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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: 1quik86 on June 11, 2004, 02:23:00 am

Title: Manuel to Auto
Post by: 1quik86 on June 11, 2004, 02:23:00 am

I wold like to convert from a 4speed manuel to a 350 auto. I would like to use my same T-case. What do I need to do? Will I have to change to a diffent tail shaft on the transmission etc?

Any help would be appreciated.

Title: Re: Manuel to Auto
Post by: 73K20 on June 11, 2004, 01:29:00 pm

You will need to clarify a bit more on what year your truck is and what t-case you currently have in order for me to tell you whether or not you can reuse the same t-case.  I am about 100% sure that you will not be able to use the case with no modifications.  I know that the input shaft for these two t- case are different due to the different output shafts used, 10 spline for the SM465 (in some cases 32 spline) and 27 spline for the TH350.  

I know that in a NP205 (which I am the most familar with) the two different input shafts use the same bearing in the t-case so it is a simple matter of swapping inputs to make one t-case work with both trannys.  I dont know if this applies to other t-cases or not though.

Also if you use the same model t-case you will not need new driveshafts, because the driveline lengths will stay the same.

1973 K20 - 350/465/205

Title: Year and Transfer Case?
Post by: 77 K30 Crew Cab Dually on June 18, 2004, 09:10:00 pm

Like what was previously mentioned; We will need to know what year model and which model transfer case.


Respectfully,
Dave

Title: re
Post by: 1quik86 on June 21, 2004, 07:46:00 pm

The truck is a 77 half ton. I always get the case numbers mixed up. It is a gear drive unit. I'll try to look at the tag and make sure of the number.

Thanks for the replies.

Title: Transmission Main Shaft
Post by: 77 K30 Crew Cab Dually on June 28, 2004, 09:28:00 pm

That is a problem I forsee you dealing with. It's a different spline count on your transmission output shaft.


Dave