio? Are you going to change the entire third member or just the carrier?
Posi-traction or not?

With the answers to your questions how will the local guys near you know what part to sell you? They'll have to identify their stock part gear ratio or you could get parts you don't want.

Businesses are closed where I am. I'll try tomorrow and report any way they respond.

Roger

Thanks for the help. Will try to answer your questions in order.
350 engine
3 speed overdrive transmission
Do not know the differential gear ration,
not concerned about gas mileage
Want to change the ratio? (doesn't matter)
Going to change the entire third member
No positraction

Guess the local guys here don't know very much, never had to use them much. In my late 60's, working and used this van every day. Never any problem before.

Thanks again.

Do you find the list og Regular Production Codes (RPO Codes) on the glove box door? Look for the codes tht begin with G

G72 : AXLE REAR, 2.14 RATIO

G75 : AXLE REAR, 3.62 RATIO

G80 : AXLE POSITRACTION, LIMITED SLIP

G87 : RING GEAR, 8.50 INCH

G89 : RING GEAR, 7.50 INCH

G92 : AXLE REAR RATIO, PERFORMANCE

G9S : AXLE REAR RATIO, ECONOMY

GH0 : AXLE REAR, 3.54 RATIO

GH2 : AXLE REAR, 2.29 RATIO

GH3 : AXLE REAR, 2.77 RATIO

GH4 : AXLE REAR, 2.92 RATIO

GK9 : AXLE REAR, 4.63 RATIO

GL3 : AXLE REAR, 6.17 RATIO

GM1 : AXLE REAR, 2.59 RATIO

GM3 : AXLE REAR, 3.45 RATIO

GM8 : AXLE REAR, 2.56 RATIO

GQ1 : AXLE, STD RATIO

GS4 : AXLE REAR, 3.70 RATIO

GT4 : AXLE REAR, 3.73 RATIO

GT5 : AXLE REAR, 4.10 RATIO

GT7 : AXLE REAR, 3.33 RATIO

GT8 : AXLE REAR, 4.10 RATIO

GTY : AXLE, WIDE TRACK

GU1 : AXLE REAR, 2.41 RATIO

GU2 : AXLE REAR, 2.73 RATIO

GU4 : AXLE REAR, 3.08 RATIO

GU5 : AXLE REAR, 3.23 RATIO

GU6 : AXLE REAR, 3.42 RATIO

GV2 : AXLE REAR, 5.83 RATIO

GV4 : AXLE REAR, 3.36 RATIO

GV8 : AXLE REAR, 2.72 RATIO

GW4 : AXLE REAR, 3.31 RATIO

GW6 : AXLE REAR, 3.27 RATIO

GW9 : AXLE REAR, 2.93 RATIO

It will tell us what you have...

Roger

Many sets of Codes, only 2 start with a "G"

GU 6 and
G50

Does that help?

Okay, GU6 is a 3.42 ratio.

My guy says shop 1988 - 1995 year models.

Roger

Thank you so much for your help. This helps a lot to try and locate something. Thanks again.

Ready to close this question? Please click on OK to finish up.

Thank you!

Roger

1986 GMC Vandura Fuel System Failing When idling Always

The engine will not idle. I've replaced the spark plug wires, plugs and distributer rotor. The timing is correct. I purchased and installed a rebuild kit for the carburator and it still won't idle.

I need some more history on the vehicle. Did the problem arise suddenly or over a period of time? Have you replaced the fuel filter? If the engine starts will it run at a speed above idle (with assistance)? Let me get some more info and we can go from there. Al

The problem has just started recently. The fuel filter has been replaced. It won't continue to run unless I press and depress the accelerator repeatedly. If I hold the accelerator down it dies. If I start the engine and try and let it idle alone it dies.

Ok, we have a nice start and it sounds like u have some mechanical abilities. Is the engine fuel injected, Carb or the carb with injector(s)? If with a carb with injectors, is it a single or double injector set up. How many miles are on the engine and does it backfire thru the carb or thru the exhaust. Mid 80's engines had lots of potential set ups. Al

The engine is an V-8 305 with a rochester 4 barrel carb; not fuel injected at all.The engine has about 218,000 miles on it. I've checked the vaccum hoses for leaks and found none.

