[lamothe1]

I have a 1989 Chevy ½ ton truck with a 700R4 transmission. My overdrive stopped working, it acts like it’s in neutral if I select overdrive position on the gear selector. The other three gears work normal if I select the regular Drive position, not OD. Prior to the OD not working, the transmission made a shuddering type noise. I parked the truck right after the OD stopped working and would like to see if anyone knows of a simple fix? The local transmission shop has told me I need a total rebuild (at $1200). Also, I have `89 Camaro 700R4 tranny with a different tail shaft with cable speedometer that I would like to use if possible, does anyone know if it will work in the truck, which has the electric speedometer?

[tnsmith10]

Originally Posted by lamothe1

I have a 1989 Chevy ½ ton truck with a 700R4 transmission. My overdrive stopped working, it acts like it’s in neutral if I select overdrive position on the gear selector. The other three gears work normal if I select the regular Drive position, not OD. Prior to the OD not working, the transmission made a shuddering type noise. I parked the truck right after the OD stopped working and would like to see if anyone knows of a simple fix? The local transmission shop has told me I need a total rebuild (at $1200). Also, I have `89 Camaro 700R4 tranny with a different tail shaft with cable speedometer that I would like to use if possible, does anyone know if it will work in the truck, which has the electric speedometer?

it can be but, its going to take some effort. first, like you said, the extension housings are different and the truck came with a v.s.s. and reluctor where the camaro has a regular cable driven speedo.
the reluctor will have to be removed to be put on the other trans, or the output shafts will have to be swapped which means the trans has to come apart down just past the input drum as there is a snap ring that holds the output shaft in there.
this does need to be done as the pcm uses a signal from the speed sensor for the converter clutch to come on.
after that, the pans would have to be dropped and verify that theyre wired the same inside or that would have to be swapped as well.
so, yea, it can be done, but its gonna take some work to do it right.
i do have a curiosity question for you though, you say its lost overdrive but, with the way these transmissions are, if you loose o.d., then usually 3rd is gone as well. are you sure that its not the converter clutch that is no longer working?
how many miles on the truck? has the trans ever been built before? any recent service work done to it recently? whats the level and condition of the fluid?

[123pugsy]

You can use the Camaro tranny.
You will need to pull the reluctor gear from your truck tranny and install it on the Camaro tranny.
The speed sensor should fit the Camaro extension housing.

[123pugsy]

Originally Posted by tnsmith10

it can be but, its going to take some effort. first, like you said, the extension housings are different and the truck came with a v.s.s. and reluctor where the camaro has a regular cable driven speedo.
the reluctor will have to be removed to be put on the other trans, or the output shafts will have to be swapped which means the trans has to come apart down just past the input drum as there is a snap ring that holds the output shaft in there.
this does need to be done as the pcm uses a signal from the speed sensor for the converter clutch to come on.
after that, the pans would have to be dropped and verify that theyre wired the same inside or that would have to be swapped as well.
so, yea, it can be done, but its gonna take some work to do it right.
i do have a curiosity question for you though, you say its lost overdrive but, with the way these transmissions are, if you loose o.d., then usually 3rd is gone as well. are you sure that its not the converter clutch that is no longer working?
how many miles on the truck? has the trans ever been built before? any recent service work done to it recently? whats the level and condition of the fluid?

Sounds like it will only manually upshift.
Would this be the low roller clutch?

[tnsmith10]

your right bud, i misread. good catch!
if it wont take off in o.d. and have no o.d. as well then that would be the input sprag.

[Crosley]

forward clutch is smoked I bet since the comment of shuttering was posted.. in the "D" position the over run clutch comes on and the vehicle moves

[lamothe1]

Originally Posted by tnsmith10

i do have a curiosity question for you though, you say its lost overdrive but, with the way these transmissions are, if you loose o.d., then usually 3rd is gone as well. are you sure that its not the converter clutch that is no longer working?
how many miles on the truck? has the trans ever been built before? any recent service work done to it recently? whats the level and condition of the fluid?

I was told by the previous owner that the trani had about 5000 miles on it. The trans works fine in "regular drive" position, but not in overdrive position.

[lamothe1]

Originally Posted by 123pugsy

Sounds like it will only manually upshift.
Would this be the low roller clutch?

no, i don't need to manually up shift it. in drive it goes thur 1st, 2nd & 3rd normally.