stick to auto swap,'69 3/4 GMC

Hi.Does anyone here have personal experience with such a swap? I currently have a 2500 GMC P.U. with a 435 4sp.and the old knee is starting to complain about the clutch duty.So I want to put in an auto,either a T.H.
400 or a more modern unit (must be very heavy duty).-or even a 400 with a lock-up. Question 1) How much work is involved? " 2) Is there a trans.better than a 400,perhaps with lock-up converter or even 4 gears,that I could put in there? Currently has a 350 motor,3.73 rear,used to haul large loads. Thanks a lot !......Brian O.
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<g> Ah, the pains of being old... Looked into knee replacement? That may be a better solution if you have medical insurance.
I, myself, like automatics in trucks. They last, work well, and generally are easier to drive. (I too am old, and have had both many times over) Automatics don't fail any more frequently than manual transmissions. An automatic is not a sissy solution--many big rigs now are automatic, and all will be within the next ten or so years. Big rig drivers have also gotten tired of shifting and shifting and shifting, and... <g>
How hard? Find a similar truck with an automatic and it is easy, you can get the parts needed off it. OTherwise find an engine (with automatic) that is similar to your engine and get parts from it. You may have to work on the tail shaft (I am guessing it is not 4x4...) and rear crossmember.
Not a trivial swap, but probably doable.
On Tue, 25 Jan 2005 16:56:19 -0800, snipped-for-privacy@webtv.net (Brian Orion) wrote:

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X-No-archive:yes Thanks for the reply. I'm not that old,just high mileage on the knee and some pretty stiff clutches throughout the years.I still may try to lube all the linkage points and reduce the spring tension and also I noticed there are two positions for the clutch rod-to fork matchup.If I move it out I can get better leverage on the fork.Sure don't want to do a conversion to auto,but this is really getting painful! Brian O.
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I was serious on the suggestion on knee replacement. Age is not the factor, I've seen some rather young people who needed it.
On Wed, 26 Jan 2005 23:10:44 -0800, snipped-for-privacy@webtv.net (Brian Orion) wrote:

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Hi,     I have done engine and tranny swaps several times. All you need is the tranny, a balanced torque converter for your engine, and maybe some drive shaft work. You will also need a tranny cooler. The TH 400 is a very good tranny. I have rebuilt them (someone had done a sh##!?**t job of rebuilding them earlier.) They are of a good design. The only weak spot is the ported bolt that secures the valve body to the reaction assembly. When they break you lose all motion. I replace them, but I smooth the seat in the valve body with a smooth grinding stone. I then hold the reaction gear to one side and then I tighten the bolt down. This is required on all 350s and 400s. They use these trannys alot in racing. I don't know much about many of the new GM stuff, but I have had some very bad experiences with the newer trannys such as the TH200 and the TH 700. The 700 comes in the corvettes and trucks I think. You can get a shifter at any parts or performance place. The tranny may accept the drive shaft as is. Sometimes the tranny mounts, length, and output shaft are the same for sticks and autos. Try to find a parts supplier that sells wholesale (jobber). You can tell them you work for the government as a mechanic. They'll sell to you. There are also driveline specialists that can do any modification or good replacement and balancing of your drive shaft. Good luck. Jessie
Brian Orion wrote:

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Thanks Jessie.I found a shop that will do the swap for "about $1200-1600". Very reputable shop,some extra work on trans (shift kit,etc.).They will fab new cooler lines and mounts as needed. I'll tell the guy about that bolt you mentioned. Thanks again....Brian Orion
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