Ok this is going well. If you pour some gas down the carb and then crank the engine will the car start? If so by adding a little gas to the carb with the car running will you or can you keep the car running? Really stupid question did this problem start shortly after taking and filling the tank with gas? And have you added any fuel to the tank since this problem started. It sounds like either you have no fuel in the tank or you have water in the tank or you have a load of water in the carb bowl or you have a clogged filter in the fuel tank. We are on the right track. Al

I've never tried adding gas directly to the carb, but the engine will crank and start every time... it just won't continue to run. I know the tank has enough gas but as far as if there is water in it, I'm not sure. I'd like to think not but I could be wrong.

I forgot to add that I haven't recently filled the tank with gas and I within the past 2 days cleaned and rebuild the carb. No water was present there.

Well since you rebuilt the carb and found no water lets not assume there is any.....Try adding fuel to the carb while the engine is running and this will verify if the problem is fuel or spark related. If the engine quits running even thou your adding fuel the problem may be leading to a faulty coil, give the carb a shot of fuel while it runs and see if you can keep it running. Let me know. My responses may be a little slower for the next 2 days due to impending computer issues. I wll do my best to stay online. AL

I'm sorry it's taken me so long to get back to you. I'm in the Navy stationed overseas so my work schedule is very irratic. I did as you asked and the vehicle does idle when I pour gas into the carb.

I need some more history on the vehicle. Did the problem arise suddenly or over a period of time? Have you replaced the fuel filter? If the engine starts will it run at a speed above idle (with assistance)? Let me get some more info and we can go from there. The reason I asked if the engine will continue to run was to verify the fuel delvery system is ok. I do not believe the problem is ignition related. Let me know and I understand the needs of the Navy, I am retired ENCS. Let me know what I can do to help. AL

The problem did just recently start. I did replace the fuel filter. The only way it will idle or run is when I press the gas and release the pedal continuously. If I leave the pedal down, it will slowly slow down and die plus backfire through the carb. If I do nothing and let the engine run, it will just simply die.

The backfire is not a good thing. Normally a sign of timing problem. Have you verified the timing. There is a possiblity the engine jumped time by one tooth. There was a period of time when the engines used a fiber timing gear vice the metal ones. It is worth looking at the timing and lets leave the fuel delivery alone. bring the engine to top dead center on the crankpully and find nr 1 spark plug. remove the dist cap and see if the rotor is pointing at the nr 1 position. (it may be 180 deg off, if so, rotate the engine one more revolution) see where the timing marks point. Al

I promise the timing is correct. I verified it twice. I did have to replace the plastic ring for the fuel filter with a rubber o-ring. The reason is I found that the threads to the fuel filter b-nut was cross threaded, the only way I could keep it from leaking was to put an o-ring there and to put sealent around the threads. I'm not sure if that plays a part or not. I do have another plastic ring for it but I will still have to put sealent on the threads of the b-nut.

Ok you sound really convinced the timing is not the problem. Lets go back to the fuel delivery system. Does the Carb have a single or double injector set up or is it a real carb (and what type (Holley, Carter, etc)) Let me know. AL

It's a Rodchester quadrajet 4 barrel carb.

Float adjustment on a Quadrajet is critical. Too high the carb floods gas all over, too low and the engine is starved. Try to add some gas to the eng thru the carb while someone starts it. If it runs better than the problem is most likely in the carb and most likely with the float adj or a seal that is leaking in the carb. Let me know how that works out. Al

I did as you asked and the engine does run when you pour gas directly into the carb. When I got the rebuild kit it said to set the float 3/16" from the float foot to the top or bottom as you will of the housing. I thought that was set as close as can be but then I could be wrong.

Well that confirms the carb as the problem. So we have a few directions to go.. purchase a new carb (not recommended), purchase a good used carb (not recommended but a cheaper option), rebuild the carb again (a good option) or have someone else rebuild the carb another option. You said you are overseas.. what country are you located in and are there any Engineman or Machinist Mates or AD personnel at your command? They would would be a great source of support. Let me know if this helps. AL

Have not heard from you in a while so I thought that I would check on the status of your GMC. Things gotten any better??? Let me know.. have a great day. Al