The Novak Guide to the

Peugeot BA10/5 Transmission

jeep_peugeot_ba10_5The Peugeot BA10/5 transmission is a five-speed, overdriven, light-duty, passenger car transmission used by AMC Jeep from 1987 until mid-1989 in the YJ Wrangler, XJ Cherokee and MJ Commanche with the AMC 258 & 4.0L I6.

The 10/5 transmission had a poor record for durability and service, and consequently had the distinction of being the transmission with the shortest production run in Jeep history. It was gradually replaced by the AX15 during the 1988 model year.


The BA10/5 as found in Jeeps is 16-7/8" long. Its case is split longitudinally down the center. Its case and tailhousing are made of cast aluminum and its shift control is located in the rear portion of the transmission. The BA10/5 bellhousing mounting face has five mounting studs and two dowel pins for alignment.

In terms of identification numbers, it may have a "SIMI" and "3.283..." cast into the front and side of the case.

Part numbers for the BA10/5 may include: 53002035, 53002838, 53003234, 53005248, 53005251, 53005252, 53005451, 53005453, 53005454.


Gear ratios for the BA10/5 are: 3.39, 2.33, 1.44, 1.00, 0.79, for first through fifth gears, respectively.

The BA10/5 is a laterally loaded and assembled transmission. It has an 1-1/8", 10 spline input shaft. It will most likely feature 21 splines on its output shaft, though we have heard limited accounts of later units possibly having 23 splines.

The BA10/5 was only offered in Jeeps with the internal, integrated hydraulic slave cylinder throwout bearing, which were also notoriously problematic.

Transfer Case Adaptability

ba10_5_drivers_sideThis transmission natively mates to the Jeep New Process style transfer cases. It came married to the NP207 and NP231 transfer cases. It is generally not compatible with nor likely worth adapting to other transfer cases.

Engine Compatibility and Adaptability

The Jeep BA10/5 was found against the AMC 258 I6 in the YJ Jeep and behind the 4.0L in the XJ / MJ. It has a unique front bolt pattern that is not a match to any other Jeep bellhousing or transmission.

Because of the transmission's weak service record behind even stock Jeep powerplants, we do not offer any conversion to GM V6 or V8 power. This is essentially a small car transmission in a truck. The customer's efforts and funds are best spent converting to a stronger transmission during the engine upgrade. This is not a difficult thing at all and these details are discussed in the following articles:

Upgrade Options

In the throes of their financial decline in the mid-to-late eighties, AMC Jeep was in the unenviable position of purchasing transmissions on extremely tight budgets. The BA10/5 and its associated problems were a consequence of these realities.

While it is possible to rebuild a BA10/5, the general weakness of the hard parts and the tendency of the case to stretch (which results in gears not meshing as designed to) is often throwing good money after bad. It is possible and recommended to upgrade to a more durable transmission. Some suggestions include:

SM-420 transmission SM-465 transmission T-18 NP-435 transmission AX15
SM420 (*) SM465 (*) Ford T18 (**) Ford NP435 (**) AX15 (***)
* Adapting the AMC I6 to GM SM420 or SM465 Transmissions
** Adapting the AMC I6 to Ford transmissions
*** AX15's are highest recommended in most situations. Available new. No driveshaft length changes required.


  • The Novak archives and installation projects
  • Novak customers and their project input
  • Jeen at Stork's Jeep

We welcome any contributions or clarifications to this article. Contact us here.