69 Transmission

MICAH1 · 05-01-2007

Having my clutch replaced tomorrow morning, and will have the four speed manual transmission checked during the process. If I run into a suprise with the transmission I have a spare 1969 back-up. Question, can the 1969 transmissions be swapped to a 1973 GT?? Did not see anything in the search engine on this topic.

yellaopelgt · 05-01-2007

I do believe that the only difference's might be the speedo cable hook-ups.I do know the early vs. later cables are of different lengths and the actual outputs on the tranny are different. I am not sure about the back-up light switch either, someone else may be able to chime in on that issue......
Joe

Anonymous D · 05-01-2007

You would need to check, whether you need to extend the wires to the backup light switch, as well as whether your speedometer cable will reach the end of the "L-shaped" gear "extension" piece.

Check the condition of the seals in the 69 before installing it. Replacement seals are sold for the speedometer gear (2), shifter shaft (2) and rear output (1). You can swap over an existing front cup seal, or replace it with a new one.

Always replace the gasket to the bellhousing when reinstalling a transmission, and use gasket sealer (to avoid leaking gear oil from the trans). If the used trans has worn gears, filling with "straight" 140W gear oil (not multi-viscosity) will quiet them.

MICAH1 · 05-01-2007

Just talked to Gil at OGTS who said the problem with the swap would be the speedometer would read way off. I'll keep my fingers crossed that the trans is ok. Guess I will bring the part up to Carlise, to sell or give away...

Anonymous D · 05-01-2007

Simply replacing the dash speedo with a W=897 gradient speedo, would keep the MPH readout gearing accurate.

nobody · 05-01-2007

The 69 uses the same speedo cable but on the opposite side and uses a 90 degree drive for it. The 69 and 70 had an external reverse switch where later years were internal. All the speedo driven gears at the tranny side are interchangable although some are pinned in place and some have a bolt in piece. Swap the driven gear from old to new and you will be fine. The older wires for reverse are a bit longer but wire up the same. HTH

soybean · 05-02-2007

Originally Posted by Anonymous D

Simply replacing the dash speedo with a W=897 gradient speedo, would keep the MPH readout gearing accurate.

Thomas, if you go with that 69 swap, I have 3 dash speedos with a W=897 on the face should you need them. The 90 degree drive, I don't have as I was looking for one for Karl earlier this year. Jarrell

05-01-2007	#1 (permalink)
MICAH1 101st Airborne Vet V.N. Join Date: Jun 2003 Location: Fort Washington, Maryland Posts: 643 Real Name: Thomas Johnson	Unanswered: 69 Transmission Having my clutch replaced tomorrow morning, and will have the four speed manual transmission checked during the process. If I run into a suprise with the transmission I have a spare 1969 back-up. Question, can the 1969 transmissions be swapped to a 1973 GT?? Did not see anything in the search engine on this topic. __________________ Thomas

05-01-2007	#3 (permalink)
Anonymous D Opeler Join Date: Aug 2004 Location: Planet Earth Posts: 502 Provided Answers: 3	69 vs. 73 Manual Transmission You would need to check, whether you need to extend the wires to the backup light switch, as well as whether your speedometer cable will reach the end of the "L-shaped" gear "extension" piece. Check the condition of the seals in the 69 before installing it. Replacement seals are sold for the speedometer gear (2), shifter shaft (2) and rear output (1). You can swap over an existing front cup seal, or replace it with a new one. Always replace the gasket to the bellhousing when reinstalling a transmission, and use gasket sealer (to avoid leaking gear oil from the trans). If the used trans has worn gears, filling with "straight" 140W gear oil (not multi-viscosity) will quiet them. Last edited by Anonymous D; 05-01-2007 at 01:41 PM.

05-01-2007	#4 (permalink)
MICAH1 101st Airborne Vet V.N. Join Date: Jun 2003 Location: Fort Washington, Maryland Posts: 643 Real Name: Thomas Johnson	Just talked to Gil at OGTS who said the problem with the swap would be the speedometer would read way off. I'll keep my fingers crossed that the trans is ok. Guess I will bring the part up to Carlise, to sell or give away... __________________ Thomas

05-01-2007	#5 (permalink)
Anonymous D Opeler Join Date: Aug 2004 Location: Planet Earth Posts: 502 Provided Answers: 3	Speedo can be changed Simply replacing the dash speedo with a W=897 gradient speedo, would keep the MPH readout gearing accurate.

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05-01-2007	#2 (permalink)
yellaopelgt No....its not a Buick.... Join Date: Feb 2005 Location: IL. Posts: 1,042 Provided Answers: 1	I do believe that the only difference's might be the speedo cable hook-ups.I do know the early vs. later cables are of different lengths and the actual outputs on the tranny are different. I am not sure about the back-up light switch either, someone else may be able to chime in on that issue...... Joe

05-01-2007	#6 (permalink)
nobody No Access Join Date: Nov 2003 Location: in transit Posts: 3,873 Provided Answers: 1	The 69 uses the same speedo cable but on the opposite side and uses a 90 degree drive for it. The 69 and 70 had an external reverse switch where later years were internal. All the speedo driven gears at the tranny side are interchangable although some are pinned in place and some have a bolt in piece. Swap the driven gear from old to new and you will be fine. The older wires for reverse are a bit longer but wire up the same. HTH

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