Swapping 6sp for 5sp

[Bob Stephens]

I was asked by a friend if a destroyed 5sp could be replaced with a 6sp. I don't know whether truck is 12v or 24v or even what year it is. What are the things to worry about?

 

[South Bend Clutch]

There is not a problem with doing this in any year.



Two places to call would be Standerd Trans. of Texas or Blumenthals of Oklahoma.



If you need their numbers call me Friday at work and I will give them to you. 1-800-988-4345



Peter

 

[KWIKKURT]

Bob, I would watch out for Peter (SB) I heard he wants $4600 just for his "Mug Shot" LOL



One Difference I know of would be that there is Two different Sixspeeds. The difference is the Input shaft size. With the Smaller input shaft (Pre 2001?) You have the older style Flywheel and have a larger choice of clutch combinations. With the Newer Larger input shaft 1 3/8? you have to change to a larger flywheel and there are only a couple of High HP clutch choices. There are several different suppliers of clutches but the only ones I would use are SouthBend Clutch (- the Mug Shot!) or Joe Donnely can also hook you up with HD Clutches. And you also have to space the starter with the Later transmission.



I am not 100% on all of my info so I may be corrected on a point or two. Hope this helps..... Kurt

 

[Cooker]

Isn't the physical size of the two trannies different. If so, you would also have to shorten the driveshaft.



Wasn't there a write up in a past issue about this swap?

 

[KWIKKURT]

Speaking of the last issue!! I didn't get mine!

 

[MikeR]

Kurt is right about the exisitence of two 6spds. They are the same trans in every aspect except for the input shaft. The early (99-00) has the same size input shaft as the 5spd trans, and the later style has a bigger diameter input. So if you get the early, you can keep your original flywheel and use a 5spd clutch. With the later style you have to get the HO flywheel and the starter spacer block and the HO style clutch.



-If you are mounting it in a 98 or older truck, you either have to get the 99 and newer transmission crossmember or simply redrill the mounting holes in your original because the transmission mount sits about 6" further back.

-You have to shorten the rear drive shaft and lengthen the front driveshaft.

-You have to get a longer transfercase shift rod.

-If it's going in a 97 or older truck you'll have to figure out how to drive the speedometer gear, becasue the 6spd doesn't have a place for speedometer gears to go in. the 98 and up trucks read the electronic sensor off the rear axle.



Or you can rebuild the 5spd with the fully splined mainshaft from Standard Transmission and have a better 'bullet proof' trans and be done.



-Mike

 

[pcorssmit]

The speedo hookup shouldn't be a problem in '97 and older 4x4s, only 2wds. The speed senser in the 4x4s is driven off the t-case.



Pete

 

[KWIKKURT]

Great Info!

This is what the TDR site is Really Great For. Look at how several different people can put together the information needed and Fast!!!!

 

[South Bend Clutch]

Guys,



We have had a few done in our area. I have gotten them for the customer from Blumenthals. Just recently you can order the trans. with either size input shaft if you get it from them. The only thing that came extra in the kit was a spacer plate for the trans. mount and a the reverse light wire harness. They tell you that you need a new shifter rod and sticker for the shifting pattern but all you need is the sticker. If you pick up a 6sp trans from the salvage or something you DO NOT HAVE TO CHANGE THE FLYWHEEL AND GET A STARTER SPACER to accommodate the 1 3/8' input shaft. I make our CON O clutch with a broached hub to take care of that problem!!! That will save you about $500. 00





Peter

 

[C1B1DIESEL]

SBC

I have been waiting for someone to just modify or build a clutch disk for a 5spd to 6 spd swap, with out having to change flywheel ect. or get the small input shaft.