Le Bad Tranny

If you are looking to buy a used Wrangler or Cherokee and you want a five-speed, you’d better take a look at the transmission to make sure you don’t get stuck with a Peugeot. The Peugeot, if in good running order, is just barely OK for stock vehicles. If you want to run bigger tires, add power mods, or go ’wheeling, avoid this transmission unless you plan on replacing it with something more suitable.

The best identifying feature of the Peugeot is the clamshell-style transmission housing. Look for the seam running lengthwise down the transmission where the two halves are bolted together (arrow). Not only does this make the transmission easy to identify, it also weakens the overall unit.

Here, you can see the hydraulic throwout bearing and the wacky Peugeot bolt pattern on the stock bellhousing.

Here you can see a complete BA 10/5 next to a bit of another one. The clamshell design may seem easier to work on, but apparently it is not. And the parts are—how you say?—trés expensive.

The French are responsible for many memorable American icons such as the Statue of Liberty, the scantily clad French maid, and the always-amusing Pepe Le Pew. Unfortunately, they are also responsible for a few badly engineered pieces of machinery that can be found in America today. For example, Le Car, which seemed to be made of le super glue and le compressed rust, not to mention the vex of many a Jeep owner, the Peugeot 5 speed, or BA 10/5.

Although the Peugeot may be hiding behind any of the powerplants in Cherokees and Wranglers, the Jeeps most commonly infected are ’87-’89 YJs with the 4.2L straight-six, and some early 4.0L Cherokees. Fifth gear seems to be a weak point along with the clamshell-style housing design. If one gear starts to go south expect the rest to soon follow suit.

The Peugeot transmission offers a marginal First gear of 3.39 and does not have a good reputation when it comes to longevity. Add bigger tires and difficult terrain and you have a dead BA 10/5, and a transmission in need of parts that are both hard to come across and generally very expensive. Even though adapters are available for the Peugeot, don’t even think about an engine swap. However, there is a wide array of swapping options available to rid you of the French tranny, some of which are cheaper than rebuilding your BA 10/5 with new yet prone-to-break components.

If you own a Cherokee with the Peugeot and the 2.8L you may be thinking of losing that V-6 anyway. Let’s face it: That was not GM’s best work. And with the curse of the Peugeot gearbox, now may be the time to get rid of both. Keep in mind that when mounting any of these transmissions to a factory fuel injected motor like the 4.0L, you need to have plans for the crank sensor, and how you are going to replace your hydraulic clutch mechanism if you’ve decided to stick with a manual transmission. All of Advance Adapters’ bellhousings for both the Ford-style manual transmissions and the GM manuals have a crank sensor location. If you are using a GM automatic transmission, or a bellhousing from an older Jeep with your 4.0L, you need to get a kit from Hesco to relocate the crank sensor to the harmonic balancer, or (we hate to put it bluntly) your engine won’t run. We have heard of people who had their bellhousings machined to accept the crank sensor, but this is not as easy as it seems and must be done properly in order to function.

You also need to remember that the NP231 that was attached to a Peugeot is generally equipped with the slightly weaker 21-spline input shaft. Some of the transmissions discussed in this article will require you to replace this shaft with the slightly stronger 23-spline input shaft, while others have parts available to make them work with either input shaft.

Here’s some sweet swaps and other tips we found. Hopefully, you’ll be able to wash that overripe escargot taste out of your mouth for good, and keep shifting down the trail with improved performance and confidence in your equipment.