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Trying to put the finishing touches on a 4BT for 6.5 swap in a 97 H1 Hummer. Does anyone know of a flywheel cover that will work with a 4BT/4L80E combination, or do I have to fab one myself. Also, I have a crank pulley off of a 6BT (out of a dodge) with 2 notches for the crank position sensor, and a dodge cps. I am trying to make the stock tachometer work, but tried to wire up the existing harness that went to the 6.5 cps to the dodge cps (both had 3 wires), with no luck making it work. Does anyone know how I can make it work, or do I have to install a different tachometer? Thanks for your help Ron
 

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Do you know what kind of sensor was used for the stock tach? If so, we can help you duplicate that signal. It is "looking" for a certain thing and it is not likely the same as a dodge.

The flywheel cover is a no go from what I have found. You could use a 4L80E cover and cut the front out, but it will not bolt to the engine plate. I have the same issue and I am planning to fab one up that will bolt the the engine plate and transmission so it offers some strength to the trans case as well as covering every thing up. It looks straight forward. You can cut a ring from plate steel and bolt to the engine plate. Then cut straps and bolt to the tranny. Last is to properly curve some 1/8" plate to make the actual cover. I think it can be done with two continuous pieces welded together. I plan on making one to cover the converter at 90 degrees to the engine plate and then one at 45 to that piece to close the back. Cardboard templates will be your best friend on fitting those.
 

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I've seen the correct cast aluminum GM auto/4BT TC cover, but most don't seam to have one. Probably like trying to find a needle in a hay stack.
 

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The Gm tach are ran buy the alternator .

Scott
Autometer also makes an aftermarket tach that has a sensor you clamp around the alternator. Not an ideal setup, but it works well.

MIke

BTW, I didn't want to be the first to ask, but do you have any pics of your swap? bounce
 

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I've seen the correct cast aluminum GM auto/4BT TC cover, but most don't seam to have one. Probably like trying to find a needle in a hay stack.
They are part of the pan. I had one on my TH400, but the bolt patter on the bell housing is different on the 4l80E. I was going to use a TH400HD pan with the front cut out, but found the difference after spending 20 minutes sawing the front out of a perfectly good HD cover.
 

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I used the GM tach in my Suburban

I also used the stock GM a/c pump. I can send pics if I can find them.
 

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Thanks for your responses. I don't believe the tach on this was ran by the alternator, as there was only one wire on the regulator plug, besides the main output wire. I think (not sure though) that the alternator did run the tach on the hummers with the 6.2's and the 6.5's before they added the computerized pumps. I'm not sure what kind of cp sensor was used in the 6.5 I removed. I assume it was the same one used on all the 6.5's, but not sure. I'm not even 100% sure that the tach is ran off of the cps alone. Someone told me it was ran off of the optic eye in the pump, along with the cps. I was just hoping to be able to run the existing tach, instead of adding a external mounted one. Might not be able to do so.
I will try to get some pictures of the swap before I send it back to it's owner. Thanks, Ron
 

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Thanks for your responses. I don't believe the tach on this was ran by the alternator, as there was only one wire on the regulator plug, besides the main output wire. I think (not sure though) that the alternator did run the tach on the hummers with the 6.2's and the 6.5's before they added the computerized pumps. I'm not sure what kind of cp sensor was used in the 6.5 I removed. I assume it was the same one used on all the 6.5's, but not sure. I'm not even 100% sure that the tach is ran off of the cps alone. Someone told me it was ran off of the optic eye in the pump, along with the cps. I was just hoping to be able to run the existing tach, instead of adding a external mounted one. Might not be able to do so.
I will try to get some pictures of the swap before I send it back to it's owner. Thanks, Ron
The tach was run by the alt from 95 up gas and diesel trucks ,tahoe ,burbs .

Scott
 

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Autometer also makes an aftermarket tach that has a sensor you clamp around the alternator. Not an ideal setup, but it works well.

MIke

BTW, I didn't want to be the first to ask, but do you have any pics of your swap? bounce
Yes Autometer does make a tach and has a pick up that uses the alt windings ,and then you need a photo tach and tape to check the rpm and then adjust the tach.

Scott
 

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Yes Autometer does make a tach and has a pick up that uses the alt windings ,and then you need a photo tach and tape to check the rpm and then adjust the tach.

Scott
Can I adjust the tack in a 93' burb'?
 

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