Transmission/T-case Swap

Prior to 1971, Jeep used a GM BOP (Buick-Olds-Pontiac) bell housing with the 225. This was combined with a long input shaft and adapter to mate to the T-86 or T-14. Typically Jeep would stock the GM parts used in their cars under the GM part number, so it's essentially a GM bell. Same part.

 

Thats great news - one of the few times a Man hopes to have the shortest of something.

 

The jeep version of the BOP bell has a left hand starter bulge deleted and the part number cast in that section. I have sold a few BOP bells with the starter bulge on both sides and it really doesn't effect the use on a jeep.But if your going 100% correct you will pay more for the jeep version usually.

 

If you have the stock 1971 bellhousing, it won't work. The 66-70 V6's used a standard GM bellhousing with an adapter plate as mentioned above but in 71 they went to a one piece unit with no adapter.

 

one other note . the BOP bell housing double hump . doesn't play well with the frame mounted master cylinder

 

The ford t18 can be mated to the GM BOP bell housing without an adapter by some re-drilling and machine work etc. it will be the shortest combo. The 77-79 jeep t18 requires a 1 inch adapter plate to take up the extra input shaft length if you don't want to change out the shaft.

 

Sorry what won't work?

 

Yeah the trans should mate right up with some minor modifications to the T18.

 

The T18 won't work with the 1971 bellhousing

 

Thanks for telling me. Would have been a bear to get under there and wrestle a T18 for 3 hours only to wonder why it won't fit

Any idea if my current bell can be modified to work with the T18 or do I need a 70 and older bell? What would be the shortest years and models for the bells if I have to go hunting?

 

You need the 66-70 version

 

Is there an adapter that is a separate piece of the 66-70 bell that I should be getting with the bellhousing?

 

I see advance adapters has a bell I could use. As long as the stock bell and the T18 input length work I don't mind the work thats required to the T18 to make it mate. From what I see on the Novak site the stock non-71 bell and the Ford T18 will work.

 

Waaaaait a minute... I see what you did there!

 

Wont almost any buick, pontiac, olds 4 speed bell housing work with the short shaft t-18?
Ebay is plentiful 1968-72 BUICK GRAN SPORT GS OEM BELL HOUSING 9773320 | eBay

 

From what I understand the V8 is different - I could be incorrect.

 

I've been contemplating a 4 speed swap for the future as well, but I haven't been able to decide between the sm420, sm465, or the t18. Does anyone have the lengths of these different transmissions mated to a dana18? My first thought was the sm420 because I think it will bolt right up to the buick bellhousing, but then I saw the sm465 adapter was only 1 inch long. Now I'm wondering if a frankenstein t18 would be the best option

 

I believe Novak gives you that information on their site. Novak Conversions Home

The two GM Muncie transmissions (SM420, SM465) will bolt up to a GM bell without modification (mostly). The Ford transmissions (T-18. T-19, NP435) will bolt up to a GM bell with minor machining. Novak covers all of this on their site - just keep following the embedded links on their site and you will cover the issue completely.