dbrannon79
I'm getting there!
Hey guys, I have been reading up on the different steering gears and how the reman units have become a gamble on what you get in the box. I found a site online that shows the differences on some of the GM boxes, showing casting numbers and bore sizes. Below, each spoiler drop down will show some info in identifying these gear boxes. (I didn't post a link to the site because they sell these units and wasn't sure if it was allowed to post the link)
I am still looking for identification on some Delphi gear boxes due to the fact that the old box I have that I am considering to rebuild for my truck has a Delphi casting number on it which I have not been able to id yet, might be a unicorn lol
SAGINAW 800/808 GEARBOXES
This is the most common GM steering gearbox found in cars and small trucks from the 1960’s into the 2000’s.
The difference between the Saginaw 800 and the Saginaw 808 is the size of the piston. The 800 has a 70mm piston and the 808 has an 80mm piston. This is easy to measure from the outside of the gearbox. If you measure the end cap, the 800 is roughly 3” and the 808 is just under 3.5”.
It came in both a 3-hole “L” and 4-hole “H” mounting pattern. The 3-hole is the same pattern, just missing one hole and will fit directly into any vehicle that had a 4-hole pattern. They are much more common and easier to find cores, so we typically sell the 3-hole version. If you must have a 4-hole pattern it can be special ordered.
Pre-1980 gearboxes will have 5/8 and 11/16” SAE inverted flare fittings while gearboxes after 1980 will have 16mm and 18mm O-ring fittings. Again, the older SAE gearboxes are very hard to find, so the majority of the gearboxes we sell are metric. If you are installing into a pre-1980 vehicle that has inverted flare fittings, we can install a seat kit that will allow you to thread your existing hoses. Yes, the SAE thread pitch will thread into the metric threads!
Along with the change of fitting style in 1980, the input shaft also changed from 13/16-36 (pre-1980) to 3/4-30 after 1980. You can simply change the rag joint to accommodate a smaller input shaft. When counting the splines, it is important to know that the 30 and 36 counts include any missing splines that are removed where a flat on the shaft is.
This is the most common GM steering gearbox found in cars and small trucks from the 1960’s into the 2000’s.
The difference between the Saginaw 800 and the Saginaw 808 is the size of the piston. The 800 has a 70mm piston and the 808 has an 80mm piston. This is easy to measure from the outside of the gearbox. If you measure the end cap, the 800 is roughly 3” and the 808 is just under 3.5”.
It came in both a 3-hole “L” and 4-hole “H” mounting pattern. The 3-hole is the same pattern, just missing one hole and will fit directly into any vehicle that had a 4-hole pattern. They are much more common and easier to find cores, so we typically sell the 3-hole version. If you must have a 4-hole pattern it can be special ordered.
Pre-1980 gearboxes will have 5/8 and 11/16” SAE inverted flare fittings while gearboxes after 1980 will have 16mm and 18mm O-ring fittings. Again, the older SAE gearboxes are very hard to find, so the majority of the gearboxes we sell are metric. If you are installing into a pre-1980 vehicle that has inverted flare fittings, we can install a seat kit that will allow you to thread your existing hoses. Yes, the SAE thread pitch will thread into the metric threads!
Along with the change of fitting style in 1980, the input shaft also changed from 13/16-36 (pre-1980) to 3/4-30 after 1980. You can simply change the rag joint to accommodate a smaller input shaft. When counting the splines, it is important to know that the 30 and 36 counts include any missing splines that are removed where a flat on the shaft is.
SAGINAW 708 GEARBOXES
This gearbox was found in GM trucks and SUV’s up to 1986. It is easy to identify because it mounts on the outside of the frame and the mounting tabs are on the opposite side of the gearbox. Notice how the mounting holes are on the top side of the gearbox.
The one variable with the 708 gearbox is that it came with two different sector shafts. A threaded shaft (found in 2WD vehicles) and a notched shaft (found in 4WD vehicles).
Gearboxes before1980 will have 5/8" and 11/16” SAE inverted flare fittings while gearboxes after 1980 will have 16mm and 18mm O-ring fittings. Again, the older SAE gearboxes are very hard to find, so the majority of the gearboxes we sell are metric. If you are installing into a pre-1980 vehicle that has inverted flare fittings, we can install a seat kit that will allow you to thread your existing hoses. Yes, the SAE thread pitch will thread into the metric threads!
This gearbox was found in GM trucks and SUV’s up to 1986. It is easy to identify because it mounts on the outside of the frame and the mounting tabs are on the opposite side of the gearbox. Notice how the mounting holes are on the top side of the gearbox.
The one variable with the 708 gearbox is that it came with two different sector shafts. A threaded shaft (found in 2WD vehicles) and a notched shaft (found in 4WD vehicles).
Gearboxes before1980 will have 5/8" and 11/16” SAE inverted flare fittings while gearboxes after 1980 will have 16mm and 18mm O-ring fittings. Again, the older SAE gearboxes are very hard to find, so the majority of the gearboxes we sell are metric. If you are installing into a pre-1980 vehicle that has inverted flare fittings, we can install a seat kit that will allow you to thread your existing hoses. Yes, the SAE thread pitch will thread into the metric threads!
SAGINAW GMT GEARBOXES
This gearbox is found in GM trucks and SUV’s from 1987 on. It uses a 3 bolt “triangle” pattern. This box has many variations!
Piston Bore Size
There is a casting number on the housing of the gearbox (either 83 or 84). Casting number 83 is a “small bore” GMT400. Casting number 84 is a “big bore” GMT800. Most of the time: 1500 2x4, 1500 4x4 and 2500 2x4 use the small bore, and 2500 4x4, 3500 2x4, 3500 4x4 use the big bore, but there are some exceptions.
Blind Spline
Most vehicles use a sector shaft with 3 Blind Splines, but some (usually Diesels) have 4 Blind Splines. You will need to know which you have.
End Cap Number
Some models of vehicles have different internal stops to limit steering travel. There is a number on the end cap that will let us know what stops you need.
Input Shaft
It is also a good idea to verify your input shaft type. Vehicles from 1987-2000 should have a 3/4-30 splined input shaft and 2001 to present use a DD input shaft. Some models around the 2001 switch over may not follow these guidelines.
If you have all this information you can go through the pick boxes on our website and order the gearbox you need.
This gearbox is found in GM trucks and SUV’s from 1987 on. It uses a 3 bolt “triangle” pattern. This box has many variations!
Piston Bore Size
There is a casting number on the housing of the gearbox (either 83 or 84). Casting number 83 is a “small bore” GMT400. Casting number 84 is a “big bore” GMT800. Most of the time: 1500 2x4, 1500 4x4 and 2500 2x4 use the small bore, and 2500 4x4, 3500 2x4, 3500 4x4 use the big bore, but there are some exceptions.
Blind Spline
Most vehicles use a sector shaft with 3 Blind Splines, but some (usually Diesels) have 4 Blind Splines. You will need to know which you have.
End Cap Number
Some models of vehicles have different internal stops to limit steering travel. There is a number on the end cap that will let us know what stops you need.
Input Shaft
It is also a good idea to verify your input shaft type. Vehicles from 1987-2000 should have a 3/4-30 splined input shaft and 2001 to present use a DD input shaft. Some models around the 2001 switch over may not follow these guidelines.
If you have all this information you can go through the pick boxes on our website and order the gearbox you need.
I am still looking for identification on some Delphi gear boxes due to the fact that the old box I have that I am considering to rebuild for my truck has a Delphi casting number on it which I have not been able to id yet, might be a unicorn lol
