The Toyota Land Cruiser Gearbox
Navigating the world of Toyota Land Cruiser gearboxes can be a confusing task with the amount of variations available. This guide is designed to demystify the options available, focusing on the H-series land cruiser gearboxes, and provide practical advice for those considering upgrades or replacements including more insight to the H152 gearbox conversion.
The Basics of H-Series Gearboxes
The H150, H151, and H152 land cruiser gearboxes are known for their durability and are often considered interchangeable in terms of strength. Many opt for the H152 gearbox for its lower RPM in 5th gear on the highway, or as a replacement for a damaged gearbox, seeking the latest Toyota box with improved gear ratios.
This change over generally drops highway RPM down to approx. 2000rpm, tyre size depending. However, the H152 requires a modification to the input shaft when installed in vehicles other than those equipped with the 1VD V8 engine.
Variants for 80 Series Toyota Land Cruiser Gearbox (Manual Transmission)
All 80 Series models with manual transmissions, regardless of being a GXL or a base model (DX), come equipped with either a H150 or H151 gearbox, both featuring a center shifter design. Upgrading to an H152 in these vehicles requires changing the input shaft to either a 14 spline (for 1HD pressure plates) or a 21 spline (for 1HZ pressure plates) H151 input shaft to ensure compatibility.
Otherwise, all your gearbox accessories (bell housing, transfer case, shifters, shifter position, etc) will bolt straight onto this and go straight into the 80 Series Land Cruiser. Generally someone doing this swap over has a damaged transmission they’re replacing, so all the parts are accessible and compatible.
The 105 Series Toyota Land Cruiser Dilemma
For the base model DX 105 series, which is equipped with the smaller and weaker R151 gearbox (also with a center shifter), an upgrade to the H-series land cruiser gearbox is possible but requires a all the accessories of a H box to go along with it, such as shifters, transfer case, bell housing, clutch fork, etc.
The GXL 105 Series models, depending on the engine type (1FZ for FZJ105 or 1HZ for HZJ105), come with different gearbox and shifter configurations, requiring specific modifications for upgrading to the H152 or replacing an R151 with an H151. Essentially, if you want to swap over to a H152 you will need to swap the internals of the H152, into your H151 rear shifter gearbox case, while also swapping over the input shaft to your H151 shaft.
100 Series Toyota Land Cruiser and Beyond
The 100 Series manual models with the 1HD-FTE engine, are equipped with an H151 land cruiser gearbox with a rear shifter, and are highly sought after for conversions into GXL 105 Series vehicles being a direct swap in. Upgrading these to an H152 requires a swapping over the internals from the H152 and converting them into the H151 gearbox casing that you already have, as well as changing the input shaft from the V8 to the 1HD version of the H151 input shaft.
HDJ79 and VDJ79Toyota Land Cruiser Models
The HDJ79 and early VDJ79 models are fitted with the H151 gearbox featuring a center shifter, suitable for various conversions except into GXL 105 series. For the late model VDJ79, which comes with an H152 land cruiser gearbox, conversions for 1H engines involve swapping both the input shaft and bellhousing to accommodate the different engine type, typically using brand new parts to complete the process.
HZJ79 Toyota Land Cruiser Models
The HZJ79 comes factory fitted with the R151 transmission, again, the smaller weaker transmission. These have much the same story as the HZJ105 DX, where a center shifter H151 transmission will bolt straight in (or converted H152), but of course you will have to obtain all the accessories off a damaged H151 or source brand new parts as the R151 transfer case, bell housing, etc. will not swap over onto the new H box.
Conclusion
Choosing the right gearbox for a Toyota vehicle involves understanding the nuances between different models and configurations. Whether you’re aiming for better highway performance, replacing a damaged unit, or undertaking a conversion project, knowledge of the specific requirements and compatibility issues is crucial. By considering the gearbox strength, desired gear ratios, and necessary modifications, owners can make informed decisions that best suit their vehicle’s needs and their driving preferences.
