Hi all,

I have a vibration in the drivetrain of HT Monaro, original 350 SBC with M21 4sp.
Bought and installed new gearbox mount 6 months ago from RareSpares when clutch was replaced.

The RareSpares mount was 55mm high and we discovered this was higher than standard and put driveline out of alignment.
We no longer have the original gearbox mount but want to know the height of the original mount.

Is anyone able to tell me the height of the original mount for HK/T/G with SBC and 4sp Saginaw?

Thanks in advance.
Steve

Edited by user Sunday, 8 April 2018 2:06:59 PM(UTC)  | Reason: Not specified

The parts book shows that you may have needed part 3870184, which doesn't show on the Rare Spares list. What part number did you purchase.?

I used part 7432236 for my car (HT 350 4spd but was a 253 4spd) and it seems to work well. I don’t have any issues with the shift rods or gearbox clearance or alignment. I understand they used the same part up till VL's. I actually have a shot of the old mount (rather squashed and stuffed and showing orange overspray) and the above part showing the height and it was pretty darn close. This may actually suggest the original mount was slightly taller but squashed over time. Unfortunately I don’t have the height for 7432236 or the original mount (as I can’t find it at present).
Page 178 of the parts book (see GM I do use it ;-) shows details for the heavy duty 4spd. Again, item number 1 is the rubber mount; 4.081 refers. Page 180 against 4.081 does state that the 7432236 is for the six cylinder engine combos. The chev engines (307, 350) use part 3870184 as TD noted.
The mount on page 178 looks like the one I used but… I did some googling and found that 3870184 was superseded by part 334528 (http://www.gmpartswiki.com/w/3870184). You can get something similar from summit. A reviewer noted this part is 1 5/8inches (41.275mm) and another noted it was shorter than the original but still worked for them.
BUT but…
More googling found that part 3913498 is also a replacement for 3870184. I found one on that auction site and again, it looks like 7432236 that I used. I have emailed the seller for the height so stay tuned. Here is a link to a pic : http://www.corvettepacif...nd-68-81-4-speed-63-81/ Part 3913498 is used on 1963-81 corvettes so might be correct for our application.
What is the part number from RS that you are querying?

quick update. Auction site replied (God bless them)and the height of 3913498 is 1 7/8inch or 47.625mm. Seems to be a good match for GM's 48mm.
Cheers
Jacko

Thanks everyone for the specs, measurements, photos etc.



Dad bought the part middle of last year at Rare Spares, unfortunately I wasn't with him/dont have receipt so I don't know what part #. I only know that he went in and asked for gearbox mount for HT 350 with 4sp Saginaw. So I'm not sure of the part # however it looks like this kit here:

https://www.rarespares.n...werglide-hd-hr-hk-ht-hg

The mount Dad received is 55mm, we have been told that is not the standard height but weren't sure of the original mount height.

It may be that the vibration is not caused by gearbox mount height - that was just Dad's theory.
The tyres were purchased new and put on the rims (& balanced) about 2yrs ago but we only recently started driving it (2 months ago). To be sure we had the wheels re-balanced but the vibration remains at 100km/h or above.

Now that tyres are known to be balanced the only thing left I can think of is the tailshaft or maybe something in the diff (bearing, warped axle)?

Thanks again,
Steve