Pontiac GTO 1967 400CID 4sp manual OVERDRIVE or Tremec 6 speed Magnum

Dedek963

The European guy
89
1
8
Prague
Hi guys,
some time ago we discussed the way how to mount the Tremec gearbox.
I have to say, I wasn't right when I thought, that I can resolve the difference in the size of the gearboxes by using higher silent blocks. This would have been a nice workaround but I would have to modify the steering shaft.
So I went the standard way and did the floor modification.
You can see it on the picures.
On the other hand I did not use the SST crossmember and did not cut the frame to fit it into it. Instead of this I used the "original" cossmember from (probably) Buick or Olds. (some posts above).

It fits perfectly. IMG-20200406-WA0002.jpg
Only the opening had to be modified.

20200324_174827.jpg IMG-20200326-WA0008.jpg
 

Dedek963

The European guy
89
1
8
Prague
I am just being curious because of this:
IMG-20200529-WA0007.jpg IMG-20200529-WA0008.jpg IMG-20200529-WA0009.jpg
What supplier of differential parts would you recommend me (just for the case)
The ring gear seems to be a bit used up and the pinion gear too.
The diff is working perfectly, no vibrations, perfectly silent.
Is this look usual or is it a mark of being used up to some limit?

I would like to keep the YH spec 3.55 (preferable). If not possible I would go for 3.90.
 

melsg5

Staff member
SUSTAINING MEMBER
21,524
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63
Send an email to gtrvette1999@gmail.com he is a re-builder of Corvette and other differentials and he literally blueprints them, doesn't just slap in new bearings, gears, etc. Send him these pictures. He may know me from the Corvette forum as MelWff.
I would be hesitant to mess with it since getting good quality gears can be difficult and you are having no issues other than what the pictures show.
Let me know his response.
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Dedek963

The European guy
89
1
8
Prague
Gary wrote:
___
Well my expertise is with 1963-82 Corvettes, but that looks like the diff was sitting for some time. I see that on gears found in steering boxes that sat a long time and the oil became a slug with moisture mixing in. I would not use them. You can contact Drive Train Specialties in Michigan they should have the parts you need.

Tell Mel I said Hi
___
So here we are :-/
 

Dedek963

The European guy
89
1
8
Prague
I figured he would have seen something like that and would know best.
I was afraid that the cavitation is caused by corrosion.
Gary confirmed my feeling.
I already wrote to those guys from Michigan.
Lets see if they have the parts.
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Dedek963

The European guy
89
1
8
Prague
They have the parts needed. So no problem.
Their suggestion is: Use it, it can last forever. If it starts to fail come back to us.
 
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melsg5

Staff member
SUSTAINING MEMBER
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63
Makes sense, you have had no problems and replacement may start other issues if the ring and pinion aren't set up correctly.
 

melsg5

Staff member
SUSTAINING MEMBER
21,524
208
63
So this is just stationary, the car is not on the road yet?
I see from your other posts it is on the road.
That is a very popular transmission for many applications.
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