Sometimes I feel like people just get their answers then go watch pro wrestling for a month while their car gathers dust.
Overdrive Swap
Thread Starter
Instructor
Joined: Apr 2007
Posts: 127
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Overdrive Swap
I have a noisey transmission in 1st, 2nd and 3rd gear with a good overdrive and what I think is a good gearbox with an overdrive unit that has a crack on the support beam bolt hole. Question : If I swap the OD units will anything fall out of place when I remove the units. I think that I need GM PN J-34681 to keep things from going sprong. I imagine this is a bolt. Anyone know what size?
Thanks in advance.
Thanks in advance.
Last edited by edoad; Apr 9, 2007 at 07:45 PM. Reason: Add Info
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
You don't need any special GM tools.
First, remove all the bolts that connect the two units. There's one very tricky one on the bottom above the pan flange. To get this off, I had to remove the brass cooler line fitting, and then could fit a box end 17mm combo wrench in there. You'll probably need a 12-pt, it's very tight, but was just enough to turn the bolt a tiny bit at a time.
When you have all those out, get a cinderblock or something, set the trans upright on that, input shaft pointing down. Then you can lift the overdrive out. The reverse rod is attached to the overdrive case, and it holds the reverse idler gear bearings and washers in place. If you tip the 4-speed after this, they will slide out of place, so if you have to move it, use a dowel or something to hold them in place.
Worst case, you'd have to remove the side cover to get them back in place before putting the overdrive back on.
I have an overdrive unit if you're interested.
First, remove all the bolts that connect the two units. There's one very tricky one on the bottom above the pan flange. To get this off, I had to remove the brass cooler line fitting, and then could fit a box end 17mm combo wrench in there. You'll probably need a 12-pt, it's very tight, but was just enough to turn the bolt a tiny bit at a time.
When you have all those out, get a cinderblock or something, set the trans upright on that, input shaft pointing down. Then you can lift the overdrive out. The reverse rod is attached to the overdrive case, and it holds the reverse idler gear bearings and washers in place. If you tip the 4-speed after this, they will slide out of place, so if you have to move it, use a dowel or something to hold them in place.
Worst case, you'd have to remove the side cover to get them back in place before putting the overdrive back on.
I have an overdrive unit if you're interested.
Thread Starter
Instructor
Joined: Apr 2007
Posts: 127
Likes: 0
Thanksfor your input.
I have a good over drive on a bad transmission and vice versa so I only need to swap O D units. Thanks for the offer though. I think the one in the car was run out of oil. It growls and has a gear rattle at 60 or so MPH at times.
I was thinking of something like this, standing them upright and changing the units but was not sure it would work. I also read an overhaul post on the overdrive and it talks about clamping the clutches before removing the adapter. The photos though never show the OD being removed from the trans and I thought the adapter may be the diaphragm in the front of the OD. I did not know.
Regards,
I was thinking of something like this, standing them upright and changing the units but was not sure it would work. I also read an overhaul post on the overdrive and it talks about clamping the clutches before removing the adapter. The photos though never show the OD being removed from the trans and I thought the adapter may be the diaphragm in the front of the OD. I did not know.
Regards,
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
You don't have to mess with any overdrive clutches or anything. Just look down where the reverse idler rod will go into the 4speed, and make sure the washers and thin bearing are lined up, and the splines go in. Don't forget to seal the surface between them, as it contains gear oil.
I have not found a source for the gasket, if there is one. I had to make one out of gasket paper.
I have not found a source for the gasket, if there is one. I had to make one out of gasket paper.
Thread Starter
Instructor
Joined: Apr 2007
Posts: 127
Likes: 0
No Dust
No dust but I'm getting gooey. Put in clutc disk, pressureplate and throwout bearing today. Damn its dirty under there. Will put the transmission back in tomorrow then start on the rear end. Going to put in 3.54 gears. Looking for a reasonably priced speedometer corrector. Tried the Yellowbox but they don't know what setup will work.
Regards
Regards
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